Primitive Archer
Main Discussion Area => Bows => Topic started by: ionicmuffin on July 14, 2013, 02:28:34 pm
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Ok, so I have a quick question on sinewing a bow. I would like to get 2-3 layers on depending on how much reflex it takes but I really only have like 1.5 weeks before I'm off to college. Should I wait until I come back this winter to do it? I still have a lot of things that I have to do to get ready to leave anyway but I think I could get a few hours in. What are your thoughts? btw the bow to be is an ERC at about 50-55 lbs at 28" currently and has about 1.5 inches of set.
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I would put all three layers on one right after the other and then put it up to cure while you're away at school. When you get back,it will be ready to tiller. Don't expect it to pull itself into reflex on your first sinew job. You might think about a cradle to tie it into to induce whatever reflex you want. Josh
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I would put all three layers on one right after the other and then put it up to cure while you're away at school. When you get back,it will be ready to tiller. Don't expect it to pull itself into reflex on your first sinew job. You might think about a cradle to tie it into to induce whatever reflex you want. Josh
+1
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That's a great scenerio you've got there.I'd put two layers on a week apart from each other.You can put it on all at once too but I like to even things out really nice between courses sanding to have a nice finished job.Nice straight and even to get the best from your sinew.Let it set while your at school to fully cure.The bow will be fine.If it's got 1.5 reflex right now you'll have a little more reflex when you get back.Even more if you reverse brace it a couple more inches.Your poundage estimate I can't say because I don't know what it's floor tillering at.I'll say this though that if you put two layers like I said it'll gain at least 10 pounds of draw weight.That's with the layers of sinew completely covering your limbs and even more if the sinew is crowned on the limbs.There is more to this sinewing than I care to get into right now but that's what you'll get above described for sure.
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I hafta ask, if you already have it drawing 50#@28", why do you want to sinew it? Josh
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The last bow I sinew backed I put three layers on at once to save time. I had some problems with how the sinew dried and pulled. It took me a lot of time to fix it. From now on I'm putting one layer on at a time.
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+1 Gun Doc but is he saying that it is already finished at 50 to 55 pounds.Personally if I'm pulling it to 28" and it's holding up and I've taken my helmet off I'd leave it be.Especially with 1.5" reflex yet.Sounds like a good shooter to me.
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I think we need to use different terms when referring to sinew backing. Especially to those who are new to it. I am no expert on sinew backed bows so take it as that. If you do it by weight I feel you can get it more evenly distributed per limb. I also think that too much at once is not really good. If you are doing it in "layers" do it one at a time. If doing it by "courses" do a heavy one then something down the crown of the bow's back. I think Clint is right about using too much at once it doesn't cure properly. The outermost sinew cures or dries faster than the inner and causes problems. I have used thicker "bundles" on the last couple of bows I've done and I think it makes for a nicer looking job. This doesn't necessarily help your question about ERC sinew backing but maybe it can help with future sinew jobs.
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+1 Gun Doc but is he saying that it is already finished at 50 to 55 pounds.Personally if I'm pulling it to 28" and it's holding up and I've taken my helmet off I'd leave it be.Especially with 1.5" reflex yet.Sounds like a good shooter to me.
Lol! I squirted coffee out my nose on the "taken my helmet off" comment. That's funny I don't care who you are! Josh
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You have plenty of time to get it done before you leave and still time to prepare for school. Have everything ready before you start so the sinewing goes smoothly.
I'd put down two or three(if you have enough time)layers but one at a time. You can add the second a few days later or as soon as the first looks dry(big color change). You also have the perfect senerio as far as tolerating the wait of drying sinew. ;) Once you get the sinew on the bow place it in a dry spot with some air movement but be sure it is away from pets and pests. I let the sinew backed bows I make rest over the hot water heater in our utility room; out of sight, out of mind. You will have plenty to distract you between now and the time you get back home. The bow should be ready for final tillering then.
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So that's how it's done Pat.... ;)Out of sight out of mind.I'll have to try that.Usually every morning while I'm having coffee I set it on the table to goggle at it.
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If I did as you do, ED I'd for sure mess with it and screw it up. Don't ask how I know. ::)
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I hear ya.It has happened. :D I'm getting better at leaving well enough alone now though.I try to look at the big picture.How's your static curve doing?That should be up on the board pretty soon.
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Would like to know the length of icons' bow though.Need some more facts about it talk about it.
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do you have any of the sinew shredded yet ??
that's a couple hours work in itself....
I will go on to say that nearly all of the sinew backings that I've done have been applied all at the
same time. sometimes there are gaps to fill in later but that only takes a limited amount of time compared
to the initial backing.
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Mid August for the static, Ed. It is out of sight... ;)
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I have no problems letting my sinewed staves sit to season...heck...I still got an osage that was sinewed over two years ago now still waiting to cure out to be tillered ;D ;D :laugh: 8)
I'm in the ole school camp of letting your sinew "season "....so it sounds like a perfect scenario of sinewing now,then tiller it no sooner than Xmas break...or even next summer 8)
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I like to sinew in winter and tiller in summer.
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Ok, so to answer your question Beadman: The bow is 60 inches ntn, it has 1.5" of SET! its about 1.75" wide and about .5 inches thick, its limbs narrow 9 inches from the tips. down to about .5" as far as the "why sinew this bow" question. It has a ton of violation on the back of it right now, I decrowned it with the intention of sinewing it anyway. Its held up to tilering on the tree but has yet to be shot so I cant say I'm out of the danger zone yet, so I would like to sinew it for safety and also so I can add my snake skins to it. Like you guys said, it's a great opportunity for the get it out of sight and out of mind because literally I will be out in wyoming so I wont even be around to see it at all let alone have time to think about it.
I can post pics this evening if you all would like to see it but until then this is what I've got for you all to go on.
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I'm no expert but this is what I do with a bow like that first of all cut it down to 52" (if it bends through the handle) then, string it backwards do one layer wait about two days do the next layer , wait again, then do your final layer, wrap with tape (sticky side out) for a couple hours, come back to it in winter. you should easily get rid of your set if not reflex it a fair bit, as far as weight goes last time I did a bow in that ranger with three courses I couldn't string it after it cured, with that one though I didn't string it backwards before sinew so with the extra reflex you could gain more.
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Why decrown the bow for sinewing? ??? I've never decrowned any bow in over 25 years of wood bow building.
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Are you happy with it? if so, don't mess with it ;)
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I decrowned it because it was a high crown and I wanted a flatter profile, especially one that was wider and flatter than some of the others I've made. I didn't really know exactly what i was doing but i figured if i was going to put sinew on and all that i would decrown it where i wanted to. I also did this so that the wood that is purple would show up on the bow rather than all sapwood.
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There is rarely any need to de-crown. Maybe on tension weak woods that you want to be a self bow but otherwise an untouched back is the safest way.
With sinew you really want it to be as crowned as possible.
Put one thin layer over the whole back and let it dry a couple of days.
Next layer should cover only half the width and let dry for a few more days.
Then the last layer should be just down the center.
Really it's best to stop tillering a stave before it takes any set and then sinew becuae your bow has 1 1/2 inch of set then it will never regain that 'spring' from undamaged belly wood no matter what you back it with.
Also remember sinew is heavy compared to wood. It's sg is around 1.3 so you have to make it work. Sinew can stretch upto 8% of it's length wood only 1%. So if you think about it you are adding a heavy material onto a piece of wood that limits how hard it can work to way below it's maximum......all these points add upto - use sinew on short wood bows :)
It's very very easy to make a sinew backed wood bow slower than if it was unbacked and designed properly.
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Whatever you wanna call it(decrowning or not)...I find it best to remove most if not all sapwood with woods like junipers and yew if I'm going to sinew them,and leave a bit of a crown still....and the op did exactly that...just cause he used the word "decrown" means that he actually did what folks are interpreting as "decrowning"...it seems like so many folks bash and despise that word so much that whenever someone says it folks go off like bottle rockets...lol :laugh:.....and IMO "real" decrowning is no harder than chasing a ring and actually easier IMHO...yet we chase a ring and don't "bash" that and emphatically advise to do so....I think y'all just misinterpreted the usage of the ops word "decrown"...because I know y'all who's so anti decrowning would've done the same thing as the op did as far as removing sapwood to have a sinewed heartwood belly ;)
Also making a flatter back might have been needed to allow the proper width for the design at hand...you can only go so wide with a small diameter stave..and creating a flatter back allows for more width if needed ;)maybe the op needed to do it because of this as well...and although he bent it to far presinew,he still had the intentions of sinew backing it..so who cares if its violated n such
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Like I said, I really wanted it to be a heartwood sapwood combo because otherwise it would have been entirely sapwood. Plus the natives used to make sinew backed bows that were very flat on the backing as well, not super flat but flattish, I realize that those bows were shorter but they also had a shorter draw. My intention was to get another inch or so out of the draw so as to be drawing to 29" or so, that would allow for maximum usage of the wood right? so if it were sinewed as well then it would allow for more efficient sinew usage. I'm just thinking out loud here, I don't mind having the minimum sinew on this bow since that was my intention all along I am more than willing to put on a very thin coating of sinew, so basically the finest sinew strands possible for maybe 2 or 3 layers so as to still have the sinew but will still be relatively light. I also desire to have the experience of sinewing a bow.
Whatever you wanna call it(decrowning or not)...I find it best to remove most if not all sapwood with woods like junipers and yew if I'm going to sinew them,and leave a bit of a crown still....and the op did exactly that...just cause he used the word "decrown" means that he actually did what folks are interpreting as "decrowning"...it seems like so many folks bash and despise that word so much that whenever someone says it folks go off like bottle rockets...lol :laugh:.....and IMO "real" decrowning is no harder than chasing a ring and actually easier IMHO...yet we chase a ring and don't "bash" that and emphatically advise to do so....I think y'all just misinterpreted the usage of the ops word "decrown"...because I know y'all who's so anti decrowning would've done the same thing as the op did as far as removing sapwood to have a sinewed heartwood belly ;)
Good catch on my wording being loose, I think that what i meant to say is that i basically didn't follow a ring but i didn't make it flat. I put as much heart wood in the bow as possible because it was a small stave there anyway, but for what its worth it should have an almost entirely heartwood belly with some nice creamy sides and handle.
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I see.Sounds good.Oughta make you a very nice and safe bow,and you have time.