Primitive Archer
Main Discussion Area => Bows => Topic started by: Stick Bender on March 05, 2017, 08:48:55 am
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Hi Fellas I just got this bow all ready this week end to degrease and get the sinew on over the next week or so I was planing on reverse stringing in another 2 in of reflex for a total of about 4 1/2.in I was planing on using the Adam Korpowitz method of adding more reflex after jelling to put the sinew into compretion I know Adam spoke to not wrapping the sinew in his book but with all the interest in sinew lately I was wondering what methods others prefer ? This is only my third sinew bow & thought It might be a interesting topic for technics & tips ?
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You know my opinion Ritch.
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I usually do wrap a new sinew job with strips of old bed sheets to help smooth out the sinew and to be sure it stays secure to the limbs. After a few hours I remove the wrap and allow the sinew to dry and cure out.
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Did he give a reason not to wrap? I can't imagine it harming anything unless it slows its drying, or if you leave it on too long. But now i wonder
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My how to on here (somewhere) shows you a method for making your sinew practically glass smooth. It eliminates all of the pitfalls of a sinew job that people run into. Gelling too fast, too much glue, smoothness, worrying about how finely shredded the sinew is etc.
Adam is very likely using slow gelling fish bladder glue. Not very comparable to fast gelling hide glue or Gelatin.
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_0056_zps46691090.jpg)
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I've only sinew backed a half dozen bows and never wrapped any and I have not had any problems. I do tie the sinew down with some with extra sinew at the tips and at the center of the handle to keep it from lifting as it dries and that seems to do the trick.
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Virtually no downside to wrapping and many potential benefits when combined with re-heating. Seems like an easy choice to make.
Of course if you want a typical gnarly ridged bark like job that cracks and groans..... >:D
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The reason I use old bed sheets is because they are thin and they breathe plus I only keep the wrap on for a few hours.
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gfugal he does offer a lengthy exsplanation in his book to long for a thread but in a nut shell after the hide glue gels he adds additional reflex to the bow putting the sinew into compretion locking it to the core he exsplanes in detail is in his book I know some of those short 40 in. Bows are pull upwards of 130 lb and he claims that he never had a sinew failure but I don't know if wrapping would be compatible with that method he also said there was never any evidence of wrapping in the ancient Turk bows , but it was pretty common among Native American tribes
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One reason why maybe Adam might not condone wrapping especially if it's heated is on extreme stressed designs on horn bows it should'nt be starved any of glue.A 1 to 1 ratio of sinew to glue is his reccomendation.On regular self bows less stressed I don't think it's that critical.Measuring myself on self bow designs or longer working limbs in paticular I think my ratio many times is 1 to 1/2 sinew to glue.Mass weight wise.
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Ok then maybe I will try the wrap method I was just attracted to the locking to the core part !
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If any body finds a link to Patm sinew build along post it please I'm not finding it ?
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http://www.primitivearcher.com/smf/index.php/topic,43246.0.html
It was a sticky in the archives
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Putting the sinew into compression and "locking it to the core" is a bit of a stretch of an explanation. It's still a passive blob at that gelled stage. You're really just letting it sag into the concave of the reflexed back and preventing it from shrinking, pulling up and bridging the gap instead.
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The dynamics of what goes on putting sinew on before and after drying and later after shooting a bow I'm sure Adam has done more research on than anyone else on here.Although everyone is entitled to their opinion.
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The reason I use old bed sheets is because they are thin and they breathe plus I only keep the wrap on for a few hours.
-my wife would kill me if I took her bed sheets... I wonder what would be the cheapest substitute as far as clothe?
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My solution now is to combine the cloth and inner tube process together. I buy rolls of a support bandage such as vetwrap or similar product in black color.
A few dollars a roll and re-useable with a bit of care.
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you can still pull it into reflex if it is wrapped or not,,
most guys to tighten or raise the brace as the sinew cures,,
really,, I think if the bow is holding 4 inches to 6 inches of reflex when you put the sinew on you are good,,
wrapping it for short time at least is gonna smooth it down a bunch,,
but I dont think its gonna hurt the sinew to not wrap it,, I have tried it both ways,,
and preferr to wrap it for at least one Sleep,,, then I do raise the brace as the sinew cures,, :BB
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the vet wrap does seem like a cheap and easy product to use with something like this.
More details, Pat? or an addendum to the sticky?
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If a (sinewed) reflex design calls for more reflex at the tips, than reverse bracing wants to provide,
do you wrap the sinew and bow on form all together at once?
seems like tapering the tips so that a reverse brace is profiled nice, might make for a sinew heavy outerlimb
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Nothing really to add. Just wrap it and place it in the sun and mold it into a crowned shape while it's soft.
Let it cool and gel and unwrap and take a look. Repeat as needed.
We all likely reverse brace whether we wrap or not. Logically wrapping provides much more "locking to the core" potential. You're actually providing pressure just like you would when binding lams together.
I doubt you would build a perry reflex and just count on reverse bracing as your clamp source.
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If a (sinewed) reflex design calls for more reflex at the tips, than reverse bracing wants to provide,
do you wrap the sinew and bow on form all together at once?
seems like tapering the tips so that a reverse brace is profiled nice, might make for a sinew heavy outerlimb
Not really clear what you mean. Reverse bracing isn't really supposed to give the bow more than just reflex.
The more complex parts of a profile are formed separately and the reverse brace may enhance them.
You control how much sinew goes where.
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I think I'm missing something. Correct me where I'm wrong. We want reflex so that we stretch the sinew more when we draw the bow. Why would we want to put the sinew on and then pull it into reflex? Doesn't that mean that we would use up some of that hard won reflex just getting the sinew back to it's starting point?
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I think I'm missing something. Correct me where I'm wrong. We want reflex so that we stretch the sinew more when we draw the bow. Why would we want to put the sinew on and then pull it into reflex? Doesn't that mean that we would use up some of that hard won reflex just getting the sinew back to it's starting point?
You're pulling it into additional reflex, not just laying it on a flat stave and then bending it backwards.
The additional reflex just takes ANY tension out of the sinew and helps it shrink maximally.
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The additional reflex just takes ANY tension out of the sinew and helps it shrink maximally.
Got it, thanks :D
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Ok DC I will try a lay mans exsplanation at least my under standing but say you want 4 1/2 in of reflex you reverse string the bow or a combination of natural steamed heat treated or what ever combination you want as long as it's reverse strung to 4 in. apply your layers then pull the other 1/2 reflex in to the bow after the glue gels locking the sinew into compression & the belly into tension those dimentions where just for exsample but the idea ! It helps the sinew lock to the core if you just reverse string the bow and add the sinew the belly is under tension but the sinew is not under compretion , That's the best exsplanation of Adam Korpowitz system I can muster.
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Pat
sorry, two different questions being mixed here.
1. if you use vet wrap in your work flow, do you use it as a substitute for the innertubes? or over the tubes, or under?
2.
The more complex parts of a profile are formed separately
by tillering thickness or heat bending so that the reverse brace looks good before you apply sinew?
Reverse bracing isn't really supposed to give the bow more than just reflex.
I was thinking that some designs might want to use reverse bracing in order to put the belly in tension when applying backing, so that it the belly could bend further when drawn.. perry reflex sort of thinking
forced into a form before applying sinew might be one way. wrap it form and all
also using a form for getting the reflex more towards the tips, as an alternative to permanently heat bending or pre-thinning the outers and tips
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I use it instead now. It combines both steps in one. Vetwrap is cloth and rubber mixed together.
Your other question is essentially just reaching the same result with different methods. You'll have trouble strapping a bow to a form and still being able to sinew it.
Just reverse bracing and reverse whip tillering will achieve the same result.
I doubt you're going to really notice the difference between heating a gentle curve to an outer and sinewing versus just forcing it to the bend and sinewing it.
That's putting too much emphasis on the gains of perry reflexing.
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You'll have trouble strapping a bow to a form and still being able to sinew it.
yes, I was thinking of applying then pulling it down into the form
That's putting too much emphasis on the gains of perry reflexing.
perhaps better left for a different thread or email, as your PM inbox is full
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You'll have trouble strapping a bow to a form and still being able to sinew it.
yes, I was thinking of applying then pulling it down into the form
That's putting too much emphasis on the gains of perry reflexing.
perhaps better left for a different thread or email, as your PM inbox is full
Applying and then pulling it down would probably mash the gelled matrix and tear it apart while it's too soft. Plus the sinew wouldn't be able to shift enough if you move it that much. I would probably start to squiggle on the back rather than just being squeezed slightly.
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A 1 to 1 ratio of sinew to glue is his reccomendation.On regular self bows less stressed I don't think it's that critical.Measuring myself on self bow designs or longer working limbs in paticular I think my ratio many times is 1 to 1/2 sinew to glue.Mass weight wise
How does using half as much glue as sinew seem different? Ed
for that matter, has anyone experimented to see just how much wet sinew actually shrinks, when dried, without the glue?
I painted just hide glue on a board, and it bowed from glue shrinkage alone.
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The reason I use old bed sheets is because they are thin and they breathe plus I only keep the wrap on for a few hours.
-my wife would kill me if I took her bed sheets... I wonder what would be the cheapest substitute as far as clothe?
Go to walmart or any fabric store and you can buy fabric there. I bought some linnen there the other day. I got to say if your going to buy linen at a fabric store make sure you see what it's made of. Just cause it says it's linen doesn't mean it is. Most linen fabric nowdays is 100% cotten. I had to dig through 20 or so untill i found one that was actually made of linen. However, cotten should work for this purpose of wraping sinew though. Plus cotten would be cheaper. A yard of linen was $7.
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willie....OK...I'll ask you.How thick was that glue?Did you try different thicknesses?Did you bend it to find out the difference?Did you apply sinew with it?We're talking about strength here using more glue in shorter working areas opposed to longer working areas on a limb.Thicker is stronger.Higher percentage of glue to water ratio.The difference in stress between a pretzeled dried up short horn bow to a self bow is quite a bit.Getting more out of sinews' stretching properties.
Sinew will shrink all ways as it dries but more length wise then laterally and thickness wise depending on the width of the limb.A different percentage so to speak.Adam talks about that in his book too.
I'm not down playing Pat M's wrapping method at all.Just pointing out the versatility of sinew and hide glue into different designs.To me it helps infiltrate the hide glue into the sinew well too.With the added benefit of a smooth surface so little sanding is needed or waste of sinew and the time it takes to strip and apply more.I really can't say how much actual glue leaves when wrapped and heated.Never checked.Could be it's more water than glue.Could be to ask Pat M about that.I read where he does'nt think it's ever even close to starving it if you get to read his link.
I can remember doing my first sinewed bow.I'm sure there are others on here too.I thought filling voids with hide glue in my crappy first sinew job was a good thing.When I went to tiller it to get a string on it it crackled and scared the piss out of me.Nowadays I've refined my sinewing so that does'nt happen any more.To be exactly sure of the ratio that I applied is to weigh before applying and after it has dried and adjusting one way or another.More maticulas than needed just doing a normal 3 to 6 inch reflex on a self bow with longer working limbs IMHO.
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It's all glue that comes out. The water isn't going to separate from the gelatin just because it's warm and under pressure. You'd really be hard pressed to starve the matrix. It gets to the point where it packs down so densely that the glue deep down can't get out.
Obviously I'm making it more of an art than science since I'm not measuring glue as I use it and then gathering up all the squeeze out and doing the math.
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the less glue % the stronger the layup, at least with most composites. and if it doesn't take much to properly wet out the sinew and fill the gaps, the better? I think ed and pat are both agreeing on this?
I have got hide glue in different weights. some take more water than others. it is my understanding that it is like concrete, in that adding more water to a thicker glue, just makes it shrink more when drying, and makes the glue not as strong.
if the glue shrinks more than the sinew wants too, and adds to the reflex, then that additional dried in reflex could be not as helpful as one might think.
just curious if anyone has experimented with sinew alone and maybe hoping to understand what Adam has said, without buying the book.
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I think we are but I also think Ed is saying that more glue is needed for a highly stressed short composite.
Of course Adam would need to make a bow with way less glue or wrap and squeeze to prove that this in fact would be detrimental.
I'm not going to assume that because Turkish bows were made a certain way that anything else MUST be wrong.
For a wooden bow though I do like to follow the principle of minimal glue to fiber ratio.
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nice,, I have been making sinew bows a long time and still learning and refining,, :)
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Patm ,Adam has probably did more research & experimenting with sinew/glue ratios then just about any body out there ,he went as far as dismantling ancient artifacts for dimensional purpose , those ancient bowyers where be headed if the bow failed for real , the guy is world renowned for his work I'm not saying he is the end all in the game but extremely respected when he writes some thing it's with extensive research & exsplanation I'm not saying that to be argumenitive I'm just saying if the guy writes it's because he has the boots on the ground research !
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So he did do the experiment I'm talking about? Cool. What happened?
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I dont know there Pat but you can email him and ask he is a down to earth guy that will actually respond to your email !
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I thought it might have been included in the book if you were so sure.
I'm a bit puzzled why you started this thread now. ;)
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Its in my intro nothing I have posted contrary to that !
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I just mean that if you're sure that Adam's method is the best then what more do you need?
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where can I read about that,,
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Has anyone had sinew split down the length of the limb during tillering?
I have wondered about the white streaks that appear in cured sinew and if it is too dry when they are there or if that is normal.
And, do you guys usually put your cover over sinew after final tillering or some other time.
I like the PatM method the 2 times I've tried it. I used meat wrap with the wax side to the sinew and innertubes over that and it came off pretty nicely.
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No mention of wrapping and heating in Adams' book that I've seen.
Pat...Have you ever mentioned it to him or made horn bows yourself using the wrapping and heating sinew application method for a cleaner look?
Stick Bender...As far as wrapping sinew around handles and limbs for the purpose of holding the sinew down onto a bow.To me it's not needed on a lower stressed type self bow.I'm sure it's an assurance thing when done.Nothing wrong with that either.Personal preference.It's more of a cleaner look wanted thing by some.On powerful horn bows at the base of siyahs I'm sure it's an assurance thing and probably needed too.I don't put sinew on the static tips either on self bows.No reason for it so no wrapping needed.The only reason I even put a silk wrap on at the base of a tip over a snake skin covering is to keep the loop from frying the skin up over time.Otherwise purely decorative.
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It is pretty simple :)
Wooden bows will be fine with a lower proportion of glue to sinew. However there IS aa limit and I found it by making sinew juniper bows. I a couple blow once I went too low with the amount of glue.
A few wraps too many or with a little too much pressure and you will get a broken bow for your troubles. It is common sense really. This wrapping method may have merits if you are new to sinewing but once you have done a few and tried to refine your technique it is really quite easy to get a totally smooth surface.
Wrapping would never be used on a Turkish Hornbow because the sinew needs to be flat. Adam does mention in his book that these Turkish bows sinew was never wrapped.
Somebody said earlier that composites are stronger with less glue....this isn't true I have made lots of carbon fibers parts and have a fair bit of experience making various composite materials. Excessive glue will weaken a composite AS WILL too little glue. Too little glue is actually the worst possible thing you could have happen with a composite and the material will fail well before it should have done. With most modern composites the ratio of epoxy / fiber should be 50/50. Funny.....that is the same ratio of sinew to glue.....maybe them old fellas knew something!
Pat - how many Turkish hornbows have made? You seem to not mind scoffing at the old methods and the ones Adam recommends....show us what you can do if you think you have it all worked out ;)
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I have learned a lot with this thread very interesting things going on here the funny thing is this knowledge has been around for thousands of years and is still being discussed with vigor, Brad the book in discussion is Ottaman Turkish Bows by Adam Karpowicz even if you plan never to make a composite bow the price of admission for the purchase of the book is well worth it probably one of the best books writen on sinew processes & Technical exsplanation its a heavy read & reread to retain the knowledge but well worth it in my mind, but after breaking enough bows in this game I like to use every avalable technic to my advantage !
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It is pretty simple :)
Wooden bows will be fine with a lower proportion of glue to sinew. However there IS aa limit and I found it by making sinew juniper bows. I a couple blow once I went too low with the amount of glue.
A few wraps too many or with a little too much pressure and you will get a broken bow for your troubles. It is common sense really. This wrapping method may have merits if you are new to sinewing but once you have done a few and tried to refine your technique it is really quite easy to get a totally smooth surface.
Wrapping would never be used on a Turkish Hornbow because the sinew needs to be flat. Adam does mention in his book that these Turkish bows sinew was never wrapped.
Somebody said earlier that composites are stronger with less glue....this isn't true I have made lots of carbon fibers parts and have a fair bit of experience making various composite materials. Excessive glue will weaken a composite AS WILL too little glue. Too little glue is actually the worst possible thing you could have happen with a composite and the material will fail well before it should have done. With most modern composites the ratio of epoxy / fiber should be 50/50. Funny.....that is the same ratio of sinew to glue.....maybe them old fellas knew something!
Pat - how many Turkish hornbows have made? You seem to not mind scoffing at the old methods and the ones Adam recommends....show us what you can do if you think you have it all worked out ;)
We're not talking about horn bows here Mikey. Nor did I scoff. Maybe you should try the method first. Seems you're accusing me of the same thing you're doing.
But I'm certainly not going to switch because you want to be a follower with little imagination. ;)
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yes, it has been an interesting thread... I guess if I want to sinew back my D/R, reflexed, or flat bows I will use Pat's method because I like the idea of the sinew being more homologous than those that I have made in the past. It will sure make my snakeskin look better being glued to a smooth surface. If I ever decide to build a heavily stressed Turkish hornbow, then I will definitely read the book mentioned. ...at least neither method is suggesting application with TB3... :)
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so a medium amount of glue seems to be the best,,,,wrapping or not seems to be still debateable,,?? :NN
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Keeping it simple and from a reliable source. ;)
https://en.wikipedia.org/wiki/Fiber_volume_ratio
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brad, I think it is more about careful layups.
dont starve the layup by having too little glue with too dry materiel's, or by wringing out so much "excess" that you introduce air.
avoiding too much glue is just a matter of getting your sinew on neatly without tangles/crossups/puckers etc, and filling gaps with excess glue
If I am not mistaken, I do not think that the wrapping method calls for very much pressure
check out vetwrap, very easily adjustable for pressure
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Whatever pressure it takes to get about 70/30. >:D That's probably closer to what most modern composites strive for. That's why they use vacuum bagging and autoclaves rather than just hand lay-ups.
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thats it, thats all you guys got to say,, ;D :BB :OK
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Nope Brad I googled Wikipedia & the said Jim Hamms method was probably one of the best sinew application processes so maybe I will give that a shot all kidding a side Jim has probably made more sinew bows then most , I know you personaly knew him if you get a chance could you comment on your thoughts about his sinew bows & processes ?
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Sorry Brad I could'nt help it here.I know Jims' method has started many people and in my opinion a good safe way.Which counts for a lot.Applying the way Adam Karpowizes shows is probably getting the best out of the sinew you can.More articulate and calculating but still just as safe.Just shows the versatility of the product I think.Comparing apples to oranges here horn bows to self bows though.So in the past I've heard people say how it diminishes performance etc. for one reason or another.Not if put on properly and it put in a position and shape to do it's job better besides protecting the back.It's still not rocket science to do.Just takes practice is all.Even on lower stressed self bows.Higher crowned backs versus flat backs.Short bows and long bows and different types of wood.Crowning and tapering it and laying off putting so much on the stiff tips where it's not needed on longer bows.A person can't blame the product if it is'nt used properly in the right way and I think Pat M's method is a great innovation to use along with this also.So it's all good to me and I'm just sticking up for sinew's properties is all in the end.Just my opinion again too and everybodys got one.
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Maybe the Turks could have cracked that 1000 yard mark if they just eliminated a little more glue dead weight. Alas, the invention of used inner tubes came a few hundred years too late. >:D
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Thats a good point Ed some times we discuss all the refinements of doing things & it can sound more complex then it really is , but it really boils down to which method you feel most comfortable with and what works for you but I think it is a good thing seeing all the methods available, is one method better then the other thats really is up to the individual doing it. But my level of understanding went up a notch from all the opinions here !
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Pat M....What do you mean they.....lol.You seem to be a very knowledgeable bow maker even though I hav'nt seen any of your bows.Maybe you could get them all to turn over in their grave....lol.
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Here are 2 sinew bows that I made using Jim Hamms method I temember posting on the first one saying it looks like crap & PatB told me not to worrie about it if it shoots good dont worry then the big blob of ugly looking sinew cured & it turned out smooth I really have to think Patb & others that encouraged me back then because I thought it was a complex thing that turned out pretty simple but had no idea before I did it !
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It can look like heck just after applying. :BB
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Like the posterior of an infant.
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_0884.jpg)
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Pretty smooth Pat.Love the looks of that birch bark but some put thick enough birch bark on to negate any blemishes too,but I'm sure it is'nt the case here though.
One thing about using this sinew though and no bad intentions intended here, but a person should learn to tiller a bow good before using it on bows and not to use it as a crutch just to get a serviceable bow.In fact it'll enhance the service of the sinew too I think to some degree that I can't prove.
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That's actually one single layer. Basically like a layer of paint.
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Cool.....I'm able to get it that thin too.Actually almost as thin or thinner then a sheet of paper really.I feel it'll stlll do the waterproofing just as well yet.Depending on the paper but paper is usually only 10/1000's inch thick???
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How many grains of sinew is that Patm ?
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Stick Bender,, I do know Jim,, and I made my first decent bow with him in Texas 20 something years ago,, by that time he was not making bows for sale,, or even making sinew bows anymore,,, he was teaching workshops and making mostly self bows,, mine is still shooting and I used it to elk hunt with this year,,I have made a lot of bows in that 20 year time, and nothing out shoots the bow I made back then,, as far as his sinew process,, I follow it roughly, ,and thats how I started, cause I could call or email him as I learned how to make a sinew bow, he was always generous with his advice and I owe a lot of my bow making skills to his patience and advice,, his process is definitely a good starting point,, with good basic technique,, that you can't go wrong with,, :-D. and I would say is based on his knowledge of Native American techniques,,
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How many grains of sinew is that Patm ?
I could not tell you that. "About" three layers .
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PatM... now that's what I'm talking about! That's some smooth arsed sinew right there... I like it!
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Can anyone point to the jim hamm method of sinew application? Is it in TBB series?
Comparing sinew and hide glue to modern composites and ratios may be helpful in principle, but each materiel has it's own techniques and working requirements
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It's in his book. It is the same method you will find in pretty much every sinew tutorial out there.
Keep in mind sinew and hide glue are likely the only instance of the fiber and glue being essentially the same thing.
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Thanks Pat,
Can you recall which book?, he has published quite a few.
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Bows and Arrows of the Native Americans.
The chapter in TTBB Volume 1 covers it again.
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Ed there is no question in my mind if your looking for a performance oriented sinew application Adam's is by far the best method ,pretty is as pretty dose but Bob Jims book is Bows & Arrows of Native Americans I believe I will look when I get home. I dont see why Hamms method combined with Adams wouldnt work I personaly will go for performance over cosmetic every time but really no reason you cant have both with what ever method !
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Sorry posted the sam time as Patm
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First turkish bow project. I put 2 layers of sinew already on the bow. Glue is mixture (half sinew glue - homemade, half hide glue -bought)
Waited 1 week between layers. I have used korean method; precombed thinly shredded sinew bundles, waited for glue to set and then put the wetted and heated layer on the bow. Then heated it with heat gun and wetted with fingers and some drops of water.
After glue setting again I used the compress bandage and bike inner tube to compress the sinew a bit more and to remove excess glue...
I let the bow to dry in cold place in the basement couple of days and then put it in living room...
Both 2 layers combined are 2mm thick. I plan to put one layer on the top for the finish to get around 11-12 mm limb thickness. Bow (ntn) is 48inch long.
As this is my first sinew job I dont know what I have got ...
Sinew is pretty compacted but some fissures-white lines are present... is this to worry ?
I observed the white lines through magnifing glass but actualy no cracks ...
I sanded between layers and put 3 coat of sizing glue before and in between coats.
Will the bow survive ?
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the sinew looks good,,
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I think your glue was a little too dilute meaning too much water.Not enough glue to begin with.Don't think the wrapping method did it really.Don't know for sure but I think it'll be ok yet though.I've seen traces of it on some of my sinew jobs but not overall before.Never did anything about it and never bothered much in the end here.One of those things to find out you'll have to tiller it later.Don't know either if there is a way of infusing more glue in there either.Alcohol and glue mixtiure and heating?Might not be neccessary though.I've never done it.Does'nt help you much but....someone else could comment that's seen it too and followed through tillering it.Good that you put sizings like that between layers too I'd say.Especially when heating it later.Maybe using drops of glue instead of water next time.
I've read about the korean method but have never done it.Looks like a good attempt at it though.Especially your first time sinewing.Leaves a very nice straight application.Getting the most out of it so to speak.I guess you'll end up with around 3mm or close to 1/8" thick layer with the third layer in the end then.I would make sure your last application has a thicker glue to water ratio.
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I have read about the korean method but never tried it here is one Im working on 850 grains of Elk & moose sinew I used a hybrd method part Adam Korpiwicz & part Patm vet wrap , not pretty but servicable this is a knoty sapling still have another 600-700 grains to go , it will be aprox 1400 grains total I used granulated hide glue on this one plus 6 1/2 reflex
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Reverse Brace
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Brace
Is that brace or reversed brace?
Gorazd i think your bow should be fine. Someone on Artan posted they key to not getting those streaks is to have thicker glue like was mentioned earlier. I had it on my bows and it didn't seem to cause any problems but then again they weren't that high of poundage. I think its just the different colorations of some fibers that have less glue on them (since the glue is thin its clearer and more translucent on some spots) but i'm not sure. Seemed pretty sturdy still nonetheless.
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Yep reverse brace corrected it thanks my bow is still curing only 5 days sense sinew it's down to only losing a little under 1/2 oz per day now but it amazed me how quickly it loses weight after sinew this was the first time I weight while sinew curing
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First turkish bow project. I put 2 layers of sinew already on the bow. Glue is mixture (half sinew glue - homemade, half hide glue -bought)
Waited 1 week between layers. I have used korean method; precombed thinly shredded sinew bundles, waited for glue to set and then put the wetted and heated layer on the bow. Then heated it with heat gun and wetted with fingers and some drops of water.
After glue setting again I used the compress bandage and bike inner tube to compress the sinew a bit more and to remove excess glue...
I let the bow to dry in cold place in the basement couple of days and then put it in living room...
Both 2 layers combined are 2mm thick. I plan to put one layer on the top for the finish to get around 11-12 mm limb thickness. Bow (ntn) is 48inch long.
As this is my first sinew job I dont know what I have got ...
Sinew is pretty compacted but some fissures-white lines are present... is this to worry ?
I observed the white lines through magnifing glass but actualy no cracks ...
I sanded between layers and put 3 coat of sizing glue before and in between coats.
Will the bow survive ?
Maybe, maybe not. Your glue is too thin. Also bear in mind that any 'excess' glue is only there if you add it in the first place. The real difference is that wooden bows aren't straining the sinew much, hornbows however do. Fingers crossed :)
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Thanks all !
For the last layer of sinew I will make extra thick glue.
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Obviously there is a bit different using hide glue and sinew laminations comparing fiberglassing ...
Epoxy should be very thin to better wet the glass/carbon cloth...
And Epoxy does not shrink when drying :OK ...
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Ok I tried exspermenting between Patm wrap method & Adams method this is only my opinion from trying both methods Patm method requires less skill & less prep time and is far easer to apply, Adams method requires a little more prep time & skill , I saved my longest pieces of sinew for last using Adams method the bow below has 1150 grains of sinew over 49 in. working limb & the back has not been sanded on the last layer but by using Adams method of meshing all layers prior to gelling they turned out very smooth and even for a strong bond I keeped the bow at 55 Deg 47% humidity in my shop for 31/2 days so the carbon molecules could bond in the matrix making a stronger matrix some thing the ancient composite bowyers where well aware of , I think both methods work fine but really don't like the idea of using heat after gelling it makes for a less strong bond , for a average bow the wrap method would work fine but for a highly reflexed design Adams is superior I think using his method you have more control of the glue to sinew ratio in the end of 25% with the heat wrap method you really don't know where your glue to sinew ratio ends up , I'm not stating to cause any controversy just my own personal exsperience , there is enough unknowns in this game I just prefer methods that minimize them. Also used rabbit skin glue to increase gel time.
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Sinew
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" Adams method of meshing all layers prior to gelling"
What is meshing?
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Laying them parallel and meshed together so there joined as one prior to the gelling there DC so they become one solid matrix !
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I'm still a little confused. Do you stir up the fibers to mesh them or? Do you do this on the bow or on a separate board and then move the whole slab to the bow.
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No each bundle is saturated in the glue then squeegeed with your fingers to take out the excess glue , laid on one at a time then flattened out the next layer is done the same way parallel to it and flattened out joining the 2 bundles as one before the glue gels I think there is some pics in TBB it's just these 2 processes are a variation on that !
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It also mentions in the book of using a thicker mixture of glue to water the first course if more then one course is to be put on.Sizing first done with a few thin mixture layers to get into all the little places good.Sanding inbetween.A bit more paticular with those horn bows then a regular self bow sinew job.Doing 1 limb at a time to ensure meshing like said.All because of the gelling time limits.Temperatures in the area can help control this too.The hotter the slower the gelling /the cooler the quicker etc.Don't have an overhead fan on....lol.
I've never used fish bladder glue but it's said to be slower gelling.I'm sure it is.Hide and sinew glue a touch faster but still enough time that your not that hurried applying bundles.Sometimes a mixture f both can work the best.That's why using fish bladder glue when glueing horn to core[timing more critical] gives a person more time to get everything clamped proper before it gells too much for bonding reasons.Thicker glue used then too is reccommended.Non of these paticulars are needed really doing a regular self bow sinewing though IMO.
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I think on the next one I'm going to try the multiple sizing coats and sand in between like he recommends I didn't do that on this bow just put 3 thin sizing coats with not sanding in between , even though it isn't required for a non horn bow I like the idea of getting it as close to perfect as possible , but one of the reasons I'm trying to perfect it is eventually work towards making composite bows .
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Stickbender
could you describe the compressing by pulling to reflex part in more detail? ( @ reply #8 )
Beadman
are different weights of hide glue utilized? I have three different weights
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Why would heating after gelling weaken anything? You're just re-setting the process. Also I'm curious how Adam's method yields a precise ratio? Are you using equal weight of sinew to glue and using absolutely all of the glue?
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You know Pat your right if your going to do it all at once like your method I was thinking in terms of multiple layers after a period of time but even then your probably right but as far as the glue to sinew ratio yes it is weighed if you following his method 100% at a ratio that in the end will yelled 25% to glue ratio I think it's close to 1 to 1 or as close as it can be , your method is great and easy to apply not putting it down just trying to perfect Adams method is all , like Ed said it's probably moot for these style bows just like the idea of the strongest sinew I can get but your method is far less time consuming (=)
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Pat M...yes equal weight of sinew to dried glue before water.With water to sinew mixture for a 20% to 25% mixture.Being as close to precise as a person can is the goal here.Doing enough sinew jobs will help getting that as close as possible.I like it a tad thicker then log cabin syrup but not too much.I usually don't run out and yes I try to use it all.
wilie....I stated uses of different weights for different uses.Thinner for sizing and thicker for at least the first course of sinew.
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With multiple layers the previous layer is dry rather than just gelled so you wouldn't really be re-activating beyond a very superficial boundary. That would be happening either way as you bring fresh warm glue in contact with the previous layer.
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Yes Pat your superficial boundary would be enough to bond the layers.Using a good grade of glue is all that's required.
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Pat After rethinking my comment after yours I agree I was wrong that's why threads like this are good for learning ,Willie in Adams book after the final layers are put on he states after the sinew/glue is hard but not dry that he pulls the bow into 4-6 in of more reflex less if more layers are to be put on but he is referring to composite bows , putting the sinew into compretion pushing it into the core , the part I don't understand is after the final layer is dry he speaks to sanding dusting & putting a 10% soulution of glue on just don't understand the dusting part ?
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Undoubtedly brushing or blowing off the sanded residue. The same way you would while prepping any sanded surface.
The final coat is just like what Hamm recommends after sanding the back smooth.
Sinew is too precious for me to reduce to dust as I have mentioned before. ;)
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Ok that makes sense I dont know why he just didnt say dusting off ! This bow is allready starting to pull reflex on its own again at 5 days Im going to let this one set 2 more months before tiller.
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pushing it into the core
seems odd, I could understand if it helps the sinew shrink more/better.
does he do it right after it gells?, or later in the drying/curing process?
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I think it does both buy bending the radius tighter pushing into the core & pulling more reflex offers less residents at least that's how I understand it.
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I usually end up after preweighing and reweighing things with a 1/3 to 2/3 weight ratio of glue to sinew cured on my bows these days.Good enough for me.
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willie...after it gels.
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anybody ever use something like these...
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Willie ... these rollers are for laminating the glass cloth with resin (epoxy or polyester) I think...
To get the air out of laminate.
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yes, that is the market that they are usually sold to. they work ok for getting air out, but there are better styles for bubble busting.
these rollers are very useful when working directional strands in resin. they help to orient the strands and are useful for helping to saturate and consolidate the fibers, you can apply pressure without sideways squishing . Also useful for
bringing excess resin to the surface, for removal or starting the next layer.
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Pat M...I hear what your saying about not wasting sinew and I agree and your method makes a superb finish on it.Thing is when making horn bows there always seems to be a certain little amount of thickness adjustments along the length of the limbs staged at different intervals along the limb that the maker wants before tillering.So most times a little sanding or fileing is usually always done anyway before final seasoning.Even though horn and core have been pretapered to a degree.
With self bows being sinewed those inconsistencies are tillered out with wood removal.Not the best or desired option with horn removal on horn bows.
willie....interesting tools.No I have not.I did not see those in Adams' arsenol of tools to make a horn bow but look very useful where required to use.
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I wonder if any body has noticed any difference in type of leg sinew used it seemed to me the elk sinew was less coarse then the white tail or moose sinew and seemed easer to get flattened and on , I haven't tried the horse sinew yet might give that a shot on the current bow , wish I could find easy access to some fish bladders I think mixing that with the rabbit skin glue might make for a nice mix I think Adam mentioned using cattle sinew and said it was used in some of the original bows , I also wonder if there is any strength difference between the different sinew , this sinew topic is infinitely interesting a lot of different aspects to it ?
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i think it varies from batch to batch,, if you pull a strand and try to break it , you can tell the difference in batches and in different let sinews,,, I think its age and how it was cured,,, has an effect on strength,,
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Proper preperation maybe the key.Personally I think sinew is sinew if prepared/cleaned/and dried right most times.Sinew from the ungulate species of animal would get my vote.Never hear of pig sinew do ya?
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consider all the nuances we put into the selection, collection and care of our bow wood.
there is undoubtedly much lost knowledge, about similar concerns with sinew
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when we weight train and get stronger, it's not just your muscles that change. It's also the tendons and ligaments. They get stronger too. There have also been studies that show professional athletes, in events such as the high jump for example, have much stiffer (and longer) achelies tendons than the average person. By quite a bit actually. So it goes to say that the lifestyle, strength, and size of an animal would affect the quality of the sinew we get. I would say the larger the beast and longer the tendon the better, considering we don't know their lifestyle. That is unless we raised them and controlled their activity (maybe sinew from passed away equestrian or race horses would be good? not like you would be able to get it anyway). Otherwise I would say elk sinew would be superior to deer, and moose possibly the best. But I'm not sure. cattle and buffalo is intriguing, since they are massive beasts but they don't run or jump nearly as much as deer, elk, or maybe even moose so I'd say they wouldn't be quite as good, but who knows.
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In my one-year yourney into hornbows I have worked only with ostrich, cow and pig sinew, all ahil tendons..
-pigs tendon sinew feels pretty soft and pliable in hands and doesnt feel any more greasy than ostrich/cow .... I have managed to cut out maybe 10-13cm in length max ... but pigs legs are not cheap at all - because some people eat it as specialty - and butcher sells them well !
I tested it only - glued on bamboo board
-ostrich feels a bit coarse compared to cow and pig, even more when shreded to the tiny parts (looks like thicker), I have used it for first layer in my present project...when combed with korean method - it absorbed the glue and get even thicker ? (A) more than cow sinew ! For second layer I used cow tendons... (I run out of ostrich)
I bought ostrich sinew from pet shop but there is problem with these pet food processors - they obviusly dry the tendons in heat - and you get a lot of damaged tendons (shrinked or turned into brown crystals - glue !) - I used the damaged ones for glue ...
There are pictures of dried cow tendons (actualy young beef) which I extracted.
They throw away whole leg (under the knee) - I managed to cut out the tendons leading to the finger-cave (in hoof), pretty tedious labour !
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Some interesting thoughts there the age thing crossed my mind also I know my tendons are not as good as the where 40 years ago.....lol & prep is key in my mind also , but one thing I have noticed particularly with white tail & moose tendons is there is always one tendon that the sinew is more coarse & dense almost hard and abrasive feeling , and resident to absorption , usually I set those a side & even when soaked in warm water the stay pretty much the same , I think on my current bow I will try the horse to see if it ads any HP....HaHa ! Although I will have no way to compare , but preparation Ect , the thing that crosses my mind is the Turks certainly had access to horses but used cattle among others ? Maybe a tractor VS sports car thing , this is one aspect of bow making that your left on your own more so then non backed bows as far as knowledge goes not a lot of books on the topic ! I know it's not necessary to have max stressed material on wooden ,backed self type bows but makes sense to me to make the best bow possible bow with the best performance you can get !
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Apparently at the strand level the sinew of all species is very similar. Variation seems to be more at the cross linking level which everyone wants to break down anyway. There was a lengthy discussion on this subject on Paleoplanet a while back.
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Some good reason why turks used cow/beef tendon is I think ... the quantity of sinew you get from it ... fresh beef tendons are very thick - like human fingers !
If you dont shredd the sinew in tiny parts you get 20-30 g of sinew from one tendon.
I shredded in very fine long strands - and got maybe 10g of longest ones of it - exactly for one combed sinew layer (one bow limb),... and lots of small pieces for ears covering (ot glue making)
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PatM ... when doing sinewing I used your style (with bands and sheets) + korean style ...... puting the combed bundle then overlaping the next one about 5cm ... but I noticed that on the overlaping place I have got a step and had problem removing excess glue under the first bundle in overlap....
On second layer sinewing (one week later) I compressed (only with elastic bandage) each combed bundle - wait an hour and then did the overlap. Now the steps are not visible on overlap places .... will see what will be out of it
I plan my third layer on this weekend.
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I've never used beef leg tendon but would'nt shy from it.I've used long beef and buffalo backstrap.I'm not surprised as to beef tendons' thickness.An ounce of stripped sinew from a tendon is pretty good in my world.
I always try like heck to get that Y seperated on leg tendons right off the bat for more longer strands.Does'nt always work but lots of times it does with some persuading.Always have use for the shorter ones too.Even 3" long.
Good luck with your bow gorazd.
Made some sinew glue the other day in a pot from my scraps.Ended up with 4 ounces of first pouring dried glue.Did'nt pour it thick enough to gell.Only 1/4".Next time a good 1/2".Cut a criss cross pattern ended up with what I call corn flakes.They'll dizzolve quicker in water and work though.
Poured it into tin foil cookie and cake pans.Gelled some after an hour but not enough to cut up.Put it in frig and it gelled quickly.With spatula took out little squares of gelled glue.Laid it on a sheet of thin garbage bag cut open to make it large on a table.Took a couple days to dry hard though.Does'nt stick too bad to that thin plastic at all.
Theoretically should be enough to do at least 3 bows.I hope.
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Beadman
when making sinew glue, how do you tell when it is done cooking?
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I first soaked my sinew a good 12 hours before heating it.You can add a little lye to the mixture to break the sinew down more but need to rinse it then too.I stew the sinew in enough water to cover and then some at 170 degrees F for a good 12 hours with no lid on the pot at least for a first pouring of glue.It's supposed to be the best.You can stew it 24 hours for more by adding more water.Too hot will weaken the glue so don't let it go above 170 degrees F. and if the water is not rolling be sure to stir it every half an hour.Otherwise a film of glue will develop on top and your glue will get too hot.I just glanced at Tim Bakers' way in the glue chapter of TBB book.
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Glue---TBB1, thanks
so different qualities of glue come from different "pours"? Do you find working differences in addition to finish/strength qualities?
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What's said in the book I think is right.Hide glue of any pour should be good enough for self bows.The more sinewed bows you make the more you know.I've personally never seen hide glue fail yet or a bow fail because of the hide glue.
The differences are told in the smell of it when preparing.If it stinks bad it's no good.If it smells rather pleasant at least to my nose it's good.
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And you can add onions and make soup ;D Is there a limit to the number of pours? How do you know when to stop?
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It is edible or it won't kill ya anyway.I could'nt tell ya if there's a limit.I'm sure there is.2 pourings is enough for me.It's kinda of a long process.
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I would have to be pretty Hungary to eats some , I'm going shopping with my wife tomorrow to suburb a couple towns over that has a korean market I'm going to stop in and see if they have any fish bladders does any body know what kind of bladders are best ? One of my coworkers told me you can find them in health food stores but have never seen them there.
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You know that's a good idea to do Ritch.I'd like to have a little fish bladder glue around myself.Need to go to the city I quess.Catfish,gillbacker,and croaker air bladders.I'd take the TBB 1 book with and show them the picture in the book.Good glue ought to be able to gell even at a low concentration within an hour in a frig for sure.Otherwise it's no good.
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StickBender : about fish glue
I have managed to extract good glue from catfish bladders . Catfish is pretty common fish in rivers and lakes here in Europe and grow big ... 10 or 20 kg catfish is pretty regular catch in summer...
On first pictures is bladder from 15kg catfish ... bladder is around 20cm long
Second picture dried bladders...
I cook and chopp them in blender and cook them again ... .all about 6-8 hours- yield is pretty good I guess better as in doing hide or sinew glue
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From what I read on google though fish bladders can be hard to get maybe even illegal.
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Beadman :
Catfish has no natural enemy - and is not protected in countries in Europe (as far I know)...
Fishermen catch them quite often and is seen as biggest predator.
Meat is good for eat - but bladders are thrown away - I have contacted them and they spare the bladders for me when there is some catch ...
Try to contact some local fishermen ... You have big lakes/rivers in USA and there should be huge catfish for sure ! ::)
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Gorazd that's a pretty nice big cat you caught there good info maybe I will get my fishing pole out and try some around here again I use to have real good luck using congealed chicken blood worked really well Ed I will let you know if I have any luck bet I could find them in China Town down town it's a big area here in Chicago lots of those type stores Gorazd did you ever do any mixing of the fish & hide glue or what is your exsperience with gel times & use Ect ?
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I wouldn't be surprised if most bladders will make good enough glue. A lot of "trash" fish have a good sized bladder too.
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Maybe this thread should be renamed "Let's talk about everything composite bows" ;)
Seriously though, good discussions and nice thread
(-P (-P (-P
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Yes I've catfished abunch in the past here.Just ate them though.Flathead and channel both.Had a big grass carp die from a freeze out in a pond a few years ago.I should of kept his bladder.I kept the skins.
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Aaron H....I feel it useful on any type of bow really.
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That illegal stuff might be about sturgeon air bladders.
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You're right Ed, I guess it still applies to self bows
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StickBender:
Yes I mixed the home made fish bladder glue with hide glue when gluing the horn. Worked well.
I Tested the strength of mixed-glue (with which I glued the horn) - glued two pieces of black locust - with no pre-sizing (!!!) ...after one week I made hammer test- slashed hard and tried to separate two pieces of wood - and glue held... wood teared out!
When I have done gluing horn - I sized (both horn and wood) with pure fish glue ... Sizing coats stayed wet quite long - I heated the wetted horn and wood part with fan non-stop during sizing process - 20 coats
Then add hide glue to thicken the glue mixture... and put thick coat of this mix-glue before joining horn and wood .... gell time of this mixture was a bit quicker than pure fish glue for sure but managable to do the joint
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Use the carp bladders and do the world a favour too
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You might be right Aaron H.
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Very cool Gorazd there's some pretty good size channel cats in some of the rivers around here ,maybe give it a shot , but for regular wood bows I really like this Rabbit skin glue that Ed recommended but if I could get some bladers to add could probably get a little more gell time to get all layers down before gel , the liquaid hide glue allows for that I have used it in the past with good luck I know some have not had good luck with it but I have never had a isue , this glue topic is as interesting as the sinew (=)
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I think as with sinew glue avoiding grease is the same when going after fish bladder glue.
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Rabbit skin glue is not known as one of the better ones for structural purposes. Hard to beat Knox for all around quality.
If you're going to buy rather than brew I would just go that route.
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Pat I have never used the Knox , what kind of time do you have before gel with it ? What I like about the rabbit skin glue it gives you a pretty fair working time !
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Gel time never concerned me. ;)
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Too thin of sinew is less desirable right? It can lead to white streaks on the sinew. Is this because it takes longer to gel? If so, longer gel time may not be good (unless you're applying horn?) so fish bladder glue, and rabit glue may not be better than regular hide glue for applying sinew. It still should work well though.
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The truth is wildly different performance levels have beeen achieved by different sinewing methods and glue types.
I do know that a guy who claimed to do the best sinewing achieved pretty mediocre results on the Salt Flats. Not even 300 yards!
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Truth is I've used the Fredrix type rabbit hide glue many times.It's never failed me.With excellent results witnessed through the chronograph.I'm not a name dropper but it's been used by someone else everybody who's been on PA forum for a while knows,but I'd have to agree hard to beat Knox too.Just as easy and available.
Nothing like making your own knowing what's going in it.
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Apparently at the strand level the sinew of all species is very similar. Variation seems to be more at the cross linking level which everyone wants to break down anyway. There was a lengthy discussion on this subject on Paleoplanet a while back.
All sinew is made from the same stuff, this is true. When sinew increases in strength i'm not quite sure what is actually going on. Do you have a link to that paleo discussion? I think that would be interesting. I'm not sure if its just more collegen fibers connected together or something else as well. It can't be just the connections holding them together since that wouldn't increase the longitudinal strength. If it is simply more fibers then it doesn't really matter, because we break them down anyway like you said. However, according to the sources on wikapedia its not just strength that can change but the stiffness too. That can't be accounted for by simply making more fibers. The mechanical properties of tendons vary widely, as they are matched to the functional requirements of the tendon. The energy storing tendons tend to be more elastic, or less stiff, so they can more easily store energy, whilst the stiffer positional tendons tend to be a little more viscoelastic, and less elastic, so they can provide finer control of movement. A typical energy storing tendon [the achelies for example] will fail at around 12-15% strain, and a stress in the region of 100-150 MPa, although some tendons are notably more extensible than this, for example the superficial digital flexor in the horse, which stretches in excess of 20% when galloping. Positional tendons can fail at strains as low as 6-8%, but can have moduli in the region of 700-1000 MPa.
What's interesting to note is the ranges. The non energy storing tendons are still much more elastic than wood (which is about 1%) so the strength really is a non-issue. What matters more is the stiffness. Surprisingly these sources are saying tendon is much less stiff than what other sources were saying. Much less. But it is intersting to note that non storage tendons are stiffer. That makes me wonder if backstraps are stiffer. This varability in stiffness indicates there is something other than the number of fibers. The only thing i was able to decifer was in these quotes: The mechanical properties of the tendon are dependent on the collagen fiber diameter and orientation.
mechanical loading has also been shown to stimulate fibroblast proliferation and collagen synthesis along with collagen realignment
the mention of realignment and orientation suggests to me that these are factors that account for verying stiffness. And its not just between different tendon types but as i mentioned earlier, training (specifically jumping and sprinting) leads to stiffer tendons aswel. This is known to occure, I specifically remember reading about it the the book Sports Genes, which was a required reading for a class in my major.
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Don't lose sight of the fact that we use dried tendons. Surely that changes the observations done on living specimens.
With sinew backing I really think you have to consider your end matrix a whole new substance.
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Can anyone share what they have learned about differences between working times for the various glues mentioned?
fish
sinew
first pour
second pour
hide
bone (knox)
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Sense were speculating why, I was googling different aspects of animal glue particularly fish & Rabbit but I was thinking strength wise maybe it has to do with how pourious the different types of tendon sinew & how it's processed thin combed Ect are ,and the glue used, if a tendon is able to absorb more moister glue/water and the glue used is a slow gelling type (fish) & the matrix is able to stay as plasticized as long as possible allowing allowing the carbon molecules to wiggle in place maybe increases the strength at a molecular level sense the strength springiness is a composite of time ,material & glue Ect , the ancients new to keep the composite as placid as long as possible the Korean bows where made in the winter months to keep it placid as long as possible with out spoilage & long cure times some of those bows after hundreds of years the sinew strands where almost undetectable when dissected ,it was so complete as a matrix , I often think those ancients didn't have google & iMacs but there life's & there family's life's depended on producing quality products there is a reason why they did things the way they did ! I think maybe your right Aaron H (-P
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ok Its getting over my head ,, whew,, seems the slow cure is effective, thats awful, cause I hate to wait on that stuff,, every time I think i am getting patient, theres a new issue to be more patient,, :NN
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I trying a exsperment today Brad to really slow it down per time Baker Im adding organic vinegar to the Rabbit glue trying to make liquid hide glue also out hitting some of the asian store trying to find fish bladders , Patients is a virtue remember :BB (=)
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Brad....For self bows cutting these fine lines I don't worry but for horn bows???Making enough of them with success and failure usually tells the tale.If things hold together good if not have to relook at how it's done or materials used.Contamination can be one of the main reasons for failure too.Grease/oil/dust etc.
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Maybe I'm getting a little over the top on my quest but what I'm after is nothing more then extending the gel time on the glue so I can get a picture perfect looking sinew job that's strong & no sanding needed when done & all strands meshed together before gelling ,when I have used commercial grade liquad hide glue in the past it was easy to obtain that but you hade to track down a fresh batch from the manufacture & test prior to use I think I have found the solution will publish later !
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You are likely weakening the end result by adding stuff.
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I'm using nitrogen Pat most of it evaporates as the joint cures and what's left is fairly inert the strength can be adjusted threw viscosity but I'm using it at such low concentration it probably won't make a difference but I'm running test on it now also going to try it with Knox , that's why I'm taking the action to test it rather then just assume it before using it !
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seems the slow cure is effective, thats awful, cause I hate to wait on that stuff
is gel time and cure time related? I thought gelling went hand in hand with temperature, and cure would be the long term drying that might be more dependent on humidity?
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I spent a good part of the week end exspermenting with glue looking for extending the gel time on rabbit skin glue , I reread Tim Bakers chapter on glue in TBB 1 so I thought I would start by trying adding vinegar to the mix trying to exstend the gel time of hot glue I got up to 62% vinegar to the liquid portion per volume of the mix it failed never could get it to extend the gel time ,the glue acted the same as with water , next after reading articles on 17th century furniture makers to modern musical instruments repair & manufacturing it was interesting stuff really, I found out about adding urea(nitrogen ) to the glue commercial liquid hide glue manufacturers add up to 25% by weight to glue to keep it liquid so I got a hold of some commercial grade 45-0-0 urea and starting by adding 2% by dry glue weight of urea it did slow it some but wasn't what I wanted so I worked my way up to 5% Urea , Bingo it was what I was working for ,as a test I re sawed a peace of osage I didn't degreased it or size it intentionally I took the amount of sinew that I would normally put down as a bundle and soaked it in water for 1/2 hour took it out squeezed it out swished it into the 118 Deg glue and purposely squeezed out a lot more glue then I would normally do I wanted the glue up to be weaker then normal after laying the bundle & flatting it out I was able to adjust the bundle for a full 14 min. at 72 Deg's after that the glue would start soft gelling I could probably extend that at higher room Temp. I was able to get the strands down paper flat & strait , I'm going to do a bend & break test after 2 weeks cure to see I will post it then. This is not a formula for liquid hide glue but if you up the amount of urea it probably would be ,the formula I ended up with by weight for the viscosity I wanted was glue to water ratio of 1 to 1.5 + 5% 45-0-0 Urea of glue weight , I added the Urea after the glue/water was well mixed & hot and re heated after urea to 118 Deg before use .
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That's what the "old brown glue" commercial brand is....
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Yep I think most of those liquid hide glue manufacturers use it but in much higher concentration & I think they use standard hide glue that's 192 gram/strength this glue is setting around 251 so even if the urea degrades it to 245 it's still stronger then regular hide glue but it really doesn't make a difference 192 TG will pull wood off before the glue breaks I'm going to try it next with Knox
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Willie I was hoping some body would chime in on some of the glues you mentioned my only experience is with hide glue,Rabbit skin, and liquid hide glue as far as natural glues but maybe the following will help this is info that I found threw research , the molecular composition of hide glue is
Carbon 51-52%
Hydrogen 6-7%
Oxygen 24-25%
Nitrogen 18-19%
Total 100 %. It's soft gel strength is rated in gram strength usually between 80 to 250 for practical glue ,the higher the number the quicker the gel ,for general purpose hide glue is usually 140-250 GS all the natural glues are rated under that system Hide Glue (Including Knox) being the highest in the chain and fish & fish bladder glues being the lowest , but those numbers can be deceptive because it gives you the impression that the higher number would be the stronger glue but it has nothing to do with the cured strength of the joint only the soft gel density & the molecular weight , 80 GS glue will pull wood off before the glue breaks so like Tim Baker said the lowest grade Hide Glue will work , but just because the sinew won't pull off the bow is not the whole story , the way the glue primarily works ,in the way I understand it is most of the strength comes from the big players Carbon & Hydrogen bonding & the oxygen & nitrogen being minor players but the vast majority of the bonding occurs while the glue is still placid so the slower the gel & the slower cure the stronger the joint that's why fish glues end up being the strongest even though there not as dense as others , I'm no expert or trying to be just sharing what I have learned but understanding how & why the glue works has me rethinking how I do things for a better sinew job !
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Stick
maybe I should have presented the question a bit differently. It is a bit of a stretch to think that someone would be able to cite experience with all the different glues that were listed.
I have read that fish glues gel slower, but beyond that, it's hard to tell glean about the relative working times. Maybe folks could share the differences between the two or three they have tried?
I thought knox was bone glue?
Seems that maybe my other question about drying times might be too subjective to elicit a qualified response also.
What do you think the best way to tell if the glue/sinew matrix is cured. Can you weight the bow for weight loss, with any accuracy, like you might when drying a green stave?
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I don't know exactly what goes into Knox I have read bone & pig/cattle skin , I don't think weight is a good system for judging cure because I know with my current curing bow after the first 2 layers & 2 weeks of cure time the weight loss slowed to a crawl the only way I know is time & RH I'm letting my curent bow cure for 2 1/2 months or longer, curing sinew is a whole different thread I have herd so many different cure times it also depends of the amount of sinew used & how thick ,my bow I used 1150 grains in only 49 in. working limb if you start to soon like after 1 month you some times will have to re tiller over time Adam actuly has a chart in his book for cure times !
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Lots of off shoot subjects connected to the main subject of sinewing processes with the different glue types and sinew types.I'm defeinitely no expert either and usually always try to get a common denominator from different sources of info to come to a decision on things.Like Ritch said the slower the time it takes for all those molecules to align themselves during the gelling stage does help in strength for the cure and strength.
In other words a person should let the freshly sinewed bow gell and partial cure in a cool place at least the first couple days.
You've gotten more info on the subject Ritch then I knew about the percentages of different molecules in glue,and a good explanation of what ones are most important.
Personally I'd like to have a little air bladder glue around to mix with the sinew glue for better moisture resistant and strength qualities.After sinewing using a tannic acid solution glue from tree bark for a sizing over finished sinew for water proofing reasons.Possibly smoke the bow too.Besides putting a birch bark or snake skin cover on too with tite bond 3.All of these steps and barriers I'll call them[air bladder glue mixed in/tannic acid based mixture hide glue sizing/smoking/and birch bark to get a sinew job that's more then strong enough with moisture reisisting qualities.
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Cool temp speeds up gelling though. if you think prolonged gel time is beneficial you would be wrapping the bow to keep it in that state.
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Yes cooler temps promote quicker gelling.Wrapping and heating if done would reliquify to regel later for wraps to be taken off.
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This bow I left in the shop after gelling for 3 1/2 days I got lucky & we had a 4 day rain storm & the bow stayed at 48 to 54 Deg 51% RH & the gel was still softer at that point it keeped it from drying fast it's been 2 weeks sense last layers & 4weeks sense the first 2 layers and it's pulling 6 1/2 in of reflex on it's own I'm going to let it cure another 1 1/2 months !
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the slower the time it takes for all those molecules to align themselves during the gelling stage does help in strength for the cure and strength.
In other words a person should let the freshly sinewed bow gell and partial cure in a cool place at least the first couple days
just thinking out loud, but if slow cures make a difference, then maybe not drying , and shrinking the sinew too much to begin with, would also help? Has anyone tried to freeze it for storage, and dry just enough to shred before using?
Any info on primitive sinew collection and prep out there? I have been looking thru some old Smithsonian anthropological and materiel culture publications, and find much about the collection of objects, but little on observations of methods.
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I don't think it would suck up any glue in that state I have never herd anybody doing it !
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Why does it have to "suck up" the glue?
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I would think for solid bonding ? But you could try it & see , but I would think if there was a advantage it would have been done some where ?
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Yes, I suppose that it would need good bonding. That is usually accomplished at the surface boundary. I think that's what the slow cure helps with. In general, there are some myths about the benefits of a glue to be able to "penetrate", but that's beside the point. My thought is, good bonding is only good until things start unbonding. It might be beneficial to have a glue and sinew that shrinks at the same rate in order to maintain a good bond. I would be interested to find out how people who used sinew tools everyday of their lives, worked with their materiels. To frame my question a bit different, can anyone point to a primitive source that indicates drying the sinew hard was a necessary part of making the magic happen?
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You can just soak sinew and pull it apart while it's wet. The drying is for preservation to a large degree.
Pounding it makes it fray to a degree, but stripping excess glue largely makes all those potential links run back unidirectionally.
You will actually find multiple methods of sinew application across the globe with similar end results.
Some of them don't even involve soaking the sinew in glue but rather laying them on glue and painting more glue on top.
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The one that surprised me was the glue "crayon" that they scrubbed on the bow and then laid the sinew on that. Page 166-167 TBB1.
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I defintely need to start a bow before I forget some of this,, :)
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Don't worry Brad it's mostly over 60s crowd here well have to start it over in a week so we don't forget >:D
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Perfect timing for a thread like this for me, just started my first sinew job. PatM, first of all thanks for sharing your techniques, I've read that stickied thread a few times. I have been attempting your technique using vetrap and it is sweating glue out great, but I am having trouble with it sticking when I try to remove it. I thought maybe I was not getting it hot enough, but then when I used more heat it seemed like the wrap was shrinking/melting. If you have any advice for me, I would be grateful.
Thanks to all for such an engrossing discussion.
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Perfect timing for a thread like this for me, just started my first sinew job. PatM, first of all thanks for sharing your techniques, I've read that stickied thread a few times. I have been attempting your technique using vetrap and it is sweating glue out great, but I am having trouble with it sticking when I try to remove it. I thought maybe I was not getting it hot enough, but then when I used more heat it seemed like the wrap was shrinking/melting. If you have any advice for me, I would be grateful.
Thanks to all for such an engrossing discussion.
Try sponging off the squeeze out right away before you let it gel and then try to peel it off more gently after it gels. Try not to let it dry. You can hold the sinew down by hand just to give it a bit of help while you peel.
I might have to add some video how to...