it seems to me that the waist should be fully engaged before bending the bouts. When the bouts are clamped in and the waist is still a bit from the final depth, then you tighten the caul you woild be adding stress to the fibers.
If you have ever tried to bend a copper Pipe you will have experienced the kinking of the pipe, in order that this can be prevented you need a spring that fills the hole and allows the metal to bend without kinking, this is why it is difficult to bend softwood because it has a more open grain, in other words it is more like a bunch of tubes, unlike a hard wood that has a more dense grain. In other words it is like the pipe with a spring in it. I hope this has been of help.
I've had similar crushing with Tasmanian Blackwood sides. The waist caul I have is of the original LMI plans i.e. a stack of ply pieces which can be adjusted to accommodate a wide variety of body shapes. I'm convinced that the crushing at the waist is down to there being too much pressure down through the middle of the stacked waist caul. So I'm going to make a solid waist caul for every body shape and make it longer so that the pressure is spread over a bigger area. A long winded way of saying that maybe your waist caul is the problem!
I have purchased blackwood for my next build, so, I appreciate you sharing this comment. Do you have any other tips for the blackwood. I'm planning on doing a classical guitar from blackwood. I'm considering putting a maple lamination down the centre of the neck.
Very very nice! Thank you for sharing. I appreciate your sharing your test results it is very helpful. Have you thought about trying the super soft with wetting?
A good video. I wonder though. By putting all those timbers in there at the same time ....... wouldn't that have introduced steam to the otherwise dry piece?
Yes, a little moisture would be introduced to the dry piece due to it's proximity to the wet ones but the results still showed that with this particular material the dry pieces did not fair as well as the moist. My theory is that the water is not softening the wood as much as it is transferring the heat to the lignin in the wood more efficiently. Both are contributing but I believe the moisture is more of a vehicle for the heat than it is softening the wood itself.
Those all sound like good options. There is no magic to it. It's just some stainless steel that I got my hands on. I like the stainless because there's less chance of staining. But good spring steel has its benefits too. I just don't like the idea of high carbon stuff and water and wood all in the same location.
it seems to me that the waist should be fully engaged before bending the bouts. When the bouts are clamped in and the waist is still a bit from the final depth, then you tighten the caul you woild be adding stress to the fibers.
Thank you, an informative and quite scientific examination of the bending technique.
If you have ever tried to bend a copper
Pipe you will have experienced the kinking of the pipe, in order that this can be prevented you need a spring that fills the hole and allows the metal to bend without kinking, this is why it is difficult to bend softwood because it has a more open grain, in other words it is more like a bunch of tubes, unlike a hard wood that has a more dense grain. In other words it is like the pipe with a spring in it. I hope this has been of help.
Great Video.you explain everything in great detail. Thanks
I've had similar crushing with Tasmanian Blackwood sides. The waist caul I have is of the original LMI plans i.e. a stack of ply pieces which can be adjusted to accommodate a wide variety of body shapes. I'm convinced that the crushing at the waist is down to there being too much pressure down through the middle of the stacked waist caul. So I'm going to make a solid waist caul for every body shape and make it longer so that the pressure is spread over a bigger area. A long winded way of saying that maybe your waist caul is the problem!
I have purchased blackwood for my next build, so, I appreciate you sharing this comment. Do you have any other tips for the blackwood. I'm planning on doing a classical guitar from blackwood. I'm considering putting a maple lamination down the centre of the neck.
Very very nice! Thank you for sharing. I appreciate your sharing your test results it is very helpful. Have you thought about trying the super soft with wetting?
Great demo......thanks!
A good video. I wonder though. By putting all those timbers in there at the same time ....... wouldn't that have introduced steam to the otherwise dry piece?
Yes, a little moisture would be introduced to the dry piece due to it's proximity to the wet ones but the results still showed that with this particular material the dry pieces did not fair as well as the moist. My theory is that the water is not softening the wood as much as it is transferring the heat to the lignin in the wood more efficiently. Both are contributing but I believe the moisture is more of a vehicle for the heat than it is softening the wood itself.
@@gregnelson7168 Thank you for the explanation
What do you use for steel ? 1075 or 1090 ? Thickness ? 0.008 0.025 ?
Those all sound like good options. There is no magic to it. It's just some stainless steel that I got my hands on. I like the stainless because there's less chance of staining. But good spring steel has its benefits too. I just don't like the idea of high carbon stuff and water and wood all in the same location.
thank you.