Osage Sinew Backing ?'s

[DV of WI]

15+ year old osage stave worked down to floor tiller. 64" aprox 42+ lbs. Loaded with linear cracks two run off the sides, one runs full length. I have heated to about 2 reflex.
Should I fill all the cracks before backing with s-glue or TB3 or just leave them and let the hide glue set in them?
When I put the sinew on (I do not have a heat box) how long should I wait before applying the next layer? Considering 3 layers. Doubt that I can get the bow up to 50+ but would like to get as close as possible. The number of cracks make believe could end up as a piece of firewood.

[tishtail]

hi i talked to arrowsmith from wisc. yesterday and he had mentioned that his wife had a simmular thing happened a bow doctor told them too use gorilla super glue for this repair they had nothing to loose tried it he said couldn't believe how well it worked never saw any thing like it before worked well. LjT

[John Scifres]

Personally, I'd not put that much work into a questionable stave.  Sinew would probably save it but it might not.  Plus, a 64" bow is too long for sinew in my opinion.  But, if you want to try it, I'd glue the cracks with superglue.  

I'd use TB3 with the sinew.  Thin it a bit with water and then put a thin layer on the bow's back.  Soak the sinew in warm water, blot it dry and then run it through the thinned glue.  Lay it on.  I let it dry for an hour or so and then run another course.  Three layers sound good to me.  

You should let it dry for a week or so and it should add at least 10 pounds.  I always stop the sinew about 6" from the tips to minimize weight out there.

[DV of WI]

John,

I agree, the only concern I have with that is that the cracks run all the way out to the end and for security I think I'll run the sinew out and over the edge with the first course. I also agree with the time but limited supply of osage right now and lots of time. Need the brake between job hunting on the computer and twisting the brain. It also would give me somethinng to take the frustration out on.

[John Scifres]

I'd probably just glue and wrap the cracks.  But I understand what you are saying.  It's all fun.  Shorten the bow to 60" and you'll have a screamer with sinew.

[DesertFox]

This thread maked me wonder. Could you add sinew to a bow that has already been finished? I have a 61" hickory bow that could maybe stand to gain some speed from a sinew backing...

[TheBronzeAge]

I second that question.  My first bow is not great, but it could probably be halfway decent with a sinew back, and shortening the sinew might correct for the whip-end I gave it.  I assume I'd have to sand off the finish on the back of the bow, and re-wrap my handle post-sinew, but I wouldn't really know.

[Silent Bear]

In my opinion any bow thats over around 52 inches isnt worth the extra time sinewing unless reflexed

[John Scifres]

I would not spend that much effort on a bow that is sub-par.  It's more effective to build another one.  Sinew isn't a bandaid.  It's a design element. Design a bow that uses sinew effectively and it is great. Force it into a design that doesn't optimize, and it is an exercise in frustration.

My best sinewed bows are under 60" and reflexed or recurved or both.

[TheBronzeAge]

Originally posted by John Scifres:
I would not spend that much effort on a bow that is sub-par.  It's more effective to build another one.

This is probably true if you're not a grad student.  As is, I can't afford to buy all that much wood, and so testing a technique on an otherwise cruddy bow is probably worth it for me.  Then I can design a new bow without worrying that I'll lose the money doing something stupid with the technique.

[DesertFox]

Originally posted by Silent Bear:
In my opinion any bow thats over around 52 inches isnt worth the extra time sinewing unless reflexed

In my case, the bow is reflexed. It performs well enough as is though. I think I'll look into some shorter bow designs and try sinew. Thanks for the advice.

[DV of WI]

John,

Whats your draw on a 60"? What's the shock like?
If I were to take a 64" @ 45 lbs and make it say 58" or 60" what kind of increase in weight could I expect? I am trying to get 64# but this being my 4th bow mistakes are still part of the process.Last one is 66" @ 54 lbs. At 64" or 66" I need to widen the limb by 1/16 to an 1/8th or increase the depth a fraction.

[John Scifres]

I draw 27".  Shorter bows have less shock in my experience.  I wouldn't make a sub 60" stiff-handled bow, sinewed or not.  You could expect to gain 3# per inch you cut off, but keep in mind you will have to retiller.  You probably can't make the 45#er a 64#er.