Primitive Archer
Main Discussion Area => Bows => Topic started by: gfugal on October 04, 2017, 11:44:06 pm
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How much sinew in weight do you use when sinewing your bow? I'm trying to decide if I need to shred some more. I have 3.5 oz partially processed as of now.
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You have about 1500 grains there if my math is right, not knowing what bow your putting it on or how many layers your thinking makes it hard to answer , but 1500 grains is plenty for most sinew bow !
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That depends a lot of drawweight and length of the bow ...
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Ok here's what I found by going through older posts.
I am lucky enough to get elk leg sinews 20-25" long. Each leg sinew yields between 25 and 35 grams of processed sinew. between 1 and 3 will back a bow with perfect long 20+" bundles. I just finished backing a 47" bighorn bow. 3 applications over 3 weeks. 142.5 grams. Over 5 ounces on this bow. Some smaller deer leg tendons will only yield 5 grams or so - loefflerchuck
So 25-105 g / 385-1620 grains / 0.9 - 3.7 oz
60 grams – mikekeswick
so 60 g / 925 grains /2.1 oz
I have heard it takes 16 [deer] legs - wood_bandit 99
So 1 leg = 5g (according to lofferchuck), 16 = 80 g / 1230 grains / 2.8 oz
About 10-12 decent length [deer?] back strap sinews will give you a solid 3 courses. - PEARL DRUMS
I'm assuming 10-12 back straps is similar to 16 leg, so similar to above
as suggested above,, about 400 grains on each limb should be enough,, you can weigh the deer tendons whole and get an idea how many it will take,, I have weighed the elk tendon whole and then processed it,, and it is close,, you loose a little to waste when you separate it to threads,, for best performance, you want least sinew to hold the most reflex,, :) 1 oz is about 420grains,, I guess you could put 2 oz on each limb on a bow that long,, but it does seem like alot,,, - Bradsmith 2010
So - 56 g / 875 grains / 2 oz
OK oak walker.I can usually get close to 400 ounces of usable sinew out of an elk tendon. All in all sinew is sinew No matter where it comes from I think.
Weighing it is the proper thing to do when it's ready to be put on. It's all relative here. On a 62" bow being sinewed 2 ounces per limb will be a whole lot. Never done that much.I know half that will do the job, or an ounce per limb. 4 ounces is at least 30#'s worth of draw & that's relative too. Don't know how much reflex you want. With that much you need a lot of reflex to make it work for it's money.Need more info to answer your question. – BowEd
Same as above
IMO no more than one light layer on a bow that long [66'] if you are set on doing it. If your bow gets too long the added weight of glue and sinew outweighs the benefits of adding it. A longer bow with a troublesome back would be better suited with a rawhide backing. If you want to add sinew for performance reasons only, I suggest a 58-62" tip to tip bow with 2-3 layers as Bryce suggested.. - PEARL DRUMS
Deducing from the earlier quote from him I'm assuming 80 g / 1230 grains / 2.8 oz gives 3 courses. So 1 course would be 26 g / 410 grains, 0.93 oz.
When we say courses it means layers. Most people apply sinew over the entire limb but I do not. Many years ago I did some thinking on the subject matter and I deduced that it was not necessary to apply sinew that way. What I started doing was to apply the sinew to maximize it's use plus keep the added mass as low as possible. I figured that a limb does most of its tension work down the center where you have a crown and that the outer parts of a bows limbs do very little work. I knew that sinew is more elastic than wood so it could stand to have a high crown. What I therefore did was to apply no more than 1 course along the edge and the outer limbs. Then moving were 2 courses progressing to 4 courses down the center of the limb. This produced a higher crown, almost like a cable of sinew down the center of the limb. All of the bows I sinew backed were short, highly reflexed static recurves and they all shot into the 180 fps with 10 GPP arrows using dacron strings. I'm sure that with FF strings and a bit of tweaking of the design it would have been easy to shoot 190+. Jeez, just talking about it makes me want to make one :)
Just good advice, I have no guess on how much Mark uses haha.
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Surprisingly, all the values were very close together. It sounds like the consensus is around 2 oz give or take depending on circumstance. So I should have enough if I have 3.5 oz.
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Does Elk Sinew really give you 5 times as much sinew than a deer leg. That seems like a huge difference.
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That depends a lot of drawweight and length of the bow ...
Exactly. Depends entirely on the bow. Unfortunately there is no magic formulas
I just got done examining some museum pieces and it seems that the amount of sinew wasn't a preference according to nation or tripe/group.
It was more of a personal choice by the bowyer. Some bows within the same group depending on wood and design, some had nearly 1/3 the thickness was sinew and others only a single layer laid down. I'm sure some bowyers prefer more sinew on their yew than their Osage or plumb. And vice versa.
I've backed somewhere around 25-30 bows with sinew. And I prefer elk leg sinew over most. Moose sinew is really awesome as well but not something I'm allowed to hunt in my state.
And I'll judge the wood to determine the amount of sinew and things such as weight and draw factor in as well. I also don't sinew the entire limb. Especially the tips, not must strain out there no need to waste resources in that part of the bow.
Just dig in man! Start the process and feel out what feels right to you. Just make sure your gluenis good and hold nicely, not to thin. Like a warm syrup consistency. I highly recommend using a comb to lay down the sinew to the limb. Make a nice smooth straight matrix of sinew. You can wrap it up for a nicer smoother drying or leave it open and fill caps as you go, either way a good sinew job is worth the time and the effort. Allow proper drying time and you'll have a very nice bow that'll probably last you a lifetime.
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Greg
wouldn't the amount of sinew depend on how much you are designing the limb to bend?
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I wasn't necessarily looking for an exact number. More of a ballpark. Sure how much sinew you use is going to depend on the length, wood, design, poundage, etc. I just had no idea how much I should be looking at. 1 oz, 5 oz? to an experienced Bowyer who's sinewed a lot of bows they have an idea how much most bows take and can adjust accordingly. I didn't have that hence the post.
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This question gets asked a lot. I always have the same answer.... More than you think. Make sure you have plenty. You don't want to get 3/4 of the way done and run out.
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depend on the length, wood, design, poundage, etc
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sooooo....
what kind of design do you have in the works? ;)
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I have only made 3 sinew bows with 2 shooters 1 faliure do to belly isue self induced belly crack due to over reverse stringing they ranged from 900 grains to 1150 grains of sinew all in the 45-50 lb class & 57 in to 64 in. I weight all my sinew that I put on a bow for future reference, like Bryce said it's a mater of bowyer preference & what's trying to be achieved I find Elk & moose rear leg sinew the easiest to processe not all tendons are equal and you get varying amounts of sinew from each one it hasn't been my exsperience to get 5 times more sinew from Elk leg over White tail leg although you do get more but varies , prepping the back of the bow & glue used is important, this is a endless topic from glue to application a lot of varied opinions & ways to do it , also my bows gained draw weight after a year or so & in the winter months to , there is a fair learning curve with sinew but after your first you will have a good idea of the prsocesse and how to improve the next !
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What's the best ratio of water to dry hide glue if you want to reconstitute it? I was reading that for Knox that you use 1/4 cup for each package (which if a package is around 2 g like I was reading that is, then that makes it 3.3% concentration?) but I also read 35% for dried hide glue which is drastically differant from the 3% of knox. Why would they be so different?
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I don't know. I don't weigh my sinew. I shred what I think I'll need and use it. If I end up needing more then I'll shred more, no biggie.
No need to over think it. Lay a couple layers down and feel it out.
What are your bow dimensions? What are you looking to get out of sinew backing your bow?
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You want to size the back a couple of times with 10% glue then do the sinewing with 30% glue. That is 30% dried glue weight to 70% water weight. Don't go thicker, it is unnecessary.
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Marc St Louis has some old threads & articles in PA magazine about stratigicly laying the sinew on for lighter mass that are well worth the read & there is some good old threads on glue over in the horn bow section also probably no better book written on the sinew process then Adam Korpowitcz composite bow book & Patm has a thread on wrapping in the stickys , depending on the quality of the job you want to do there is a lot of info out there.
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Marc St Louis has some old threads & articles in PA magazine about stratigicly laying the sinew on for lighter mass that are well worth the read & there is some good old threads on glue over in the horn bow section also probably no better book written on the sinew process then Adam Korpowitcz composite bow book & Patm has a thread on wrapping in the stickys , depending on the quality of the job you want to do there is a lot of info out there.
Yeah Mark's is the last quote in the list of quotes I included. It makes sense, but I would love to read up more on it. You don't have any Link's to his strategy other than the quote I already have do you. I've already read over PatM's method but it is due for another visit. Maybe there is more there that I glazed over the first time.
You want to size the back a couple of times with 10% glue then do the sinewing with 30% glue. That is 30% dried glue weight to 70% water weight. Don't go thicker, it is unnecessary.
Mikeswick thanks for that ratio. That's good advice. You or anyone else happen to know why there's such a difference between dried glue and Knox? Or do I have a wrong mixing ratio for Knox (maybe a package isn't 2g like I was reading.)
For Willie, Bryce and others wondering about my bow plan, it is the juniper bow in the Fred Arnold bow trade. I can't remember how long it is right now, I know it's less than 58". I'm aiming for around a 28" draw and 50#. I heard that a good application of sinew should increase the poundage by 10# or so, and since I've only tillered to brace I was thinking maybe I should even out the tiller more, get it bending a couple more inches past brace, and reducing the weight to 45#, or 40#. Does that sound like a good plan?
As far as my sinew plan goes I was thinking of using around 2 oz or a bit more, and doing three layers. One over the whole back and two more concentrating on the crown and working sections. To prepare you clean the sinew and back of the bow with hot water and soap, then size the back with a thin layer, right?
The sinew I'm using actually came from another bow that I wasn't happy with. It had 3.5 oz on it. I went the "don't care about weight or amount just lay where ever I think it needed it" method before, and I ended up putting uneven amounts on each side, which threw off the tiller. I also put on more than I think I needed, and in places that probably could have done with less, like the tips, handle and sides. That's why I want to take a measured approach this time around.
I thinking the sinew from the old bow needs some more processing. I'm thinking of coming it out but am hesitent, because when I try coming out the sinew good in the past I've ended up breaking a lot of strands and creating a bit of waste. Is this normal or is there a secret coming method I don't know?
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Good and the right plan gfugal tillering it a little past brace/then putting equal amounts of sinew on each limb.It should'nt throw your tiller off much at all.2 ounces should get you at least a 10# gain in draw weight.
There's always a bit of waste with sinew.I save it over time to make sinew glue later.
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You or anyone else happen to know why there's such a difference between dried glue and Knox?
have not tried the knox before, but if the glue I use gets too thick, I need to add a little water occasionally, and if too runny, it is not sticky enough
why don't you just waste a box of knox on a trial run with some cotton on a stick or something to dial in your method?
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Thanks for the input guys. I think I might just do a trial batch with the knox and see what the deal is, and report.
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Oh sorry I don't follow that thread. But sinew and juniper is a great combo. My best sinew/juniper was about and 1 1/2" wide. 55" long and held 3" of reflex. Stiff 4" handle and 2 1/4" fades. With flipped tips. Pulled 62#@27" and I think I left 1/16" of sapwood with 3 1/2 courses of good elk leg sinew,Just a really nice piece of wood. I think about it often and wish I never sold it.
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I decided to go with 26 g (400 grains) on each limb so a total of 50 g (800 grains). I put it only on the working limb, about 4 inches from the tip and none on the handle, since I figured it wouldn't do much there and I also had my tillering stick for the reversed reflex. I applied patM smooth sinew method to the best of my ability, other than the intertube part. It's looking pretty good. now I just got to let it dry.
(https://lh3.googleusercontent.com/HNlE059hDU-beyC_UEMW05GPr_KD4ylp0dokw81oG6nrOTfeAlSGqxGnhnSvwff2Cu5IUltKkdV6S4l1pB_ZcR70x3YPGjXDPVv0xiXud3rJI1pcJJP_zULqXcBR3YyGUPJX_XsVIaj9AJiGbRenkvIx4q5Iv807G7dGE55EOsHP-wsMVf__Pn4BR5dyh0g_BAiJ4-Vz87eRPifXrRIovAghr0G7v3LXca9BO8io3omYrCPOB5ztLn8rgUSCPb_j46btKsu7hk2uR1NxUAgvfwVLOC8JhUIzQ7nmAq_j_yX7wm00627Hi3eOcAkQLfiz3rkMJMz4SHCD9JmSnBexreBYe5D-HWLFZ-jlPMWIS_82wbJ_0T4OyekxiD1jNopqWEhoO1mD-3yLwgTgxJ059d6aRVzAaKZH65E29FAkb1eZdjUB0VxrPgvcfX3V7qiJrwSh-4L1Wdfj5PhU0sJptf6xza7M8xjIVOfQj2VnmRMImpcKi5urkiSopP3yMWzThPjwmVpWmh3lMwMF4kAVKyl2zZhSR6qXbNiU-_yFh3eCKX4j1jDP6z2rUYCM9iSIXu62ptUENUZv7YuqXphWU-Apje_iUTYVHNYTw84hq1_NnWmtwWN2dLxkWVHoqXNwgcdHgTER4DST7MBakEw-4Ew4h3DSEbf5YQrB=w1314-h739-no)
(https://lh3.googleusercontent.com/i1BBp9CyxTJQX3uevLwiAR-BlebKFwAIFBYrzoaDZsWc_BkhojoVE4RYTWI6pDnOjhsKycT2Og2U4MGZPlLSK-LoO4RgHdIvJ1gE2m-e7sYIfuimqGY-_DL4z1cdMorBfqyeaP_PwNt5yV6-r2ZGkweCLpic50EC6Vg6YtkxGORSKMxrh6poF96ERNXkqLjFeJp7CGxkD6aG08QqSIsxoVfHsJaKBQxk5f700ufrhb9enRWekK2JAsXES0t_jnUQjprE4_W1IfcWtEcmrXk2RGZYtqIwmJZT_vBbrBeBEiM2Fbb3IfwttUvEwsrEDcYX4RDmlSgyQekf3pMmhwgfKeD589ICktBnEztAt-zlZiuzoR6ouB2nTPGUqg68cgMKh_W7zkBFeznK6qp-RZBm7ZZdR50wc1j7Zq34lHTDAv6dFo5pZ64W1e5Iy6xueZjo5w7YTi6XANYq7KUYwsswaIgkxnBb5-rNJyq4lMH83yXgFXRZJX0PIDU32CUcl3Fz4h48ZCjPsCg3PfSHizPMORTLkYyVEqdmyoCy38QnfrcmWGH-r3yk2NT75_Lo53Lfi3CK7AIciDx2Rd_RpbeHeM_L2Z2oFydsjH4gkFax3UnCUHfDvZDI-EjXjFIIokLr2X-xhwmZpPWzTrjtbKhOkpCUSZHosLkLSdcX=w1314-h739-no)
P.S. I apologize for the mess in the background ::)