Air Dried VS Kiln Dried Lumber

M

macchips4

Well-known member
    I have read on various sites that air dried lumber is better to work with hand tools and the colors are better than kiln Dried lumber. Has anyone an opinion about this?
    I have a project coming up that wiil be veneered with pine being the substrate and case wood, and I was wondering if I should hunt down some air dried pine or just go to the local home center.I know of a mill in PA that air diries then after 1-2 years puts the lumber in a dehumidification kiln to bring the wood down to 6% mosture. Any Ideas or thoughts?
Joe
 
Joe, You might want to consider quarter sawn (or as close as possible) for your substrate, which will be hard to find at your local big home improvement stores, more than from a kiln or air dried. With that said air dried does seem to be easier to work.
 
Joe,

It some respects it is like cooking a rib roast. The finest restaurants let a roast stand until it reaches room temperature and then put the roast in a barely warm oven and let it seep in the heat over a long period of time, never letting the GRADIENT in temperature get too large; and at the end, they "finish" it with some higher heat, but still a low gradient because the internal temperature has by now , risen significantly. This has been shown to produce the most evenly cooked slices with uniform texture. Wnen the roast comes out of the refrigarator its core temperature is in the 40F area, fully 30 degrees less than the room temperature. Think of that process as equal to air drying a stick of wood before putting it in a kiln. If you slam the cold 40F roast in a 450 F oven as many home cooks do that is a 400 degree difference all at once and, you get black on the outside and purple on the inside.

In drying wood, starting off with air drying minimizes the gradient of moisture level in adjacent places in the wood. It stands to reason that this would minimize locked in stresses and presumably lead to more uniform physical properties in the finished wood when fully dried because the individual cells are more nearly at  peace with their neighbors in terms of environmental conditions, and hence stresses and strains.

Karl
 
    One project is a small work table, "seymour style". I guess for the pine sides and top it wouldn't matter as long as I can get quartersawn (or close as Jeff says). I think the sides would be not so wide to need to be veneered on both the inside and the outside to ballance the tension. The top .....I don't know..... probably both sides... or a lot of nails.
      but for a small chest of drawers made to match an existing bedroom set...in Walnut....I'll hunt some air dried to see the benifit of air vs dried. It too will have veneer accents but will mostly be solid wood. Now To get to drawing the plans.
    And thanks Karl .......now I'm Hungry!
Joe
 
Walnut in particular is one wood where you should be aware of the difference between what many outfits sell, which is steamed, and that which you can get from smaller air-drying/kiln drying operations who don't steam the wood.

JD
 
Johnny D said:
Walnut in particular is one wood where you should be aware of the difference between what many outfits sell, which is steamed, and that which you can get from smaller air-drying/kiln drying operations who don't steam the wood.

JD
Click to expand...

+1 for this reply - Walnut (Native American Black Walnut, that is) is the wood where processing seems to make the most, and highly visible, difference.  It's not so much that kiln drying itself damages the wood, but it's the common practice by the mills to use steam-injection at the start of the cycle to migrate the color from the heartwood into the sapwood.  The result is a much higher yield, but much duller colors overall.  Air-dried walnut can have various hues of deep blacks, browns and even purples.  The steamed variety is usually an overall dull gray color.

However, If I was building something out of Eastern White Pine (or, for that matter, wood from the hard pine group), I would actually look for kiln-dried wood.  The reason is that in air-dried lumber, the resin isn't "set" (hardened) in the wood.  That can lead to bleed-through around knots and other defects.  Kiln-drying is usually hot enough to set the resin, so bleed-through of the sap/resin into the veneer isn't an issue.
 
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