Kiln Dry Vs Air Dry

[grumpy bear]

I Bought Some 3/4" Thick Walnut Wood From A Guy Who Kiln Dries Everything. Then I Bought 3/4" Thick Walnut From A Different Place Where Everything Is Air Dried. I Might Be Crazy But The Kiln Dried Lumber Cut Better. It Seemed Like The Air Dried Was Alot Tougher To Saw Through. Is There A Difference Between Air And Kiln Dried Lumber?? Or Am I Just Crazy?

[GrayBeard Phil]

Nope, not crazy.

It would take an expert with a moisture meter to verify the two woods are of equal moisture content, and that the part of the tree (near the outside, or near the center) plus a few other factors to make the comparison fair.

It could well be the air dried was not down to under 10% all the way through. The sap was dragging on your blade.

Phil

[grumpy bear]

Thanks For The Info Phil! I Am Glad I'm Not Crazy. Lol

[workin for wood]

Lets remember that both these woods are walnut but from different trees. It can be that the air dryed tree was in a dryer environment than the kiln dried tree was, which would make the grain tighter. There's also the factor of how the two different boards are cut. Flat sawn is easier to scroll than rift sawn. And of course, could be the kiln dried is dryer than the air dryed. There's advantages and disadvantages to both. First thing though is that both those boards should be under %10, especially now that it is winter. Only a moisture meter will tell you that fact.

Kiln dried is better in that it is guaranteed to be under %10, in fact by law it must be in order to sell on the open market. But this sounds like a personal venture type of deal, not a lumber store type of deal, so who knows how a non-commercial kiln operator holds his standards. Only hardwoods are subject to moisture content rules, btw. Softwoods are not, and so you can buy a nice pine board at the box store and it might be %20 or more in moisture.

Anyhow, Kiln dried is best because it is truly dry. Bad thing is that there are alot of kilns in a big hurry, they over dry or cook the wood too fast causing internal stresses, checking, warping, twisting, you name it. They can do irreversible damage to the cell structure of the wood itself. This is a cause of concern for sure as your wood is not as stable as it should be. Kiln drying also guarantee's insect free lumber.

So then as some say, Air dried is best. It's a constant argument, but I'm on the side of the Air dry people. Air drying takes serious waiting time and constant re-stacking of your lumber. Your wood needs to be in a good environment too. No matter how you air dry your wood, you will not damage the internal structure of the wood. You can cause warpage and twisting by not properly stacking, but the wood isn't technically damaged. It does take some extra steps to get it down under the %14 mark, which is generally where air dry likes to stop. A de-humidifier and some plastic wrap will solve this problem. I have all kinds of lumber that is air and kiln dryed, and I find that the air dryed lumber cuts better.

If you think about it...look at all the beautiful furniture and carvings that have lasted for many centuries and now sit in museums around the world. Those are all air dried lumber. You don't find kiln dried lumber that stacks up to it, and likely never will. Today you still find great artists, carvers and turners around the world, and they too find their way into museums and art galleries, and a majority of those too are air dried lumber. Seems to me that I develop a more personal relationship with my wood when I cut it and dry it on a shelf in the shop.

[Andy]

Wow ... very informative thread that I find quite interesting. Thanks for the question and the replies. Good stuff!!

Andy