Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on June 01, 2017, 11:46:34 am
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I want to bend the tip of one limb sideways a bit. I can use steam but it takes a while to cool/ dry. Is it OK to use dry heat? Normally when I use dry heat I confine the heat to the belly but if I'm bending the limb sideways I'll want to heat a different area. Would some heat on the back be OK as long as I don't brown it? It would be about 6" from the tip. It's Yew.
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You think too much, Don :) . Just heat that 4" section of belly ONLY up and move it over. Wait an hour or so and continue on.
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Tryin' to think of a snappy comeback, but I got nuthin' :D Thanks PD
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When making such heat corrections on seasoned, dry wood, I heat it evenly with a heat gun held in my hand and constantly moving... about 3" from the surface, all the way around until it's just about too hot to hold in my hand, then go for it.
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With a wide limb, I'd rather try to bend at the grip where it's narrower.
Del
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I'd already bent it at the handle to get the bulk of it in line. I just needed to get that kink out to get the whole thing right. I actually planned ahead this time. Saved me a couple of bends :D :D
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Actually what I do is heat the edge, applying the heat more towards the belly side than the back. Make sure if you do it this way to heat the outside of the bend so that when you bend it you are compressing the heated side otherwise you could get a stress crack (tension failure).
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Imo, adequate, even heat makes wood more elastic all around and throughout, and so helps negate the effects of both tension and compression when we force it to change shape... and it works better if all of it is permitted to change in any area we bend. If one side shortens, allowing the opposite side to lengthen, by way of sufficient heat,/elasticity means less stress for both sides. Heat/elasticity allows it. Cold/rigidity doesn't. If we don't heat a portion of it, or heat it less, it will try harder to resist our efforts. Don't just heat one side, don't heat one side more than the other, and be patient, keep the gun back and moving, and you won't get checks or frets. Wood is a poor conductor, so give it time to transfer the heat in toward the center as much as possible. Just my 2 cents.
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I'd wait until first brace to see how the string tracks. You may be able to remove wood from one side to line the string up.
If I had to straighten with heat I'd add oil to the belly and sides and heat it until I could bend it and use wedges to move it over.
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Imo, adequate, even heat makes wood more elastic all around and throughout, and so helps negate the effects of both tension and compression when we force it to change shape... and it works better if all of it is permitted to change in any area we bend. If one side shortens, allowing the opposite side to lengthen, by way of sufficient heat,/elasticity means less stress for both sides. Heat/elasticity allows it. Cold/rigidity doesn't. If we don't heat a portion of it, or heat it less, it will try harder to resist our efforts. Don't just heat one side, don't heat one side more than the other, and be patient, keep the gun back and moving, and you won't get checks or frets. Wood is a poor conductor, so give it time to transfer the heat in toward the center as much as possible. Just my 2 cents.
The thing with heating and bending is that changes of shape apparently take place by wood compressing since wood basically doesn't stretch. So if one side shortens, the other doesn't have to stretch.
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Don, with yew I've always had horrible luck making lateral corrections on working limb areas. It always pulls out during tillering. I always try to get a big bend in the handle for string alignment, and maybe in the outer limbs.