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sorry to everyone about posting my jig picture.
I messed up somewhere!
Not enough coffee
Mike

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Mike Collins

Brock, I once got some great advice from a VERY BIG NAME. He told me that intuition is a big part of building. If it feels right then run with it. I had a douglas fir top that for some reason I wanted to bake. Not sure why, it just felt right. It oozed and leaked pitch all over my wife's oven. So I got to spend the better part of an afternoon with a can of Easy Off and a schotch brite pad.
Not sure if the baking did anything productive but the negative effects were enough to deter me from doing it again. (I really don't like cleaning baked sap from the inside of an oven)
Still curious: aren't you worried about your glue joint?

BRING ON THE KILN DRIED WOOD

Kiln drying involves both heat and moisture, and never takes the wood down to 0% moisture content. It is very different from "baking" in this instance.

It's not about tone, setting pitch, or anything else. It's about bringing the wood down to its minimum possible dimension, then letting it come back up to its proper moisture content. Done correctly, the wood is much less likely to split and crack if expeosded to an ectreme dry situation later. It also shows any possible weakness, wind shake, etc..., in the top BEFORE you build with it. It also will reveal any hidden pitch pocket(s) before you go further. It does not affect tone!

Oh, and the high end woodworking community has long known of this, only they don't call it baked wood, but stabilized wood. Many is the woodworking shop with a "hot room" for its wood stocks.

Don't knock what you know not of.

Paul, sorry to hear of your pitch oozing episode. Douglas Fir will always do that, so this is one wood you never want to bake. 100 year old Doug Fir timber will still ooze pitch when cut. Well known fact.... Rest assured that spruce will not make a mess. In fact, I've never has any pitch come to the surface of any spruce top, unless there was a pitch pocket I hadn't seen in the candling. I'm wondering if those who see pitch come to the surface of spruce aren't baking at too high a temp.Mario38999.4054513889

[QUOTE=Pwoolson] Still curious: aren't you worried about your glue joint?[/QUOTE]

Funny story... I have a similar one with a pot of hide glue I forgot on the stove....oops...

I am going to leave the tops full sized and raw when I cook them, then joint/join them. It just seems easier to do it that way.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Preshrinking the plates before they are adhered to the sides makes intuitive sense to me.

Give the wood a chance to shrink and expand to its extremes while it is relatively free to move in the longitudinal and lateral dimensions.

I don't know enough about any of this to make an educated opinion on wether those benefits are long term or not but there is a lot to be said for intuition sometimes even we we don't understand the science behind it.

In this case there is no real added cost so why not?

[QUOTE=Brock Poling]
What did I say? You seem to be ignoring the part where I said this has nothing to do with my normal drying or stabilization process. All of that is the same. Gheesh....

and.... regarding the big names... I agree that you should not be a lemming and do it simply because they do. However, there is a lot of good evidence to support that cooking the soundboard helps AND they do it (and I presume they actually know a thing or two about building). So usually, where there is smoke... there is fire.

[/QUOTE]

I am not ignoring the fact that you did not suggest that this takes the place of normal drying. But let's face it, this whole thing DID come about to address the fact that there was not a supply of 20 or even 10 year seasoned top wood to meet the needs of the big factories. And while this process appears to give at least SOME of the benefits of long term seasoning, it started as a cost effective and efficient thing to meet the needs of some of the large scale manufacturers (and maybe not a bad piece of marketing hype ).

But, does this make it a preferred thing for smaller scale hand builders? I don't think anybody has the answer to that question. As for good evidence to support that cooking helps, now that is a stretch, at best. Yes, there are some before and after measurements of tone, stiffness, etc., but, hey, any time that you make a substatial change in moisture content of a piece of wood, these things will change. Now take that cooked wood back up to 15 or 20% moisture and see what happens (and, yes, sometime in the life of that guitar that will probably happen). For any meaningful research on the subject, I think one needs to take matched sets of wood (maybe cut soundboard pieces into two lengths) and cook one half of the sample. Then do the measurements and run the samples through a series of moisture cycles over a period of a couple of years, taking the same measurements periodically. And see what happens. I don't think anybody has done that.

If cooking DOES permanently shrink the wood, you have probably done some damage at the cellular level and I am not convinced that this is a good thing.

So I am not beating on anybody. I am just saying, let's keep the facts separate from the fiction, and not leave our common sense on the doorstep. And yes, lets not become lemmings, or sheep, or rats leaving town

Grant

and maybe not a bad piece of marketing hype

Ummm, nobody that I know of that does this, factory or hand builders, even mentions it in their marketing/advertising. It's something that got discussed in private exchanges and came about quietly. Fact was, I was doing it, for the right reasons, before I found out Taylor, Collings at al were also doing it.

As I said, high end woodworkers have long done it. My family has always done it. It's also been known for centuries that bringing wood down to 0% moisture makes it more stable to environmental changes. This ain't new news, fer cryin' out loud; it's old hand. Wake up.

And no, it doesn't replace seasoning. But even well seasoned wood still can benefit. In fact, we should not bake green wood at all. Doing so messes it up. This is not kiln drying. Only do it to wood that is already seasoned.

I'm just curious about which light bulbs will create a safe hot box 200*f for several hours

There's no better marketing hype than a "secret" process that "leaks" out Larry Davis38999.4415162037

The 60 watt bulb in my home's oven will bring it to 120f and hold that all day. I'd suspect two would do fine. Safety? As long as it's all wored correctly and not touching wood(IE: built with a degree of intelligence), it should be safe. Still, I just use the oven....

It ain't marketing. Again. It ain't marketing. Some of yus simply don't like seeing cracked tops on our guitars. I have yet to have a single crack, check, or split since adopting this method 8-9 years ago, and some of these guitars are severly mistreated..... Not marketing; just good practice. I'd also be ready to bet you can't find one of my clients who knows I cooked his/her top. Not one(unless they read this, but I imagine none do)

   The effects of temp and humidity changes can be limited to a certain
extent by cooking tops. The dimensional changes that occur when the
relative humidity changes and the tops begin to either absorb or release
moisture are determined by the top's ability or inability to do so.

    By cooking the tops, the ability that they have to absorb moisture is
affected since resins or pitch is set or as some have siad, crystalized
through hardening by the heat and cell structure is solidified beyond what
natural time sesoning will cause.

    Professional kiln services that operate in service to that larger
woodworking industry provide some of these effects through their
complexed and closely monitored sequence of applications of heat and
moisture changes to the environment that the wood is processed in.
During that process, the wood is heated and alowed to cool while, at the
same time, the moisture content of the wood is reduced and elevated
through the introduction and removal of moisture in the kiln
environment.

    Not only are the resins set and hardened to reduce the wood's ability to
absorb moisture, but the dimensional expansion and contraction
parameters are stretched and pushed to create a more stable piece in the
end. As the wood's ability to absorb moisture is inhibited, it becomes
much more stable since the expansio that occurs when wood does so is
eliminated to an extent. Once wood can no longer absorb the amount of
swelling or expansion causing moisture, the effect to the other end of
dimensional change or shrinking is controlled, in turn.

    Some of the best builders in the world, both large and small, are using
ovens or a type of hot box to heat their tops....after natural time induced
sesoning has been accomplished. You can't argue with the quality of their
guitars or their reputations for quality.

    All of my wood, both top and back/side, goes through a tightly
controlled kiln process of moisture removal and injection as well as
temperature level changes at my kiln guy's facility to do just these things
or I would be building an oven of sorts in my shop to do it here. The
facility that provides the service is one that treats wood for a few of the
largest furniture manufacturers in the world and their furniture has stood
in homes all over the world for generations without falling apart or
warping and cracking.

    Stability and longevity are the goals of these heating and drying
processes and this simple oven exposure for tops in guitar does provide
definite benefits.

   Cook them Brock, and you may never notice or be able to document the
actual benefits, but you'll most likely avoid some of the pitfalls of using
uncooked woods as they expand and contract with environmental
changes. It's just like insurance....you hope you never have to use it, but
it's good to know it's there.

Regards,
Kevin Gallagher/Omega Guitars Kevin Gallagher38999.9875578704

Thanks Mario and Kevin, i stand educated! great thread and glad everyone stayed courteous up untill now.

Softwood (conifer) resins must be heated to a minimum of 175F to crystalize the resin. This process occurs over years naturally and maybe that's why spruce tops "open up" with age    Setting softwood resins in a kiln schedule is primarily done to eliminate bleed thru of painted surfaces

Hardwood cell structure is entirely different than softwoods and do not do not have resin or pitch pockets to deal with because they have no resin canals. This would be true of almost all hardwoods, but there are some exceptions.

Wood can case harden above 212F.

What is you recipe for various woods? Spruces go for 30minutes at 200F. What about koa, walnut, mahogany etc? Do they get a different recipe?

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

All this makes me want to make a guitfiddle outta a light'n tree just for the Mojo.

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"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=SteveS] What is you recipe for various woods? Spruces go for 30minutes at 200F. What about koa, walnut, mahogany etc? Do they get a different recipe?
[/QUOTE]

I have only heard of people doing this for tops.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

All moisture is gone at 212(water turns to vapour..).

I bake at around 180f for an hour or less, then leave the light bulb on(120f) to cool it slowly back down, overnight. A hygrometer in the oven shows low single digits, even at 120f.... then back to the stack until needed.

No idea if this is ideal or not, but it works for me.

Join after baking. Long after...

I only bake softwoods, but, we all cook our sides, don't we?

Brook,
In Kevin's post above, he says he does his backs and sides also.

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

Brock asked about making a hot box to bake tops. And them the, should you bake your tops thing starts and off we go with a ton of I think this and I think that. Everyone do what you like when making your guitars. And if someone asks for some help give it so him or her. I think some folks just like to stir it up.

So brock, A hot box is a great idea!

Or just do a half a top at a time in your oven.

[QUOTE=Mario] ... we all cook our sides, don't we? [/QUOTE]

And once cooked, they stay in the shape in which they were cooked.
Moreover, to cook sides, don't most folks increase the moisture level? So,
this seems very similar to the oven cooking procedure.

This sure flies in the face of the preference for air dried wood... or so it does
to my inexperienced mind.

Did someone say 'hotbox'?   

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

Brock your not alone, I've been researching how to go about baking tops. I think Kevin got it right, and from everything I've read cooked tops are more stable. I was thinking of a hotbox run by lights or a heater of some type, with a good flat clamping system to hold the tops while baking. Also need to consider moisture effect and how to vent that out, if you ever see video of Taylors process they get tons of water out of both their tops and rosewood they cook. I'm not interested in backs and sides just yet but tops yes, I read Brian Burns report on it and I'm sure Al Carruth will be along as well and can talk about it.

Mario also has the right idea, cook them and then let them for a long time so they stabalize before you build with them.

Like I said I've not done it yet but I'm heading that way, it's been on my to-do list for a long time...

Cheers

-Paul-

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-Paul-

Patriot Guitars

Is I possible that a fingerstyle guitar built out of air dried timber and braced just right would have a certian openness that the same guitar built with kiln dried wood might not?
Is klin dried and baked a little beter for flat pickin and a little boom-ckucka?

Honestly I don't have the experiance to say. It is part of the artraction to think about and try to intuit!

_________________
"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...

oops make that better

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"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...

You guys use Bake-n-Shake or just bake unseasoned?

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com