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Seasoned bake seems to be popular

There has to be benefits to baking spruce even if it's a new procedure and untested long term.

I started baking my tops (spruce only) about eight years ago. The
immediate thing I noticed is that, like Mario, I never again have had a
spruce top develop a crack. Nor have I had any further issues with pitch
pockets. As a result, I do believe that it really helps the integrity of the
wood to bake it.
Sound is so subjective but again, I believe that my guitars sound like well
broken in instruments from the day they are strung up. I directly attribute
this more instantaneous response to the baking of the top. This is strictly
a subjective response and others may disagree. But for me it works.
SPECIFICS: I bake in a used oven (thrift shop for $15.00) at 200 degrees
for one hour by timer. I then let the top stabilize for a week or so and
then glue it up and use it.
At this point in my career, my intuition says it works; so I would not build
an instrument with a spruce top that was not baked.
Others may disagree but I put this info out there for those who want it.

_________________
Sylvan
http://www.wellsguitars.com

Boy, long one.

I think there are a couple of things going on in this. One is setting the resins, and the other is probably reducing, and perhaps stabilizing, the hemicellulose.

The structure of wood is made up mostly of three things, cellulose, which is about half the weight, and a mix of equal parts of hemicellulose and lignin. You could think of the last two as a glue and a filler. Both cellulose and lignin are pretty stable chemically, but the hemicellulose, which is a branched chain polysaccharide, can break down over time. According to one study, done by furniture conservators the hemicellulose dissappears at the rate of about 1%/decade I am still unclear as to whether that's 1% of the total weight of the wood, or 1% of the hemicellulose).

Hemicellulose is the part of the wood that adsorbs and desorbs moisture from the air, so as it dissappears the wood becomes more stable. The density also drops, as does the stiffness, but the density goes down faster. Very old wood that has lost a lot of hemicellulose becomes opaque, owing to the spaces, sort of like a snow bank.

I think that baking the wood cooks off most of the loose ends, so to speak, of the hemicellulose, making it more stable, at least for a while. Whether the effect is permanent is hard to say, at least based on the little I know about it.

Some violin makers achive about the same result by 'stewing' wood; simmering it for a few days in water. A certain amount of sugar gets cooked out, the wood is lighter and more opaque, and more stable.

Al -
Thanks for giving me the scientific answers for what I have been observing!

_________________
Sylvan
http://www.wellsguitars.com

Umless you have an accurate thermometer, don't push for 200. Aim lower, and leave it in longer. Same results, as far as I can tell. And safer(for the wood). Even 150f will show near zero RH. Prop the door open about 1/2" to let moisture out of the oven, BTW. Yes, both halves on the same rack(center). I use spruce stickers on the grilling, to prevent staining. I don't weight my wood down, but then, it's already well seasoned at this point. If it still wants to cup now, I din't want to use it on a guitar, anyhow.

As for sound, I still hear a big change on my guitars when I run across them years later, so I know they don't come out of the box bearing their full potential, and I'm glad they don't. I've also built a good handful without baked tops(sometimes I'll forget, sometimes, other reasons) and none of these have sounded different enough in any manner of response to make me think that the baking affected the tone.

Hesh -
I do exactly what you described in your post. I have never had the wood curl
on me. I agree with Mario-if it curled I would not use it in a guitar. I do not
weight the wood. I just place it on the (clean) grill surface. I use an oven
thermometer viewable in the door's glass to insure the oven's temperature. I
have never had spruce "drip". I do not stack two halves but place them on
separate shelves as you describe. Try it, I think you will be pleased with the
results!

_________________
Sylvan
http://www.wellsguitars.com

     I have cooked my top woods, but not my back/side woods. I'll heat
tops at 190 degrees for one and a quarter hours in the oven and alow it
partially cool before I sticker it in my stock to finish cooling and settle in
until i use them. Most of the tops I build with have been in my shop for
several years, but some vendors send material with great low moisture
content that allows the wood t be used much sooner.

    In my post above, I said that all of my woods go to my kiln guy who
has large vacuum kilns and handles the wood drying for large furniture
makers. He doesn't offer his services to guitar makers, but is a close
friend and runs my woods along with his loads of large lumber. With the
size of my wood being so small in comparison to what he normally
handles so it serves more to fill open spaces in the stacks than as a full
load.

    I don't think any harm would come from cooking backs and sides, but
you'd need a substantial oven to fit side length bpards in. We do cook our
sides through bending and i'm sure there's a certain amount of effect
presented by that heat.

Regards,
Kevin Gallagher/Omega Guitars

[QUOTE=Hesh1956] Mario and Sylvan many thanks I will be doing this on my tops going forward.[/QUOTE]

Ditto...Alain Desforges39000.0682175926

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

I've baked cedar,,, but it wasn't usable afterwards because I couldn't get the salmon oil out of it..

But to add just a little to this, two other options might be either an electric charcoal starter or a heater from a smoker, both of course with a thermostat. I'd probably go with the smoker heater, that way the salmon would taste great.
Mike mikev39000.0887962963

Great thread indeed guys, thanks!

[quote=mikev]I'd probably go with the smoker heater, that way the salmon would taste great.[/quote]

I think your missing the point! How would the salmon sound?

    That reminds me of a stabilization process used in steel that involve repeated heating and cooling the steel. Just as conjecture, would numerous repeat of process accelerate the hemicellulose conversion as per Carruth's statements.

    Another potential would involves freezing the wood perhaps with dry ice or vac-freezing. These would be interesting experiments. This hemicellulose conversion may simulate seasonal variances, vis-a-vis 10 cycles equaling 1 decade, per se.

     Possibly, combining the two processes add to the complexity, but would be interesting to observe.

_________________
Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

That salmon's gonna sound smokey!

If you are interested in making a hot box, do a search for laminated bow making. Almost all the laminated bows use an epoxy that cures in heat. This is the only site I can remember off the top of my head   heat box.

_________________
Aoibeann

I would not I repeat not cook sides. Why chance making them more brittle before bending.

_________________
"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

[QUOTE=Billy T] Another potential would involves freezing the wood perhaps with dry ice or vac-freezing. These would be interesting experiments. This hemicellulose conversion may simulate seasonal variances, vis-a-vis 10 cycles equaling 1 decade, per se. [/QUOTE]We can artificially age materials by holding them at higher temperatures. This is often done for medical devices. The FDA allows it for establishing shelf life/expiration data, but they always require a follow up with real time to verify. That is becasue it is not 100% reliable.
It would be interesting to do, but it would be very difficult to prove with wood instead of metal and plastic like I am used to dealing with.

_________________
"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

[quote=SteveS]It would be interesting to do, but it would be very difficult to prove with wood instead of metal and plastic like I am used to dealing with. [/quote]

Yes it's kind of a shame! The kind of testing for steel far exceeds testing for wood as I've seen. Especially in dealing with tonal qualities. Specific densities, elasticity... are well recorded, but what does this mean in relation to sound? Also how would one quantify the improvements.

   I've got the wood for a jig that will clamp outside a soundboard which I plan to mount a neck and do some work on variations of proceeses. Bracing, thickness, different radiuses... and other configuration, but one has to start with consistant SB's in the first place, to measure differences. There's so many variables. Isolation and control subject is almost impossible.

Hey! Maybe that's why it isn't done!

_________________
Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

[QUOTE=SteveS]We can artificially age materials by holding them at higher temperatures. This is often done for medical devices. The FDA allows it for establishing shelf life/expiration data, but they always require a follow up with real time to verify. That is becasue it is not 100% reliable.
It would be interesting to do, but it would be very difficult to prove with wood instead of metal and plastic like I am used to dealing with.
[/QUOTE]

A basic rule of thumb in chemistry is that you double the reaction rate of any given chemical reaction for every 10 deg C rise in temp. This premise is used for accelerated life time testing in lots of products, especially electronic components. They can also control the humidity in the environmental chambers that they conduct the tests in.

This is not hard to do for any material, it's all about what parameter(s) you measure and how you measure it when you're determining the effectiveness of your accelerated aging regime. That's the tricky bit.

Brian Burns decided to measure Q his results show higher Q values after baking - this is a good thing. But as far as I know he only measured so that he could determine this one value, there maybe other parameters that could be measured that would show baking wood is not a good idea. Until someone does the experiments the debate will continue.

Ah yes! of course, now why did'nt I think of that?



So bloody obvious when you look at it

Hey, was'nt that "Q" guy James Bond's Geeky side kick?

Cheers

Kim

[QUOTE=larkim] Ah yes! of course, now why did'nt I think of that?



So bloody obvious when you look at it

Hey, was'nt that "Q" guy James Bond's Geeky side kick?

Cheers

Kim
[/QUOTE]

E = MC square and now i'll go get me an aspirin, too much thhhhhhhinkin'!

No..."Q" was part of the continuum in Star Trek: The next generation!

OK, I am now a "Wood Baker", thanks to all for sharing their views. It makes perfect sense. I think I will go for the 150 degree for 1 hour program and hope I don't find that all my tops I have been receiving satifying my WAS is not junk and cup out on me.

Thanks

Mike

Hi Mike,

Let us know how it goes please!

E=Fb for us musicians ...

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"