Primitive Archer
Main Discussion Area => Bows => Topic started by: Newbreedarcher on January 16, 2015, 10:12:54 am
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Hello all, as the description reads I am going to try my hand at sinew backing a hickory bow. I have made several hickory self bows in the past two years to a good degree of success. I have made 8 bows and 5 are still alive and doing great. Maybe I am still too novice to attempt sinew backing, however, I cam across a basically endless supply of beef tendon for free and have about 50 10-14" pieces ready to be processed. so, that being said, I have a bow roughed out at 68" 1.5" limbs that fade to 3/8" starting 12" in from the ends. I was really wanting to make a molle but I'm not sure if I've done myself in with the with of the working portion of the limb. It will be drawn to 29.5". Is 18.75" working limb enough if it is sinew backed? My self bows have been around 2" and that worked great for me. Although I may have been over building them. Sorry if this is a noon question guys. Thanks in advance.
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Newbreed, First, a 68" bow is too long to get the benefits from the sinew unless your draw is 34" long or longer. Also, hickory isn't the best choice for sinew backing unless you live in a very dry environment.
A few years back I copied Jay Massey's Medicine Bow, 60" sinew backed hickory pulling 55#@26". Depending on the humidity it's draw weight will fluctuate between 45# and 65#@26".
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Thank you pat! I was curious about the length as well. I guess I will just see if this stave works without a backing. Yeah I do live in a very humid area, southwestern ny, summer months it is regularly 90 percent or more. I do notice the draw weight and string follow fluctuations in the summer as well. I guess I was hoping beyond a hope :P I do have 2 Osage staves coming to me. Would that be a better choice for sinew? and could I get away with a shorter now with Osage? Sorry for the noob question again. Never worked with Osage. It's not available locally so never really looked into layout with it. Thanks again.
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I don't quite agree with pat. I agree with if its assumed to be a normal flatbow. But your not making a normal flat bow,and making a Molly instead,and already have it cut out. I'd say its doable if you made the handle section longer than normal and only placed the sinew over the working limbs,and when ya go to sinew it reverse brace it 4-6" then lay the sinew down..again just over the working limbs since your making a molly. You could chop off a couple inches and make the handle normal length as well. That would work well for a 29.5" draw a d work the sinew like it should. BUT...it needs to be stored in a dry low humidity place when not in use.
Since you already cut it out....I think you dont have enough width and surface area of working limb for a selfbow of those stats. Not any hunting weights at least IMO. Unless ya made the handle to bend perhaps instead of being a stiff handled one.
I'm just playing devils advocate as there is a viable option other than pats response... And I think it's silly to sinew hickory unless one lives in a desert, or intends to use it there.
Lots more to say or vary from what i said,but that's as short as I can make it.
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You are the bad Chris! ;D ;) Newbreed, listen to Blackhawk. He does know his stuff.
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Thank you both for the advice! One more question. Can I use tb3 to glue the sinew? I was gonna use Knox gelatin but if I can help the sinew stay dry with tb3 I will use it. I also planned on putting snake skin or rawhide on to help. I heard that can help seal the moisture out of the sinew. Thanks again!
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Id suggest using knox if you want the sinew to really do what its capable of.
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Well there you go
you heard from the wise old bird and the bad and good Chris
you have a wealth of knowledge before you and there for I say go for it show us all what you can do now
Guy
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New breed,
As a disclaimer, this is from reading--NOT experience. Most of what I have read says that the Titebond glues will not aklow sinew to stretch, making it no better than rawhide for adding tension and therefore weight to a bow--so it will "just" serve to protect the back.
Again, I have not yet backed a bow.
Russ
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Your not far off Russ.
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Tip the levers back a bit, lightly toast the belly of the working limb into reflex and then sinew in reflex with the sinew ending at the base of the levers.
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So, I was talking to my uncle, as he came by my place to borrow my table saw and he asked how what i was up to. long story short, he told me he uses fish maw glue for his furniture work. I had never heard of it so I looked it up. Do you guys think that would be better than Knox?
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Fish air bladder glue is used in some of the Asiatic horn bows and is very strong. I would go with your first thoughts, see how that works for you and experiment after you have some experience.
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The fish based glue should have a longer open time which can be advantageous to a first time "sinewer".
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You know, PD, I talked to one guy who supplies various glues, rawhide and sinew--who disagreed on whether sinew without hide glue would tension the back. Don't want to name him, but he was the one voice I have heard in opposition. At the time, I was only interested in TB 3 with rawhide, and the part about sinew was kind of an aside.
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Comancheria,
I think i know who that guy is.If its who i think it is,he learned how to do it from another guy i know.
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Thank you all very much for your advice. I have much to consider at this point as I don't have a lot of time to enjoy the craft these days. My wife and I just had our first child and a two week old doesn't care if I really want to floor tiller my latest stave! I will post pictures as soon as I can. Again, thank you all very much!
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The 68" hickory stave should make you a very nice selfbow as it stands.
You won't get the full potential from the sinew with TB glues. It will make a good, strong backing but only add a little performance if any.
Being made from the same protein the sinew/hide glue forms a matrix with both substances combining making it one and shrinking and stretching in unison to preform it's magic.
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So my uncle gave me dried carp pike and musky swim bladders. Can I do like a 50/50 mix with the Knox? To get more time to work with it but still have quicker drying time than all bladder glue?
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honestly if your not in a dry climate sinew on hickory is a bad choice..1 good reason..hickory is very hygroscopic..it absorbs moisture..so drying a hickory to below 12 % to preferably 9 has to be done indoors...or it will never get below 12... with sinew being wet when applied and hickory being so light when dry, I found it to hinder performance rather increase it....now if you were in Arizona Id say go for it... why back it unless its a board... hickory is a beast on tension and compression....gut