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Thermally Modified Dread
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Author:  Grant Goltz [ Thu Dec 10, 2015 11:14 pm ]
Post subject:  Thermally Modified Dread
After stringing up the OM made from thermally wood, I had said that a Dread was next in line. I am ready to begin and have picked out the main wood.

This time I will use one of my high quality white spruce thermally modified tops
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This one has uniform straight grain and no stains

Pretty much a very uniform 17 grain lines average/inch all across
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And perfect 90 degree vertical grain all across
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This is about as good as eastern spruce gets :D

Back and sides will be thermally modified Cambodian Beng. Here is the modified back and the un-modified sides
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A bit of shellac to show the color. The sides will be thermally modified after bending

This wood is very similar in properties to BRW, but has an orange color. The thermal modification gives it a more pleasing brown color. The plan is to have everything except linings, bindings, and peghead modified. Again, I will use the spring tempered Phosphor bronze bar frets.

This will be a more leisurely build, but I will give periodic updates.

Grant
Author:  bcombs510 [ Thu Dec 10, 2015 11:22 pm ]
Post subject:  Re: Thermally Modified Dread
Grant, would thermally modifying the sides before bending make them brittle or hard to bend? Or are they modified after bending for a different reason?
Author:  Grant Goltz [ Thu Dec 10, 2015 11:37 pm ]
Post subject:  Re: Thermally Modified Dread
bcombs510 wrote:
Grant, would thermally modifying the sides before bending make them brittle or hard to bend? Or are they modified after bending for a different reason?

Yes. So far, I have not been able to do a decent bend on thermally modified wood. It gets very stiff and likes to break. The process I have used on about 5 sets of sides has worked well. When I get to that point, I will post the process.

Grant
Author:  SteveSmith [ Fri Dec 11, 2015 10:13 am ]
Post subject:  Thermally Modified Dread
I tried to bend thermally modified curly red maple and could not get it to bend. The same wood, unmodified, bent like butter. And yes, I tried every method I could come up with; combinations of wet, dry, high heat, steam, and lots of SS2. Nothing worked well enough to do anything more than very shallow bends.
Author:  Grant Goltz [ Fri Dec 11, 2015 11:59 am ]
Post subject:  Re: Thermally Modified Dread
SteveSmith wrote:
I tried to bend thermally modified curly red maple and could not get it to bend. The same wood, unmodified, bent like butter. And yes, I tried every method I could come up with; combinations of wet, dry, high heat, steam, and lots of SS2. Nothing worked well enough to do anything more than very shallow bends.

That seems to be one of the properties of thermally modified (or torrefied) wood....it seems to take a set in whatever shape it is in when treated. In some ways, that is a positive thing...the wood does not warp, twist or do any other ugly movements, but it does require a few changes in process. I tried bending without treatment and then doing a "pseudo-treatment" in the oven, mainly to get a color match. And it seems to work well, but there are a few caveats. If the bend is not pretty much right on when you bake it, it can be difficult to coax it into the right shape, so no springback is allowable. But the upside is that you can ramp the temp in the bender up to around 375 for however long it takes to really set the bend without being concerned about the wood darkening.

I have no idea how the builder(s) claiming "fully torrefied" guitars deal with their sides. I do know that at least one of them buys their wood through a broker who has it treated at the same facility that I do, so they are using the identical thing that I am. I know that because John has run all of the guitar wood he has treated at the same computer controlled cycle, often in the same batch as mine.

So while there are claims, marketing hype, and all that, there are still a lot of cards being played "close to the vest" ;)

But we ARE learning a few things :D

Grant
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