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Someone mentioned seasoning wood by keeping it in a humidity controlled environment for years. I think this is mistaken. "Seasoning" (the word) comes from exposure to the change of seasons. The more the wood has been responding to environmental changes before being used the better. I bring sets into the shop a few months before I expect to use them. Until then they are out of the rain, but without temperature and humidity control. If I lose a few, well, better that they revealed themselves now rather than later.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I think I may need more surface area on my head to scratch...

I would think the biggest problem with irregular grain would be irregular shrinkage. In some flat sawn you have areas that shrink differing amounts or in differing directions. Of course if you're a newbie like me and you build a guitar in the back shed during rain, then bring it in to an over heated room when done, the sitka spruce will likely crack, and then you can turn it into an instant "virtual vintage" guitar, using Behlen toner (the secret to good tone). Ha ha. Sorry I'm in a weird mood.




all the cracks are repaired, and everything sounds good... But I'm talking top instead of back here. (this top has a lot of character and looks like it was built a long time ago)...

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"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.

Try seasoning sets outside in Buffalo NY. I guarantee you'll wind up with a lot of kindling.

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YIKES! That's a pretty harsh statement there, Haans. Seem to me that keeping a beautiful guitar in its case except when it’s being played is akin to keeping a bouquet of roses in the box they arrived in, except at dinner time.

I see you decided to man up and get rid of the political endorsements in your signature?

+1

"Conditioning" is a stage of the kiln 'drying' process and has nothing to do with seasoning/aging. It reintroduces moisture to the wood surface the purpose of which is to to equalize the MC of the kiln dried timber preventing cellular collapse and or casehardening of the wood surface.

Cheers

Kim

Absolutely right, howard.
An hour ago I pulled some wood for my next 3 builds.
Tazzie Blackwood back/sides/top. One plate had a tiny knot, 1/16", and it developed a 3" crack up the grain.
Looks like I'll be doing a spruce top, Tazzie back and sides,
and make something else that's smaller with the kindling.
Maybe it's Kizmet that the piece cracked.
I think I like a spruce top better anyway.
I've had that wood for about 4 years, maybe more.
Wood does what it wants, and I'm glad I waited!

What the heck is that, a bong ?

L.

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Cut to size.....Beat to fit.....Paint to match.

"Shrinkage/expansion in a quartersawn board is greatest across the width of the instrument"



sorry, but this is not the way of wood....


michael keller
www.kellerguitars.cpom

That would depend entirely upon whose eyes are reading the word I think Todd. Long before kiln processors hijacked the term 'seasoning' to describe their process, no doubt because it does have the "delightful tang" you refer to which helps gloss over the minds eye view of wood being forced into a state of usable MC in a matter of weeks when once it took years, the standard term for drying wood was to 'season' simply because the process required exposure to the changing seasons over a period of years.

As I mentioned in this topic, http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=31089&start=25 maybe it is an American thing and I suppose ur gonna get that on a forum which calls itself the "official luthiers forum" when it has such a large contingent of Americans, but it seems in Australia we can buy wood described as "kiln dried" or "air dried" and from this state it can then be described further as having been seasoned for x number of years, thus using the term seasoned to describe the passage of time since the wood was first taken to a usable state of MC by either method.

That said it does not prevent some processors here in AU from using the term to describe there product as "seasoned timber" as soon as it is removed from the kiln, but I maintain it is they who are knowingly in error purely for marketing purposes and I will continue to use the term in the context that I know to be true and correct regardless of their influence or anyone else's.

Cheers

Kim

On the flatsawn thing. I was going to do a build around the 100 dollar challenge, and I was thinking of some very capable, but unremarkable Maple I have. Actually might be something different, since I think any maple is really beautiful. Anyway, my thinking is, that if one is OK with an epoxy undercoat, then do both sides. That along with binding attached with crazy glue, pretty much takes the moisture transfer, or at least rapid transfer, issue out of the equation. An epoxy that is 100% solids will pretty much turn your wood into plastic moisture wise. In real terms if you put a sealed piece of wood in a humid zone, it will eventually come to the ambient moisture, but it will take a long time.

On the sanding thing, considering the source I would be suspicious of the tech cred. But the test is simple. Get two samples identical except as to sanded surface. Make sure the ends are sealed with epoxy. Put them in a moist environment, then after a week, take them out, and weigh them over time, and see which reaches equilibrium first. Since that is a pretty simple test to do, it should be the case that circulated info would be accurate, but I wouldn't bet on it. It is a non-destructive test, so: a) you could do it with two full size pieces like unglued back panels and b) you could then swap the pieces so the sanding was reversed and run the test again.

Kim, I don't know that there is anything untoward going on as far as the manipulation of the term is concerned. The reality is that for certain uses there is no difference in outcome where either process is concerned. Then as you move out towards the behavioural fringes, the users develop preferences that are related to many different ends. Say green woodworking, or people who are concerned about preserving subtle colours, or people who are concerned with tensile strength, stability, barkability, etc... All different uses. Then it becomes a big issue as to how the wood is processed. But most users don't care, so nothing misleading is actually happening when terms are substituted.

thanks Todd, Much appreciated

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Beautiful and unusual tone woods at a reasonable price.
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The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

TomDI brings up a interesting thing that I have often thought about. This is what is a certain woods propensity to take on moisture after it has reached a reasonable EMC.
Wood movement is usually measured in 3 categories (at least as far as woodworkers, guitar builders talk about.) Volumetric shrinkage, tangential and radial movement.
This is usually from green to oven dry. You can get a pretty good story about a particulars woods stability by looking at these numbers, of course a perfect piece of a "unstable" wood is better than a gnarly piece of a "stable" wood but you get my point. I look for low overall numbers in these categories plus a T/R ratio that is more towards 1 to 1 . A low volumetric shrikage coupled with a low value and close to 1 to 1 T/R ratio is a pretty good indicator.
But there is another question that can be asked and that is what I stated above. What is a particular woods propensity to take on moisture after is has been dried ?
A interesting example is Ebony. It has a volumetric shrinkage of around 20%. This is huge ! but it's T/R ratio is almost 1 to 1. This is optimal. So the question this raises is, is Ebony stable after it has been sufficiently dried ? Once thoroughly dried does it take on water and try to return to it's old volume. This is a simplified and rhetorical question. It will never return to it's green volume but you see my point. As Tom suggested these would be pretty easy experiments to conduct. I always wished that those wood charts had this kind of information.
The experiment I have in mind would take various woods that were cut to a precise size and dry at a low EMC and expose them to high humidity. At intervals of time the wood would be measured for size and weight increase. This is what is done right now but it is done the other direction from wet to dry. I think it would be highly informative to go from dry to wetter.
Yeah I know, blah, blah, but I am home with the flu today.
L.

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Cut to size.....Beat to fit.....Paint to match.

Link that sounds like a worthwhile endeavor. We have lots of scraps if you need any.
Get better soon.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

What size were you thinking of Link?

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

It appears that in attempting to be non-technical, I created confusion in my description of humidity-induced movement of quartersawn vs. flatsawn woods. Michael, you know me well enough to know that I actually have a clue about wood movement. The error is in the way I said it, not in my knowledge. I don't think I would answer you with such a brusque reply.

I'll try to make my point more clearly.

The question about flatsawn wood raises the issue of the ratio and effects of radial and tangential shrinkage and expansion. Longitudinal changes are minimal and are generally ignored in guitar bodies. My point is that radial shrinkage in quartersawn soundboards and backs is fairly predictable. Bracing and arching the plates are attempts to cope with that movement. Tangential movement is moot in purely quartersawn plates, changing the thickness evenly without affecting other dimensions -- but not in flatsawn ones. Tangential movement is always (according to both Hoadley and the Forest Service Wood Handbook) greater than radial shrinkage, averaging about twice as much (the Handbook has an extensive table of values). Flatsawing introduces an element of movement that luthiers have difficulty addressing since it can be difficult to predict, creates movement across the plates, and is a large value. Backs get wavy, braces come loose, cracks develop, customers and builders get grumpy.

That's all I meant.

If luthiers feel they have to use flatsawn back wood due to customer demand and availability, maybe they also have to accept a new paradigm for working with it.

Some suggestions
-Assembling drier than the commonly accepted RH
-Pretreating the wood before bracing (baking, cyling though differing weather or other drying methods?)
-Excluding any shrinkage cracks from warranty provisions (as do the big makers)
perhaps wording"this guitar was assembles in X% RH conditions, exposure to very dry conditions may cause cracking and this is not covered by warranty"

Any others?
I don't think just treating it like quartersawn and hoping for the best is good enough.

Rick, you stimulated a good thread though.

Ken,
1"x1"x1" blocks. Have to take wood to oven dry, then cut them and measure. Do this quickly and in as dry a envounment as possible. Then expose the samples to a constant known temp. and humidity level that would eventally take the samples to a predictable EMC (based on the constant temp. and Rh.) Measure at , I don't know, every 6 hours. Might be better to cut the blocks at 1x1x3". Less end grain to side grain. There is another possible variable. Some woods might really take in water through the end grain but if the end grain was covered that same wood might take it in slower than another wood that was slower to take in water with end grain exposed.
Interesting that on most guitars the only end grain that is usually exposed is the end of the fret board and the sound hole. A lot of builds cover those as well.
L.

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Cut to size.....Beat to fit.....Paint to match.