Author Topic: lateral cracks  (Read 3001 times)

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Offline chessieboy

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lateral cracks
« on: December 27, 2007, 01:47:29 pm »
I was trying to put some "flipped tips" on an osage bow.  This was the first time I've tried to do this.  I made a form from a 2X4, heated it with the heat gun and started to bend.  I noticed a cracking sound.  I thought it might have been the from but noticed some later cracks (perpendicular to the grain) at the bend.  The wood seemed to be hot enough to bend easily but the cracks concerned me.  Luckily they were onlyvery shallow and I had left the area extra thick and was able to eliminate them buy scrapping that layer of wood off.  Any thoughts what I'm doing wrong.  The angle was only about 50 degrees give or take.  And the cracks were right where the angle started.

Thanks
Bill

Offline Pat B

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Re: lateral cracks
« Reply #1 on: December 27, 2007, 02:00:55 pm »
Bill, I don't think I've heat bent tips without some cracking. Leaving them a bit thick, like you did, will help because most of the cracks will be eliminated when you reduce the tips to their final size and shape. I like to saturate those cracks with super glue before reducing to the ultimate thickness. I always leave the tips and handle area unshaped until the very end. That way you can make subtle adjustments with the final tiller work.
   When I am heating tips to bend I put the bow in the form with the bow sticking up in the air. When the wood gets hot enough, gravity will start pulling down the bow. I also like to allow the wood to cool over night before removing from the form. If you add the super glue while worm(not hot) it will penetrate down into the far reaches of the cracks.        Pat
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline leapingbare

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Re: lateral cracks
« Reply #2 on: December 27, 2007, 02:19:21 pm »
This is what i do.
 Easy way to steam your wood. Ok get a large pot, and some Aluminum foil, put the pot on the stove to boil and position the bow so it is suspended about 3-4 inches over the pot, than take the aluminum foil and drape it over the bow and around the pot. let boil for 10-15mins take it off and shape it.
  I have gotten lateral cracks doin this too, but when the wood drys out from the steam they close up. Another thing i do is i establish a singal growth ring on the belly of the bow were the bind will take place to insher strength. Well i am no expert but thats how i do it.
 1 pot 5 dolor's , box of reynolds wrap $2.50 , Fixing problems and adding recurvs Priceless.
Mililani Hawaii

Offline tom sawyer

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Re: lateral cracks
« Reply #3 on: December 27, 2007, 05:49:14 pm »
You can strap the outside edge of a bend to prevent/minimize cracking.  Something like a thin piece of metal, even a flexible metal ruler would work.  It helps hold the fibers of the wood together.

I've cracked a few tips too, I just wrapped them with thread and soaked it in glue.  Never had a problem.
Lennie
Hannibal, MO