Author Topic: 52 inch sinew backed osage. sinew came off??????  (Read 3838 times)

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Offline jturner

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52 inch sinew backed osage. sinew came off??????
« on: November 09, 2009, 12:51:40 pm »
I made an osage self bow 52 inches tip to tip bout 55 lb @ 28 It had extremly tight rings so gary  davis told me because of the rings and the short length it may be a good idea to back it with sinew and flip the tips. It was too late for the tips but i did the sinew and after bout 100 shots the sinew was lifting, ended up coming off in full sheets. my question i guess is do i have to score the back or was the glue mixed wrong to make it come off like that?
Jake Turner     Michigan

Offline Pappy

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #1 on: November 09, 2009, 12:56:10 pm »
I rough the back a little and also rub it down with acetone just before I start to glue it down. :)
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Offline Keenan

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #2 on: November 09, 2009, 12:56:34 pm »
Did you degrease the wood real good and size the back of the bow with glue? What kind of glue?

Offline jturner

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #3 on: November 09, 2009, 01:06:26 pm »
I sanded the back with 60 grit and sized it. i used knox. now i am back to a self bow and i have 2 sinew backing strips.lol can i reuse them or just throw them out? no i didnt degrese it. was thinkin bout gluein the strips in a kids bow as a backing for added security
Jake Turner     Michigan

Offline Justin Snyder

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #4 on: November 09, 2009, 02:16:15 pm »
I don't worry about roughing up, but I sure do degrease. You should be able to soak the sinew and use it again. Justin
Everything happens for a reason, sometimes the reason is you made a bad decision.


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Offline kylerprochaska

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #5 on: November 09, 2009, 02:51:30 pm »
How long did you let the sinew dry or cure?  I know I just put down acouple layers on my 56" recurve about a month ago and I was instructed not to stress the bow for at least 3-4 months...Im going to put one more layer on and then let it cure until April or so before I touch it again...

-Ky
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coyote pup

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #6 on: November 09, 2009, 02:57:02 pm »
One other thing - Knox can be questionable. I have had boxes of Knox that I made glue with the same day I bought them and they made very hard, strong glue. - BUT -  I've also had boxes that I made glue with the same day I bought them and they didn't make glue worth crap. The glue was all weak and soft. Not every box of Knox will make a good glue.

I can't say of course if this was your problem or not. All I can say is that if I sinewed a bow with a bad box of Knox, it would most definately come off.

Just my 2 cents.   

Offline ricktrojanowski

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #7 on: November 09, 2009, 08:56:29 pm »
I've only sinewed one bow so far, and it's still drying, but I degreased it many times with acetone, and put on two coats of hide glue to sinew.  It was ERC. and when it was drying it actually pulled about 3" of the top growth ring free of the rest of the bow.  It might have been not degreasing the bow that caused the problem.  Osage is pretty oily stuff.
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Offline wodpow

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #8 on: November 09, 2009, 09:52:57 pm »
Thin growth rings  mean little growth at that part of the log so the oils got concentrated in the thin rings had it  happen twice on one Osage recurved bow the sinew was lemon yellow were it had made contact with the wood acetone didn't help the rag I was wiping it down with never stopped turning yellow. Finally I made a hard wood ash paste scored the back good  and put it on thick let it dry for a couple of weeks then did  a high pressure wash and let it dry the wood was not near as yellow as before and when I sized it with glue and let it dry in a warm place for a week then went to flexing the limb to see if the glue was going to pull loose along the side and flake off it didn't so I applied the same sinew after a long soaking in some warm water to get it loose, I used the hide glue violin makers use.  If  you see the glue pulling loose along the edges stop and degrease with lye or wood ash paste I can't find lye anymore so I used wood ash mixed with a little water to make a paste.

rockhound34

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #9 on: November 09, 2009, 09:55:58 pm »
I sinewed a bow once ,didnt wait for the glue to cure, an it came off. I call that lessons of getting in a hurry.A big no no I have better results in taking my time. I was in disbelief when it happen.Ha

Offline wodpow

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Re: 52 inch sinew backed osage. sinew came off??????
« Reply #10 on: November 09, 2009, 11:34:22 pm »
When it pulled loose it came off in whole sections. Next time it held in spots, last time it held tight the whole bow if you got that yellow on your sinew where it pulls   loose no amount of time is going to make it stick to the bow it will have to be deoiled and roughed for the best hold. I bet there was no glue at all on the back kind of like some releasing agent was used right. degrease it and it will hold tight