Homemade Torrefication of spruce tops

Construction and repair of Classical Guitar and related instruments
grenner
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Homemade Torrefication of spruce tops

Post by grenner » Wed Oct 10, 2018 3:48 pm

Has anybody tried to do a Torrefication of a spruce top by his own?
Or does anybody know if this is possible and if yes how it can be done- homemade torrefication :?:

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prawnheed
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Re: Homemade Torrefication of spruce tops

Post by prawnheed » Wed Oct 10, 2018 8:06 pm

Torrefaction requires heating in the absence of oxygen. Unless you can find a way to fill your oven with nitrogen or another inert gas, it is not going to be easy to do at home.

printer2
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Re: Homemade Torrefication of spruce tops

Post by printer2 » Wed Oct 10, 2018 9:35 pm

I have done some spruce.Done in a convection oven at 385 F.

The bracing gives a color comparison. A six string uke I need to finish.

Image

I put the wood in the oven and step the temperature up to 250, then 350, first to dry out the wood then to soak the oven to equalize the temperature. Then I go to 385, about an hour should do. Gasses given off when baking and the smell of the wood is still prevalent the next time the oven is being used. I put a layer of aluminum sheet on a lower rack so that any radiation does not raise the exposed wood surface to a higher temperature than the other side. Not much else to add, I do have faith in my temperature display, 385 is about at the bottom of efficient treatment, lower not much happens and higher there is a danger of lighting something up. Not a bad idea to do a practice run first.
Fred

Stephen Faulk
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Re: Homemade Torrefication of spruce tops

Post by Stephen Faulk » Fri Oct 12, 2018 1:10 am

I deleted all my contributions to this topic. Please delete any quotation you've made of my content. My comments are being taken out context and it's not helping to clarify the subject.
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Stephen Faulk
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Re: Homemade Torrefication of spruce tops

Post by Stephen Faulk » Fri Oct 12, 2018 1:12 am

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Patience at the bending iron pays in rounded dividends!

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Stuart Christie
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Re: Homemade Torrefication of spruce tops

Post by Stuart Christie » Fri Oct 12, 2018 7:43 am

Experience is often mistaken for cynicism.

simonm
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Re: Homemade Torrefication of spruce tops

Post by simonm » Fri Oct 12, 2018 11:39 am

One difficulty is finding information. An internet search for something more scientific/systematic seems to yield only results about torrification of wood for biomass or marketing nonsense.

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Keith
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Re: Homemade Torrefication of spruce tops

Post by Keith » Fri Oct 12, 2018 6:05 pm

sounds to me that rubbing a little salt on wood to get the magic sound is less invasive that burning wood or have cows or people go number 1 on wood or using a guitar marital aid. I tried the salt method and discovered the salt in the little packets at McDonalds works best--on their fries but not on a guitar. :D

The original torrefication expert
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Stephen Faulk
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Re: Homemade Torrefication of spruce tops

Post by Stephen Faulk » Sat Oct 13, 2018 4:50 am

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printer2
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Re: Homemade Torrefication of spruce tops

Post by printer2 » Sat Oct 13, 2018 5:11 pm

I see no benefit to using a oxygen free environment if the wood is not at a temperature where it would react to it. Basically we want to distill wood and reduce the hemicellulose content. It is reduced at a temperature lower than the other major components of wood. It is the component that absorbs and liberates water with changes in humidity. Baking is sometimes used as the term used to doing the process, in any case the desired outcome is to reduce the percentage of hemicellulose in the wood. The reduction produces a gas that can be ignited. Off gassing at a temperature below the ignition can be done but it is slower than can be achieved at a higher temperature.

A major supplier of 'torrefied' wood for the US guitar industry does the wood in a standard air oven. Taylor guitars does their wood in a standard oven. I am familiar with the equipment as I spent a few years calibrating and servicing the type of oven and heat treating furnaces. My first experiments in baking wood had my samples in an oxygen free environment but eventually I learned that it is not needed for the reduction of hemicellulose as long as the temperature is kept below the ignition point.
Fred

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Re: Homemade Torrefication of spruce tops

Post by Stephen Faulk » Sun Oct 14, 2018 2:07 am

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Dirck Nagy
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Re: Homemade Torrefication of spruce tops

Post by Dirck Nagy » Sun Oct 14, 2018 6:15 am

Stephen Faulk wrote:
Sat Oct 13, 2018 4:50 am
The problem is not the joking around about guitar folklore. The problem is when the real science is ignored because a dummy perpetually gives false anecdotal information about something that is chemically impossible. It's not funny and attitudes like that which discredit science are destructive.

If you debunk a lie, the person who's been debunked should stand down. Trouble is idiots don't stand down, they double down on the unscientific lie. It makes me furious because I understand the premise of science methodology.

Anecdotal description and folkloric information had a place in the guitar culture, we all know that. But as guitar culture evolves and we learn more empirical information the parts of anecdotal information it debunks should stay debunked.

Rant over and sorry. I'm feel pretty strongy oppossef about anti-science attitudes.
Oh right, aren't you the guy who doesn't believe that gears allow for greater precision?
Stephen Faulk wrote:
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Gearing allows for finer tuning? I not entirely convinced of this.

Stephen Faulk
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Re: Homemade Torrefication of spruce tops

Post by Stephen Faulk » Sun Oct 14, 2018 6:20 am

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Patience at the bending iron pays in rounded dividends!

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Re: Homemade Torrefication of spruce tops

Post by Stephen Faulk » Sun Oct 14, 2018 10:32 am

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printer2
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Re: Homemade Torrefication of spruce tops

Post by printer2 » Sun Oct 14, 2018 2:53 pm

Stephen Faulk wrote:
Sun Oct 14, 2018 2:07 am
Ok cool. But if you bake the wood the in an oven without the control of the atmosphere then the process is NOT a torrefaction process. Again science, terms, goals. It all matters.
Torrefaction is the reduction of organic material to a charcoal like substance. No guitar wood is torrefied using this criteria. All guitar wood should be designated as baked whether it has been done in air, protective atmosphere or in vacuum. Although I have serious doubts that the wood is done in a vacuum as the temperatures are too low for efficient processing and the off gassed material would make a mess of the vacuum system.

Pyrolysis curves of hemicellulose, cellulose, and lignin.

Image

We want to use the area of reduction below 200 C to reduce the hemicellulose and leave the other components of the wood intact.
Fred

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