Primitive Archer
Main Discussion Area => Bows => Topic started by: ricktrojanowski on February 24, 2009, 09:23:32 pm
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I am about to attempt sinew backing for the first time and I have a couple of questions . I have read many of the previous posts on the subject but still need a little clarification.
1. Is there any advantage in using shorter bundles of sinew vs. longer ones. I am using backstrap and was wondering if I should cut it into shorter lengths.
2. In one of the TBB vol. It suggests putting waterproof tape on the belly of the bow in order to prevent drying checks when the sinew dries. Does anyone think this is necessary?
3. Do I lap the joints of sinew a bit or just butt them together?
Any advice would be greatly appreciated.
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1. HECK NO
2. NO
3. NO, Butt them together. Your second layer will cover the end joints. They might overlap a little in spots just because the little bundles aren't going to have square ends.
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A phenomenon that Jay Massey mentioned in one of his articles was about belly cracks in very dry, old osage when sinewed. I believe it has to do with the moisture that goes into the wood from the sinew and hide glue and as the sinew cures it draws up the back of the bow and the belly expands width wise. I have a bow that is allegedly a Jay Massey bow. This bow is sinew backed osage with halibut skin covering and now has deep checks in the belly. Putting the halibut skin over the sinew before it is completely cured will hold the added moisture until it can escape through the belly. All guesses on my part.
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I overlap the joints a bit to mesh them together
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definitely overlap the bundles.
another suggestion I'd strongly make is to apply several sizing coats of glue before applying the first course of sinew. I feel that the wood will typically soak up the first one or two sizing coats and ever since I started applying three or four coats of glue I've not had any problems with sinew pulling free.
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Thanks for the info, I appreciate the advice.
Sonny- How long do you wait in between sizing coats? Just long enough for the glue to tack up?
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I have had sinew crack staves on the belly, put shakes in the limbs and handles, and literaly tear the growth ring off the back of the bow in places. I did not have this problem before moving to Alaska. I have tried tape on the belly (helps), thin layers of sinew, thick layers of sinew nothing truly solved the problem until I started using titebond III. I have some ideas why sinewing with hide glue is problematic here but is beyond the scope of the origonal question.
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I would degrease the back first, before sizing to remove any oil or debris. Lots of different and successful ways to proceed from there. Good luck and enjoy!
Tracy
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...I'll generally apply a coat or two, let 'em dry overnight then apply another couple of coats.
the back of the bow will be shiny with glue after enough has been applied. at least that's my way of doing it.
hope that helps.
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Thanks Sonny that helps a bunch.