Kiln Dried vs Air Dried

[Jim Fox]

Is there any difference in working with kiln dried compared to air dried? I've only done my limited projects with kiln dried.

[Jim Becker]

No difference. What you want is "correctly" dried lumber...the method doesn't matter, frankly. Most of the lumber I use is air dried.

Some species, such as walnut, are better looking to many of us when air-dried as they typically get steamed when kiln dried to get higher yields and that removes a lot of the wonderful color variations.

[Neal Clayton]

that and some species prone to split will do so to a greater extent when force dried, rather than naturally dried. i primarily mess with old growth longleaf pine and it's one such species. lots more surface splits if you force dry it, not so much if you let it air dry.

[Chris Padilla]

We humans are an impatient lot! Mother nature likes to take her time to do things. However, we humans are a crafty lot as well! Usually slow and steady wins the race....

I think most have HEARD that air-dried walnut is superior in terms of color compared to kiln-dried walnut but I wonder how true it is. I don't think I've ever seen an "official" study one way or the other....

[Frank Drew]

I really like the quality and working properties of the native lumbers I've air-dried myself, but because of the realities of the marketplace I've used much more kiln-dried than air-dried and the work hasn't suffered for it.

[Jim Becker]

Originally Posted by Chris Padilla

I think most have HEARD that air-dried walnut is superior in terms of color compared to kiln-dried walnut but I wonder how true it is. I don't think I've ever seen an "official" study one way or the other....

Easy to test...buy a piece of kiln dried/steamed walnut and a piece of air-dried walnut. Night and day when it comes to color and interest, at least to my eyes! The steaming makes both the sap and the heart the same "brown" color where the air-dried walnut has a tremendous variety of hues throughout from golden through deep purples and hints of green, depending on the particular tree and the conditions from which it grew.

[Cliff Rohrabacher]

If you are steam bending the wood, Air Dried is way better.
Otherwise it's just a question of moisture when you mill it.

[Chris Padilla]

Originally Posted by Jim Becker

Easy to test...buy a piece of kiln dried/steamed walnut and a piece of air-dried walnut. Night and day when it comes to color and interest, at least to my eyes! The steaming makes both the sap and the heart the same "brown" color where the air-dried walnut has a tremendous variety of hues throughout from golden through deep purples and hints of green, depending on the particular tree and the conditions from which it grew.

I guess I never know if the walnut I'm looking at is a.d. or k.d. My own personal stash is a.d. and does contain those wonderful purples and greens but not all a.d. gets this way.

[Chris Padilla]

Originally Posted by Cliff Rohrabacher

If you are steam bending the wood, Air Dried is way better.

Why is that?

[Dave Lehnert]

If antiques are still around that were made before kiln drying. Air dry has to be a very good option.

[Jason Beam]

Originally Posted by Chris Padilla

Why is that?

When kiln drying, the lignin between the celulose fibers tend to get more brittle. I'm not sure if it's a function of forced drying or overdrying or what. The steam (and other methods) of bending all do markedly better with air dried stock.

I think what happens is that with air drying, the moisture is free to find its own path out where a kiln makes for a lot of steam pressure inside the cells and this just rips those all-important connective tissues to shreds.

[Jim Becker]

Originally Posted by Chris Padilla

Why is that?

Chris, kiln drying "modifies" the lignum (sp?) in the wood fibers because of the heat, which reduces it's ability to bend well when using moisture/steam to do so.

[Charlie Plesums]

Originally Posted by Jim Becker

Easy to test...buy a piece of kiln dried/steamed walnut and a piece of air-dried walnut. Night and day when it comes to color and interest, at least to my eyes! The steaming makes both the sap and the heart the same "brown" color where the air-dried walnut has a tremendous variety of hues throughout from golden through deep purples and hints of green, depending on the particular tree and the conditions from which it grew.

I believe you, but I wish I could get steamed walnut here in Texas. The stuff at the lumber yard has so much sapwood it is sometimes hard to identify as walnut. That is why I buy my walnut when we visit friends and family in Iowa/Minnesota. Not fun to bring 1000 pounds of lumber (the load limit my mechanic suggests for a 1000 mile trip) south each year

[Larry Fox]

Charlie, if you ever make it up to SE PA definitely take an empty truck to Hearne Hardwoods. Walk inside the big door and turn right, the 4/4,8/4 walnut in the bins there look like big wide slabs of dark chocolate. Tough to get mesquite up here though - gotta use hickory or apple in our smokers.

[Ben Davis]

Krenov's Art of Fine Cabinet Making goes into a small rant about kiln drying. At the time the book was published he was not a huge fan due to loss of color and texture in the wood. Just FWIW.