Author Topic: Advice required lifting sinew back.  (Read 2427 times)

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Offline spinney

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Advice required lifting sinew back.
« on: January 14, 2010, 12:29:41 pm »
Hi Guys,
I have a 64" Osage static recurve pulling 50Lbs @ 28" sinew backed with diamond rattlers on the back.
I recently had a flood were I live and put this bow some where warm and dry whilst I delt with the flood.
Anyway all dry now.
So I took the bow from its case last night and examined it all looked good.
I began to string the bow using a stringer and there was a terrible CRACK before I got the string on.
Upon examination a 2  inch section of the sinew backing has come away from the bow on the bottom limb just at the fade.
This section has not come away across the whole back of the bow  but about 1/2 inch from the edge.

I built this bow two years ago and dearly love it!

But how to go about a repair?

Well I have two schools of thought.

1) Reglue with hide glue.
The problem with this being the snake skins on the back which may not allow the glue to dry.
I thought a way around this may be to make small holes using a needle in the snake skin to allow the water to escape.

2) Reglue with crazy glue.
would this work at all?

What would you do?
Any advice at all would be very welcome.

Andrew

Offline Badger

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Re: Advice required lifting sinew back.
« Reply #1 on: January 14, 2010, 02:06:56 pm »
     One time a sinewed an osage bow and the entire sinew back came off. I hadn't sanded the surface well enough, not sure if this is your problem or not but I would see if the sinew will pull off in one piece if it does sand the surface and glue it back down. Steve

Offline artcher1

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Re: Advice required lifting sinew back.
« Reply #2 on: January 14, 2010, 02:26:13 pm »
I would think that any moisture trapped would be absorbed through the wood and old glue and set just fine in time. So I wouldn't worry about trapping moisture. Hide glue will work, so will the tite-bond glue. I've used super glue for small sections of edge repair but nothing to the extend that you're talking about. Another option is using thin, runny two-ton epoxy thinned by warming it up. Warm up the section of the bow to be glued as well if you go that route. Clean-up could be a problem if you already have a finish on your bow so take that into account if you use the epoxy. I use lacquer thinner to clean/thin the two-ton epoxy that I use.

What ever method you choose, just make sure to work the glue/epoxy under the sinew thoroughly. Good luck. ART

Offline Pat B

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Re: Advice required lifting sinew back.
« Reply #3 on: January 14, 2010, 02:44:02 pm »
I have done a repair like this with TBIII glue. It held up fine after that. Also you might be able to slightly re-heat that area to gel the hide glue, wrap it and let it cure for a few days.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline spinney

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Re: Advice required lifting sinew back.
« Reply #4 on: January 14, 2010, 03:32:34 pm »
Thanks for the suggestions so far guys please keep them coming...

Pat what you say about heating the bow and re-gelling the glue may have been what caused the problem in the first place.
After the flood the bow was stored very close to a radiator in order to keep it dry.
When I attempted to string the weapon it was quite warm to touch, this may have caused the glue failure.
This bow was/is a real work horse shot 1000's arrows through it over 2 years, not the fastest bow in the world but a real pleasure to shoot.

Andrew
« Last Edit: January 14, 2010, 05:37:51 pm by spinney »

Offline spinney

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Re: Advice required lifting sinew back.
« Reply #5 on: January 14, 2010, 05:36:11 pm »
Actually guys just had another idea of what may have caused this to happen.

The stringer used to string is bow sits just were the recurves begin and the flat part of the bow ends.
Each recurve is 6 inches this means the length of the bow as far as the stringer is concerned is just 54 inches.
The stringer is very long. Doesn't Even start to tension the bow until it reaches my knees, and can slip the string on at waist height.

You guys know whats going to happen if you put a FINISHED 54" bow on a tiller tree with a VERY LONG string...


.... The tiller will look awful with the bow appearing to hinge straight out of the fades.

Could this have contributed to the failure?
should I shorten the stringer?

Andrew

Offline artcher1

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Re: Advice required lifting sinew back.
« Reply #6 on: January 14, 2010, 05:55:35 pm »
I doubt if that "long string effect" would cause you sinew to pop loose. Probably just a bad bond for whatever reason. When first using the long tillering string you don't yet have the mid to outer limbs bending as with a finished bow. So more of the stress is more evenly placed and not concentrated in one single area once finished.

You can go to a shorter stringer providing you can get your regular string on easy enough. But it's easier to string recurves with the longer stringer, especially those bows with a lot of curve. ART

Offline wodpow

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Re: Advice required lifting sinew back.
« Reply #7 on: January 16, 2010, 11:21:04 pm »
Can you see under the sinew that pulled loose is it yellow from Osage oils? Normally hide glue don't let go without pulling a little wood loose but if the glue didn't get a good hold it will pop loose clean.   Being you have snake skins over the sinew you will want to be careful.  If there is not a lot of yellow on the glued sinew  and it is clearly got hold of the wood like is the glue ripped where it pulling loose you could apply some mild heat like 150 degrees and and add some more warm hide glue wrap it tight with say some big cut rubber bands and let it stay warm and get into the wood.  If there was lots of yellow one the glued side then the heat made the oil in the wood come out and float the glue free you might need to wash the area with acetone a couple time till a rag with acetone soaked rubed    on it don't pick up that yellow color  and use the warm wood warm glue and wrap it tight with rubber bands.

Offline FVR

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Re: Advice required lifting sinew back.
« Reply #8 on: January 17, 2010, 03:06:03 pm »
I've repaired bows that had this problem.

Small lifts, I usually use superglue, make sure areas is dry, superglue then wrap the area with sinew.  On larger areas I have just pulled out the hide glue and re-glued the area that came undone. I usually make a real mess, then again I wrap with sinew over the area and up and down about a half inch.

Many have said that I did not need the sinew wrap, probably did not because the sinew was not damaged, but I do it just to make me feel nice and comfy.

When I wrapped the one limb that needed repair, I would then wrap the other limb just to make them match.

Good luck.

Frank
Can't cheat the mountain, pilgrim.
Mountain got it....

Offline wodpow

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Re: Advice required lifting sinew back.
« Reply #9 on: January 18, 2010, 12:24:57 am »
FVR me to wraps at the fades and the limb ends and wrap it down tight so its nice and smooth if I put skins on over  it    . Spinney  some times you will get that when the heat makes the sinew draw and sometimes pulls loose, some fresh hide glue and a wrap should hold it sounds like it shrank and pulled loose not pulled loose from being over stressed right. if so you should have a easy fix.

Offline spinney

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Re: Advice required lifting sinew back.
« Reply #10 on: January 18, 2010, 04:56:13 pm »

Thanks guys for your replies


OK guys I went down the hide glue route.
I warmed the bow using a heat gun carefully. Mixed up the glue. De greased the whole area with acetone.
Filled the gap under the sinew with hide glue. Warmed the bow up again. Then wrapped the area tightly with a bandage.
I plan to leave it at least a week to dry maybe two or three.
I haven't wrapped[ed the area with sinew but will do if this repair is not successful

What do you all think?