Wood Sterilization

I know that 133 degrees is the magic # for wood sterilization. But I think I read on one of the forums that 120 would work if left at that temp for a longer period. Does anyone know if that is legit? I also read to get the internal temp of the wood hot enough you have to go past the desired temp. Whats the scoop on that? Its been a long time (years) since I ran my kiln.

While where at it. Anyone have a guesstimate on how long it will take to bring 10/4" maple and walnut slabs that go in at 20% down to below 10%?

James

Everything I remember reading indicated 130+ was needed. I think Gene Wengert indicated the kiln needed to be 160 F for several hours to reach 133 in the center of a 4/4 board. You can search the Wood Web for details.

ALso, the USDA Forest Service has a publication on heating to sterilize. I didn't read it entirely but perhaps it addresses your questions about the temp and time needed.
https://www.fs.usda.gov/treesearch/pubs/37413

JKJ

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Originally Posted by James White

I know that 133 degrees is the magic # for wood sterilization. But I think I read on one of the forums that 120 would work if left at that temp for a longer period. Does anyone know if that is legit? I also read to get the internal temp of the wood hot enough you have to go past the desired temp. Whats the scoop on that? Its been a long time (years) since I ran my kiln.

While where at it. Anyone have a guesstimate on how long it will take to bring 10/4" maple and walnut slabs that go in at 20% down to below 10%?

James

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Quote:

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Originally Posted by John K Jordan

Everything I remember reading indicated 130+ was needed. I think Gene Wengert indicated the kiln needed to be 160 F for several hours to reach 133 in the center of a 4/4 board. You can search the Wood Web for details.

ALso, the USDA Forest Service has a publication on heating to sterilize. I didn't read it entirely but perhaps it addresses your questions about the temp and time needed.
https://www.fs.usda.gov/treesearch/pubs/37413

JKJ

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Hi John,
Thank you for your reply. Most of what i know about drying came from Gene. He is a wonderful member of the woodworking community. That said his solutions are geared toward industry and not the home hobbyist. I wish I could remember what I has read! I'm starting to think it had to do with 160 temp for a short period vs a lower temp for 24hrs.
James

The temperature seems to be 150 degrees for 25 hours. If you want to reach Gene Wengert, he posts regularly on forestry forum.

You can't get the full sterilization at 120. 133 is the MINIMUM set by the USDA Forest service. https://www.fpl.fs.fed.us/documnts/f...chapter_20.pdf

The max temp was 145 for 48 hours. Hopefully that was good enough. The surprise was that it took twelve days to finish the load. Two of those days where for equalization. But I was surprised it took so long. There where two pieces of quarter sawn walnut that refused to go below 13%. But the spalted maple was starting to get too dry (5%). So I stopped it there.
James