Main Discussion Area > Bows
Deep cook on white wood bows
willie:
what kind of wood is the belly and the backing in the pic in reply3?
you are backing with a lam of untempered wood after heatreating the belly/core?
superdav95:
--- Quote from: willie on September 08, 2023, 02:53:57 pm ---what kind of wood is the belly and the backing in the pic in reply3?
you are backing with a lam of untempered wood after heatreating the belly/core?
--- End quote ---
Willie. They are all shagbark hickory. The pic in reply number three just shows a close up of the dark roasted bow from above. It’s backed with bamboo strip that has also been heat treated on the belly of the strip prior to glue up. The heat treatment of the hickory is all done prior to glue up. Most of the reflex is baked in and not glued in. I think this has something to do with why I get to retain as much reflex as I do.
superdav95:
--- Quote from: Jim Davis on September 08, 2023, 02:01:05 pm ---I can't remember the numbers and I can't find the info--yet--but something like 70?, 90? percent of the tension and compression stresses are withing 10? percent of the surfaces. The middle (neutral) layer has no tension or compression stress at all, only shear.
So what ever heat does to the middle wood has no effect on performance.
Heat certainly is useful in stiffening or bending a limb. But deep heat, not so much.
--- End quote ---
Interesting Jim. I’d be very interested in this info if you can find it. I suspect you are correct regardless on this but would be nice info to have while I’m continuing to experiment for max performance. On a related note my moisture content varies between these bows and the deeper cooked ones typically have less moisture. Not by a huge margin but some. I also find that they absorb less moisture overall if left out in the shop in comparison with other bows that are not as deep a cook. There still may be something to this deep cook stuff yet and some benefits. I’ll keep one playing with it and report my findings anyway. It gives me something to do. :)
Bob Barnes:
Dave, there's some information on page 106 of Bowyer's Bible 1.
willie:
heat tempered wood has been proven to have less moisture uptake than plain dried, so that might be a plus when using hickory.
If the tempered wood were only on the the belly side and a third of the limb thickness, then that would be be sufficient for lam bow as far as having enough heattreated wood to take the compression stress. I mention that as there might be an easier way to heattreat thinner lams to an even consistency.
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