Author Topic: loud pop! bamboo backed bow, cracks on belly  (Read 5920 times)

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Offline lukelawrence171

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loud pop! bamboo backed bow, cracks on belly
« on: August 12, 2014, 01:44:33 pm »
i was pulling back a bamboo backed bow that i finished yesterday and the bow is well tillered it was put together i have made bamboo backed bows before but this was the first time i have ever heard that noise it was right after i had put the string on the bow so the only thing i would think it would be is the string grove setting into place but it has never been that loud and there is no cracks on the bow that are obvious

what could it have been? should i pull it back again? what should i do i have never worked this hard on a bow and i would hate for it to break.   :-[
 
i just went back to the bow and the bamboo is ok it seems to be the osage belly when i bend it backwards
 it makes a weird crackling sound 
« Last Edit: August 12, 2014, 02:04:12 pm by lukelawrence171 »

Offline Del the cat

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Re: loud pop! bamboo backed bow, no cracks ??
« Reply #1 on: August 12, 2014, 01:55:38 pm »
Maybe excess glue or a thick glue line?
My first thought was string settling into the groove same as you. A load of wax round the nock should eliminate that possibility just to be sure that's not it..
Del
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Offline lukelawrence171

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Re: loud pop! bamboo backed bow, no cracks ??
« Reply #2 on: August 12, 2014, 02:02:06 pm »
Maybe excess glue or a thick glue line?
My first thought was string settling into the groove same as you. A load of wax round the nock should eliminate that possibility just to be sure that's not it..
Del
  yea i wish that was what it was i just posted pics  :-[

Offline CustomArcher15

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Re: loud pop! bamboo backed bow, no cracks ??
« Reply #3 on: August 12, 2014, 02:03:55 pm »
Did the overlays delaminate? I had that happen before and it sounds similar to what your saying.

Offline lukelawrence171

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #4 on: August 12, 2014, 02:07:31 pm »
no its the belly does anyone know how to fix it?

Offline Pat B

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #5 on: August 12, 2014, 02:26:29 pm »
I doubt you heard those "cracks" make noise. They are called frets or chrysals and are compression fractures. Apparently the belly is bending more there then anywhere else. There is no real fix for frets. The only thing you could do is reduce the belly thickness and add a belly lam of a compression strong wood.
  Have you checked the boo backing real well. I'd suggest you take a cotton ball and rub it lightly up and down the back. If there is a splinter lifted it will snag the cotton.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Del the cat

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #6 on: August 12, 2014, 02:42:09 pm »
Oh dear...chrysals... horrid things that go much deeper than you'd think (at least 4mm!)
No real cure except rasping 'em out  adding a belly patch lamination.
Maybe the boo was too thick and overpowered the belly.
Del
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Offline Lee Lobbestael

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #7 on: August 12, 2014, 04:05:28 pm »
Wow have never seen that on osage

Offline PEARL DRUMS

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #8 on: August 12, 2014, 04:17:17 pm »
Its your osage grain that bit you.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline CustomArcher15

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #9 on: August 12, 2014, 04:25:38 pm »
I learned a trick that will stiffen enough that it will be safer than it is right now. Take sinew or artificial sinew and just wrap and glue and pray the bow stays together.

Offline PEARL DRUMS

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #10 on: August 12, 2014, 04:35:24 pm »
The osage is failing in compression and basically erupting upon itself. Its the only direction it can go when forced to move. Wrapping it with anything will do nothing. Wraps can work for tension failures where as the backing or back is popping upward.

Are the chrysals on the upper limb just above the handle 10" by chance?
« Last Edit: August 12, 2014, 04:57:19 pm by PEARL DRUMS »
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline mullet

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #11 on: August 12, 2014, 05:06:15 pm »
Bamboo is over powering the Osage. I'd say it's too thick.
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Offline mullet

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #12 on: August 12, 2014, 05:07:27 pm »
Is the belly rounded? Can't tell from the picture and where is it on the limb?
Lakeland, Florida
 If you have to pull the trigger, is it really archery?

Offline JoJoDapyro

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #13 on: August 12, 2014, 06:44:42 pm »
Looks like right at the end of a fade to me.
If you always do what you always did you'll always get what you always got.
27 inch draw, right handed. Bow building and Knapping.

Offline DarkSoul

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Re: loud pop! bamboo backed bow, cracks on belly
« Reply #14 on: August 12, 2014, 07:22:49 pm »
I echo what has been said. Those cracking noises don't come from those chrysals in the belly. Inspect the glue line real closely and use a cotton ball to rub the back.
I don't know what the unbraced bow looks like, but judging from the braced picture, the bow bending mainly near the handle. That would just be bad tiller, and explain the localized chrysals. It's going to be hard to salvage this bow. Your best bet would be to re-tiller it so the midlimbs bend more. That relieves pressure from those chrysals and probably stops them from getting worse. But then you still have to tackle the problem with the cracking noise...which is a different problem in itself.
"Sonuit contento nervus ab arcu."
Ovid, Metamorphoses VI-286