Author Topic: Is this crack going to be an issue?  (Read 1614 times)

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Offline Mesophilic

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Is this crack going to be an issue?
« on: February 23, 2020, 05:51:42 pm »
Making a sinew backed osage bow.  Noticed this crack whill rubbing in some tung oil.  Posing one picture without flash and the second with the flash turned on for a slightly different perspective.

This bow has 8 major cracks in it.  The other 7 I was able to fill with superglue and stop them from getting worse.   But being that this one is all oiled up I don't think I'll be able to superglue it.  I'm worried about it spreading to the working portion of the limb.



Trying is the first step to failure
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Offline SLIMBOB

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Re: Is this crack going to be an issue?
« Reply #1 on: February 23, 2020, 06:14:00 pm »
Laminar separation. Generally not good news. With that being in the handle it should be ok. Fill with CA glue. So long as it doesn’t separate in the working limb, I figure your ok.
Liberty, In God We Trust, E Pluribus Unum.  Distinctly American Values.

Offline Mesophilic

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Re: Is this crack going to be an issue?
« Reply #2 on: February 23, 2020, 06:38:54 pm »
Laminar separation. Generally not good news. With that being in the handle it should be ok. Fill with CA glue. So long as it doesn’t separate in the working limb, I figure your ok.

The crack is full of tung oil so I'm not sure the CA glue would stick to anything.  Could I try cleaning it out with acetone and clean it out further by opening it up a little with a razor blade, then apply CA?
Trying is the first step to failure
-Homer Simpson-

Offline SLIMBOB

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Re: Is this crack going to be an issue?
« Reply #3 on: February 23, 2020, 06:46:15 pm »
That’s what I have done. Dig around for any loose matter. Once it’s solid, fill er up. Mine with a similar crack is my wife’s bow. It’s in the working limb and it never spread any farther. Never a problem, but I got lucky I think.
Liberty, In God We Trust, E Pluribus Unum.  Distinctly American Values.

Offline Mesophilic

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Re: Is this crack going to be an issue?
« Reply #4 on: February 23, 2020, 07:07:13 pm »
Thanks guys.  I went ahead and cleaned it out as good as I could with qtips and acetone.  Then gently scraped it a razor blade to clean it out. 

Filled it with the runny CA and then put some of the thicker gelled Gorilla glue over the top.  I find as the glue dries and shrinks this pulls some of that gelled glue down in and fills in the vacancy.

Hope this works, this is my make it or break it moment.  The weather is so dry and I've met so many failures related to wood being too dry that I'm about ready to go over to the dark side.
Trying is the first step to failure
-Homer Simpson-

Offline bradsmith2010

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Re: Is this crack going to be an issue?
« Reply #5 on: February 23, 2020, 09:53:44 pm »
Its gonna hold,,just think positive,,.and get more Osage,,maybe don't store in heated area

Offline Eric Krewson

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Re: Is this crack going to be an issue?
« Reply #6 on: February 24, 2020, 07:02:18 am »
You have a bad piece of wood, wood that side checks will almost always fail.

I made a sinew backed bow out of wood that showed side checks while curing. When I shaped the bow I got past all the side checks in the handle, it looked like a good stave.

I applied the sinew and this is what happened as the sinew cured, the limbs cracked on both limbs just like is in the picture. I even put urac in the cracks and clamped them closed but the curing sinew pulled the cracks back open.




Offline Weylin

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Re: Is this crack going to be an issue?
« Reply #7 on: February 24, 2020, 07:07:07 am »
I agree with Eric, cracks in the side are bad news. There's a chance that it is only superficial, just a remnant of the rough edge before you reduced the stave. If that's the case then it wont hurt anything. If it is truly separating there then I would get started on a new bow. It sucks, we've all been there. Try sticking a needle in there to get a sense of how deep it goes. if it's superficial you wont get in very far at all if you can work a needle in a ways then I wouldn't keep shooting it.

Offline Mesophilic

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Re: Is this crack going to be an issue?
« Reply #8 on: February 24, 2020, 09:39:10 am »
Thanks for the input, guys.  Won't be as disappointing if this bow fails.

High elevation bow making in a low humidity environment has been a trip indeed.  So far all staves of osage and hickory develop checks on me during the bow making process.   I can mitigate this by applying shellac every time I set the stave down for more than 5 mins.  I kid you not, if my wood is above 3% MC then it's quite a surprise.

I've sat down next to a stave, in the shade, to take a break for 10 mins and heard a sharp "tink" sound.  Examine the stave and sure enough,  a 12 inch long crack just appeared on a limb.

Doesn't seem to matter if it's a well seasoned premium stave from Osage Outlaw or something relatively fresh from the auction site. 

Looking at the picture that Eric posted, if I don't have my limbs thinned down enough and apply enough reflex by backward stringing the bow after the hide glue gels, they all split down the side like that to a greater or lesser degree.  There is no maybe,  it happens 100%.  It's taken alot of firewood production to figure this out the hardway, and it's getting more and more difficult to stay persistent in this journey.

Well, it looks like the CA is doing its job for now.  The crack hasn't split any further over night.   It was about 1/32" deep when I probed it last night.  After the oil finish cures I'll rough it up at the fades and do some sinew wraps to see if there's any effect to arrest the spreading.  At this point it's all trial and error to see what works so I might as well shoot it till either catastrophic failure or I'm confident it will hold together.
Trying is the first step to failure
-Homer Simpson-

Offline Deerhunter21

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Re: Is this crack going to be an issue?
« Reply #9 on: February 24, 2020, 10:30:45 am »
add a tight rawhide or sinew handle wrap  :)

i suggest rawhide. itll squeeze the handle to the back
Life before death. Strength before weakness. Journey before destination.

Offline TimBo

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Re: Is this crack going to be an issue?
« Reply #10 on: February 24, 2020, 10:42:59 am »
I need to make a sign for my shop with Brad's words of wisdom:  "just think positive..and get more Osage"  Sort of like "trust in Allah, but tie your camel"!