Primitive Archer
Main Discussion Area => Bows => Topic started by: Marlin on June 18, 2011, 02:45:21 pm
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Is there anything else out there like sinew that can be glued to the back of a bow. Something that will hold a reflex and help the bows performance.
I know other woods or bamboo can do this, but what about fibers. Or is sinew it. Marlin
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raw flax there is a good bit of info in one of the bowyers bibles on flax it works very will like sinew when it is raw and combed.
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I don't know of anything that will mimic sinew, sinew is elastic, while flax is stiff but not elastic.
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was not saying it is same but it is the only thing I can think of that makes a good backing that is applied like sinew. all I know is what I read about it and that basically said that it is dang close to as tough as a backing as sinew. it is what linen is made from which is widely used as a backing from what I can tell. But the other fella might know more than me from experience I would listend to him.
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First, whether or not sinew actually helps performance depends on how it is used, what sort of bow it is glued on and what measures you're using to judge performance. Sinew is heavier per unit strength than wood, so if you put a sinew backing on a longer bow you are probably hurting performance more than helping, by any measure except durability. What sinew is good for is drawing a shorter bow into reflex and keeping it there, although even with shorter bows I suspect you're hurting cast.
Rawhide does not pull a bow into reflex quite like sinew does, but it can a little if you apply it right. Flax and other vegetable fibers are strong, but don't pull a bow into reflex and can actually overpower the belly wood of some species (as can sinew, for that matter), so vegetable fibers can be risky.
If you want the characteristics of sinew (pulls bow into reflex as it dries, diminishes performance of a bow relative to one of that same side-view profile made without sinew), there really is no substitute. At least none that I've found.
To be honest though, I think sinew backing is highly over-rated. I haven't done it myself in a few years, and am not planning any sinew-backed bows for the foreseeable future. If you choose a good piece of wood, let the wood thoroughly season, and design a bow for its intended use and for the type of wood you're using, sinew backing isn't necessary. I routinely make short bows, even bows under 40 inches long, without backing them with anything and they turn out fine and are quite durable.
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Well said. I couldn't agree more. I've only sinew backed a couple of bows, and it is terribly tedious and time consuming, and doesn't always work. I think the Plains Indians used sinew for short bows they used from horseback, made from marginal wood. It allows a longer draw from a shorter bow, and if applied properly, increases performance.
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Thank you all for the input. I am intrigued by the Hungarian and Korean horn bow and that is why I am asking about sinew. I was watching a Korean bow maker on You tube. He had this what I think it was sinew but it almost looked to long to be sinew. Could it have benn flax? I really don't know. It would be a monster elk or deer. Thanks again, Marlin
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Sinew is pretty much it, like everybody else said. The sinew you saw could come from a lot of different animals, maybe horse?
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Silk applied while stretched will apparently hold a reflexi n a bow. The opinion of some is that silk is too stretchy and keeps stretching but it is trapped within a less stretchy glue matrix. Spitfire horsebows are backed with silk.
You can find old articles (Poular Mechanics?) detailing the use of silk backing strips.
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Sinew is the only materal that when aplyed will draw reflex into a bow. More with each later. Anything else the bow has to be reflexed and the backing glued onto it to hold the reflex. I use streer sinew the most (when I use to back bows) because of the leanth. I've used all kinds deer,buffalo,cow,horse, antalop some AFRICAN, even had some that was surpose to be (BOA) snake. I'd got from someone along time ago. I could'nt see or find any difference in any of it. Except lenth. I NEVER FOUND or know of anything that minic's sinew in anyway.
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I didn't watch the video, but back sinew from deer can be quite long. I've gotten whitetail deer tendons that push 30 inches, if cut well from the animal. Elk is longer still, horse even longer, and bison the longest of the North American mammals I've had experience with. Cow back tendons can be quite long, rivaling those from elk and horse, but I've always found them to be greasy and avoid them.
Leg tendons from grazing animals are actually quite long also, although most folks who gather then from butchers get short pieces because butchers often saw the legs off at the ankles or slightly above, leaving only a small section of the tendon intact.
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Combed flax when used in small bundles has superior strength to just about anything else, even the wood that it's applied to. But it will tend to stack on you when the bow is drawn because it becomes progressively harder to stretch, which Will in effect increase your poundage.
Info taken from the Bowyers Bible Vol. 1 pages 107-109
The bowyers bible talks about it to some extent and their testing showed that a 1/10th diameter flax sample pulled 37lb. @ 1% stretch, 98lb. @ 2% stretch and 182lb. @ 3% stretch which was the breaking point for the sample. By comparison a sample of sinew didn't start stacking until it had stretched 10%
So you can see how it stretches much differently than sinew and it will increase the draw wt. of a bow all the same, just in a different way than sinew will.
I think flax comb is very underated and doesn't get the recognition it deserves as a superior bow backing, it just depends on what your looking for. If sinew which has a lazy stretch compared to flax because sinew stretches more, and sinew will hold the recurve in a bow, then based on the results from the BBI why wouldn't flax also hold the recurve in a bow?? The answer is that it will, but it may not have the "Feel" to it your looking for from sinew, nor will it be as smooth drawing as a sinew backed bow.
Hope that helps.
I have some flax comb for trade if you want to try some, just shoot me a pm.
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Patm, I had no idea about the silk. I have read that it stretches alot before braking. This is news to be though. Sinew is more stretchy than rubber, and has a higher resiliency too, so it pops right back after being stretched, I think this is the factor that makes sinew bows so snappy? Is that right? Silk would have to have a high resiliency as well if it could hold bows into reflex.
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I have some flax comb for trade if you want to try some, just shoot me a pm.
PM sent, Thanks, Marlin
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Got it Marlin, right back at ya!
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http://books.google.com/books?id=oScDAAAAMBAJ&pg=PA140&source=gbs_toc_r&cad=2#v=onepage&q&f=false