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Steaming yew

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JW_Halverson:
I have a yew stave, 1.5 inches by 1.5 inches by 74" long. It has 3 inches of decurve at the worst part, one limb having a long, gradual decurve, and the other limb having most of the decurve in the last 15 inches.

I am thinking of building a steam box and steaming the whole thing all at once and pressing it into a form to bring the whole thing straight in one go. To create the jig, I am thinking of creating a jig that allows for "springback" by taking the wood 10% past straight. If I take the wood down to front profile and taper thickness close to where I will start shaping/tillering, it should not need to steam for an excessive length of time.

I have traced the side view profile on a long sheet of paper and have measured every 3 inches and then drawn the new shape with the extra 10% figured in at every 3 inch interval.

Does this make sense? Kick holes in my theory, point out flaws if you can see them.

Pat B:
John, I prefer to do one limb at a time, clamped at the handle and out the limb.

bownarra:
Same as Pat here. One limb at a time. I would just heat treat it
Also do not rough in the tapers. Make it the same width and thickness along the length.
You could probably achieve the same thing by gving it a good heat treat. Make sure it is dry, dry, dry if you go this route tho!

Del the cat:
I'd go with whatever is most manageable and convenient*. Bear in mind it often take more than one steaming to get it right. I'm in favour of rough it down in thisckness but leaving plenty of width. The less thicknes, the quicker it gets up to temoerature and the less stress wehn bending.
* E.g The available size of steam chest, form, number of clamps, potential speed of clamping phase of moon etc.
Del

superdav95:
I agree with del and bownarra here.  One step at a time.  You’ll lose a lot of heat quickly out of the steam box or bag before getting to your clamping jig set up.  You’ll be hard pressed for time to get it all done in one go in my opinion.  I’ve never tried it like this in one go like you say with steam myself but can just imagine the rush to get it all done.  With the heat treating smaller sections like what’s been already said you’ll have the time and can be more precise and still perform your slight over corrections as you want by measured degrees.  I’ve used a similar method told to me by bowed and it has helped me a ton with twisty and badly bent wood.  Just a word of caution. Yew only likes to be heated up one  time in the same spot for corrections. I’ve gotten away with a second treatment correction but watch your heat and just work your way out from the handle.  Also I’ve had luck with minor corrections at the handle with trying to align the string in the middle of handle too with clamping bow sideways.  I’ve seen whelyn do this and I’ve since done it this way with good luck.  Best of luck.  Lots of good suggestions here.   

Cheers 

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