Author Topic: warped blank  (Read 4744 times)

Offline Ken G

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warped blank
« on: December 20, 2008, 07:24:13 AM »
I have a really highly figured blank that has warped to beat the band.  It was a little on the narrow side to begin with but for a TN it would have been ok but now that it has warped I'm questioning if I can get a 42" gun laid out.  I really don't want to use a shorter barrel unless I have to. 
What's the best way to straighten it and will stay straight after wood is removed and the stock is slimmed down? 
Thanks,
Ken


 
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Offline Eric Krewson

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Re: warped blank
« Reply #1 on: December 20, 2008, 07:45:35 AM »
I straighten a lot of warped wood in my bow making. Dog leg, propeller, roller coaster, I can take them all out with paint stripping heat gun and they don't come back.

I use a 5 gallon bucked full of C clamps and bags of lead shot to pull the wood in the direction I want it to go while I heat it.

It usually takes several sessions to get it just the way i want it.


Offline P.Bigham

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Re: warped blank
« Reply #2 on: December 20, 2008, 02:52:29 PM »
Ken I straightened a Blank once that had a arching curve, I laided It on a beam and used a pipe vise to correct It. I wasnt in a hurry to use It so I would tighten It down some more every couple of weeks. Ended up over correcting the bend by 2or 3 inchs. Let It set that way for about 6 months.Turned out ok.  I have heard of some using Steam to straighten wrists.
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Offline Ken G

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Re: warped blank
« Reply #3 on: December 20, 2008, 05:23:26 PM »
Thanks guys,
Any tendencies for the wood to want to return to that original bow? 
Ken
Failure only comes when you stop trying.

Offline Acer Saccharum

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Re: warped blank
« Reply #4 on: December 20, 2008, 05:25:51 PM »
There was Jerry's/Taylor's method of using hot oil on a finished stock. Never even marred the finish.

You wouldn't want to use oil on an unfinished piece of wood, but it seems to me that heat is the common element here. My friend Karl is a violin bow maker, and they routinely heat the wood to get te curvature the need.

My concern is that you may affect the outer layers of the blank, and when you slab those off, you may have curvature again. Maybe you'd have to do this several times.

Acer
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HistoricalArmsMaker

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Re: warped blank
« Reply #5 on: December 20, 2008, 05:50:31 PM »
Thanks guys,
Any tendencies for the wood to want to return to that original bow? 
Ken
Sometimes yes, sometimes no. On occasion, it will return a little, but usually not all. If I have to straighten one, I usually take mine just a little past required, due to the elasticity of the wood to bounce back. Its the nature of wood to do that. It aint usually gonna be a quick cure. Its like Acer said, you may have to do it more than once. When I used to carpenter, if the sun warped lumber on the job site, I would take the board and flip it over, and lay it in deep morning dew wet grass in the morning time out in full sunshine and let it lay until it pulled back. Its a neat trick and works on 2x material which is only 1-1/2 inches thick, but I have never tried it on a 3 inch piece of maple.
Susie

Offline Robby

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Re: warped blank
« Reply #6 on: December 20, 2008, 05:53:04 PM »
Ken, In the archives, if you search, steaming wood, there is some good information. I deleted the pictures of the steamer I made, if your interested I'll put some new ones up. I have also used Eric's method, for the same purpose, using the same process, in fact, other than the pipe wrench, I use a monkey wrench, it looks like one of mine. Either way will work, but for a thick slab, I think steam will penetrate deeper, so all the wood is being corrected, not just the outer layers. Good luck.
Robby
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Offline Ian Pratt

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Re: warped blank
« Reply #7 on: December 20, 2008, 05:58:27 PM »
Ken, Wayne Dunlap told me this one and it has worked well for me on blanks I am suspicious of - lay it out flat on a concrete floor and check it for movement every week, any appreciable change in a short time and I'd not use it. You have too much time invested and customers have too much $ invested to risk having a rifle that ends up with a reverse cast off , ill fitting inlets etc

Offline Ken G

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Re: warped blank
« Reply #8 on: December 21, 2008, 03:02:38 AM »
Thanks for all the suggestions.  I'll try getting it pulled back and see if it will stay.  If not then 1/2 stock it will be. 
Ken
Failure only comes when you stop trying.

Offline Eric Krewson

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Re: warped blank
« Reply #9 on: December 21, 2008, 07:04:05 PM »
If you use a heat gun the key to success is to keep the heat gun moving and heat your wood slowly so you don't scorch it. When I straighten 2" thick stuff I may take 30-45 minutes to heat the piece. I also use a reflector to get even heating all the way around the wood.

I use a piece of aluminum angle most of the time as a reflector.



Tin foil works well also.