Primitive Archer
Main Discussion Area => Bows => Topic started by: osage outlaw on January 17, 2010, 09:49:00 pm
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I am attempting to build a sinew backed bow for the first time. I have an osage stave that is 60 1/2 inches long. I have layed out the design of the bow on it. I am reading Hunting the Osage Bow, so I am trying to follow some of Dean's advice and make the lower limb shorter. I had to shift it to one side of the stave to avoid a knot. I am hoping to cut it out on the band saw tomorrow. My question is: at what point do I need to apply the sinew? Should I start tillering it first and make sure everything is bending normal? Also, how many legs worth of sinew should I use, and how many layers? And, how long do you let each layer dry? Sorry for the overload of questions.
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This is a question.
You may get many diff answers, so you will have to make up your own mind.
I make my bow, tiller it in at a weight of about 60lbs and shoot if for a few weeks, month, few months, whatever. I shoot the bow in. While this is happening I am in the process of processing sinew.
When I feel that the bow has been shot enough, I cut off the nocks and limbtips to my desired length. If I am going to recurve it, I do that and tiller it again. Then I start sinewing the bow.
The amount of sinew depends on what I am trying to achieve. If it's a 55 to 60 inch longbow then I will apply 2 or 3 layers. If I am making a 55 to 60 inch recurve then I will apply 4 to 5 layers of sinew. If I am making a 45 to 50 inch ponybow then I will apply 5 plus layers of sinew depending on how much recurve I've put in it. I let each layer dry a few days. I stick the bow which is in a portable vise on top of the armoire in the living room so I can look at it every chance I get. I pull it down and inspect and then stick it back up there. On the ponybows, after I think all layers are dried, I stick it in a heat box for a few hours to make sure. Surprising how when I stick it in the heat box it has a little back set, when I pull it out it has alot.
Caution!!!!!!!!!! never ever ever never string your bow when you get it out of the heat box. Let it cool for a few days.
If I apply my sinew then the tillering will not have to be touched after final drying.
That is how I do it.
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I have only sinewed one bow, a short west coast style bow. I got it bending a little, then I started applying sinew. I noticed that the sinew affected the bending quite a bit. So I started to tiller the bow closer to finish, and then I put the final layers of sinew on. And to my surprise it was almost as if I hadnt tillered at all. So I went on tillering until it was where I wanted it.
This is just what I learned through the process, and I dont think you can really go wrong just some do it different than others. I would just say read up on it in a couple different books then make your own gameplan and go with it. You will learn diferent things along the way that will make you want to do it different the next time.
Good luck.
Tell
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I would say,if your bow has the grain to be worthy of a selfbow,then you can tiller it to the safe draw length for the bow length,of a selfbow before adding the sinew.If its not,you better sinew before tillering.No point in straining lesser wood without the protection that keeps it from damageing.Many like to tiller those to brace height before sinew application to allow the limbs to shrink into more reflex,before tillering.
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I do it after I get it to weight and draw length,but before I shoot it much. When it's dry you can go back and tweak the tiller and reduce the weight as needed. :)
Pappy
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I usually sinew after floor tillering or about the time it's ready to brace. I want the limbs bending evenly as possible so that the sinew will pull it into an even reflex. I usually only use sinew on bows that I think are too short or have tension problems. If it'll tiller out and shoot at my draw length without sinew, it probably doesn't need sinew to begin with.
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I've only made a few sinewed bows and they were sinewed after shooting. I think a bow should be at least floor tiller so both limbs are bending together and evenly so the sinew to pull the bow into reflex and by pulling it into reflex before sinewing it I'm assured it will.
I wrote an article for PA Magazine(The Story Of Elkie, vol 15, iss.5 Oct/Nov. 2007) about a bow I built for an elk hunt with Kenneth(Little John). This was the last sinewed bow I built. I have a few more designs I want to build and sinew but that's another issue all together. ;D
I have read many different methods of sinewing bows and they as varied as are the folks that wrote them.
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Thanks everyone. I just roughed out the bow from stave form today. Hopefully I will be ready to sinew in a week or two.
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This certainly deserves more discussion in my view.
I have sinewed longer bows effectively but it has to be done correctly and the bow has to be designed according to the shooters drawlength. Its all about work!
R.
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I agree Roger.
I have handled and shot longer bows that have been sinew backed,which shot welll and it didnt seem to hinder performance in any way.As you stated,the bowyers utilized different approaches than are typically used.
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well i am i nterested in this topic,
as i wil be getting a choke cherry stave soon and plan on adding sinew when the time comes.
but not sure when exactly " the time to sinew" will be
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Sounds good to me guys. I'll start another topic and will throw some ideas around.....
R.
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I've sinewed a few. If I have violated growth rings I will sinew mine when I get to floor tiller, or if I push it, start to get "chicken". If I just want to sinew back a good stave bow for performance enhancement, I'll take it all the way to full shooting, finished tiller. Then sinew back it with hide glue and not TB. Then after a good 2 weeks of drieing, it's hot down here, I'll remove more wood if the weight has picked up too much and retiller.
If you use real hide glue, you will have to continue to remove wood and retiller over the years as it continues to cure and pull the wood in tighter.
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I have sinewed after tillering out the bow and I have sinewed right after roughing out the shape and before I could get ANY bend while floor tillering. My opinion is to sinew as early as you like. Fact of the matter, you are going to be tillering that bow after the sinew has cured and why tiller it twice? No matter how good a job you do the first time, the sinew is going to change everything. As for getting the bow to pull into the correct reflex, you ought see how they pull more and more reflex as you take the wood down off the limbs! The current osage bow I am working on had no reflex whatsoever when the sinew dried (two months curing at room temp), but when I began to take belly wood off, there suddenly came three inches of reflex!
When I lay on the sinew, I take a fully wetted/glue-sodden bundle and lay it on a sheet of glass. I then use a fine tooth comb and lightly comb out the fibers so that they are all parallel and the bundle looks and behaves like a strip of ribbon. You do not need to get the teeth of the comb down into the bundle, but just rake it across the surface gently. Wet your fingers in more glue, pull the ribbon thru your gluey fingers and lay it down on the back of the bow. Get a little overlap on edges and sides of the ribbons, and when this sinewing job dries out there will be the prettiest bow back you ever saw! I rarely get any open cracks or furrows in the backs of my bows since I started using this technique. Oh, and have a large pan of hot, soapy water on hand along with three large dry towels! Messy business at best.
As usual, anything I post is open for arguement and I am willing to listen to anyone that can show me what I am doing wrong.
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I like that idea Jack, I always struggle getting sinew smooth. Steve
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their is a video on you tube, asian style bows, and the ol' boy laid the sinew on the bow and combed it out quite a bit, smoothed it up nice
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JW Halverson. Thanks for sharing that tip on the combing technique. Do you use a plastic or metal comb or does it matter?
I've only sinewed one bow it was an ERC stave. I only took it to lightly floor tillered because I was nervous about the fragile nature of ERC. Unfortunately it blew up shortly after final tillering was complete. I'm ready to start a short sinewed Osage, I plan on getting it to about 3/4 of intended draw length (20"or so) then sinewing. I figure it will be that much closer to final tiller than if I sinewed at floor tiller stage.
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Rick....I use a Dog Flea Comb that I bought from Pet Smart...it's Stainless Steel...and it works good to straighten out the Sinew Fibers once soaked in Glue
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A backstrap sinew question: I have a short, 53" hickory D-bow, width 1 1/8, 47# at 26". I made this from a scrap piece I split off a stave for another bow. It's a straight taper from handle to 1/2" tip. From what little I know, I think I've max-ed out this little piece of wood. I'm thinking of putting 1 layer of sinew on the back for protection, mostly.
If I use backstrap sinew can I just glue whole backstrap piece on the bow ?
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Ya know, Hedgie, I been wondering that myself for some time. I have never heard of it or seen it, but that does not mean it will not work.
I think the problem will be in how some of the sinew is thicker and stronger than other areas, hard to get a consistent tension and it may mess up the tiller really badly. But since you are using your own sinew and stave, and not one of mine, I will "let" you try it out providing you post your results here!
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JW, haha Thanks. I see what your saying about the sinew being thicker/stronger in some areas. Like it tend to be somewhat thinner toward the shoulders than it is nearer the hips. I've never used sinew at all, so it's all new to me. Is it normal practice to really watch the individual strands to alternate thick and thin areas? After all the individual strands would have a thick end and a thin end also? What might be an option would be to split the wider backstrap sinew piece into 4 strips. Then I could easily alternate ends. ? ? ?
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I did that once. I had two long pieces of back sinew and put on on the top half and one on the bottom half. I worked okay but I did not get the results that I wanted. This is why I usually use leg sinew on the back of the bow. I will use back sinew when I wrap the limbs or after I've already put a few layers of leg sinew on the limbs, I will finish up with a layer of back sinew.
I don't comb out my sinew but rather use a plastic pen and run it down over the sinew. It will straighten out the sinew nicely, not as nicely as a comb. I like a more rough look on the back of the bow because I don't cover the sinew with snakeskin.
As far as sealing, 7 coats of clear spraypaint followed by 4 coats of wax. This seals the sinew real good, to the point where I hunt in the rain with my sinew backed bows.
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Jay Massey was famous for hunting sinew backed bows in the rain, but his finish of choice was the 2 part epoxy thinned down with acetone. I imagine he had a pretty good handle on checking moisture content BEFORE laying up the finish!