Air dried vs kiln dried

[Bill Tindall]

The experiment:  Typical 8/4 piece of fresh sawn walnut plank.  Split to make 1" pieces.  Steam one.  After steaming KD the steamed piece.  Air dry the mate.  Set in south exposed window in eastern Tn for months of June and July.  Photograph. 

More data.  Period furniture would have been made with air dried lumber.  Even see any reds in it after a century or two?

More data.  Any walnut not colored during finishing will bleach to a light beige after a few years by a sunny window.  I refinished a lacquered walnut conference table that the owner thought was some different wood because it was so light, about like aged ash.  

If the walnut will be stained the color before staining hardly matters.  If not stained, or oiled which creates color,  the reds are fleeting upon exposure to sunlight.  It is for this reason I always stain my walnut pieces with burnt umber mineral pigment stain.  (burnt umber is a redish brown pigment which provides a natural looking color to walnut.  )

I should note that after steaming the surface of the walnut is sooty black like it has been charred.  Steaming can be short and hot under pressure or a few days in a sealed environment with steam added .  Small pieces can be readily steamed in a canning pressure vessel.  The color does not migrate from heartwood to the sap wood.  Rather the sapwood turns dark under the influence of heat and water.  

I had a friend that ran a furniture factory.  He claimed that steamed walnut worked better with fewer machining defects.  This observation could make sense.  A walnut steamer smells strongly of furfural indicating some chemical decomposition of the wood.

[Stwood_]

I've always used kiln dried. When in business, I did not need something shrinking up, especially door panels.

[2Goober]

I always use kiln dried because I lost quite a bit of cherry many years ago to worms. I'm lucky because I have a source about 1 hour away that has really good prices. They make furniture parts and have on site kilns. Odd combination but it works.

[iclark]

I always use kiln dried because I lost quite a bit of cherry many years ago to worms. I'm lucky because I have a source about 1 hour away that has really good prices. They make furniture parts and have on site kilns. Odd combination but it works.

What part of the country are you in?

When the server and software changed the member locations got lost.

[iclark]

The experiment:  Typical 8/4 piece of fresh sawn walnut plank.  Split to make 1" pieces.  Steam one.  After steaming KD the steamed piece.  Air dry the mate.  Set in south exposed window in eastern Tn for months of June and July.  Photograph. 

More data.  Period furniture would have been made with air dried lumber.  Even see any reds in it after a century or two?

More data.  Any walnut not colored during finishing will bleach to a light beige after a few years by a sunny window.  I refinished a lacquered walnut conference table that the owner thought was some different wood because it was so light, about like aged ash.  

If the walnut will be stained the color before staining hardly matters.  If not stained, or oiled which creates color,  the reds are fleeting upon exposure to sunlight.  It is for this reason I always stain my walnut pieces with burnt umber mineral pigment stain.  (burnt umber is a redish brown pigment which provides a natural looking color to walnut.  )

Is it the photography or is the one on the right darker and with a greater color gradient?

[Bill Tindall]

Is it the photography or is the one on the right darker and with a greater color gradient?

The one on the right was steamed before kiln drying.  Left is air dried.

[rwe2156]

I've heard that air dried has better color. One reason I stick to kiln dried is because I've always heard it kills the bugs in the wood. I think air dried lumber would have less internal stresses?, maybe. What do you guys think?

Definitely less internal stress.

Beetle infestation is a major issue where I live.

If I get sawmill lumber, I get it freshly sawn and immediately treat with bora care prior to stacking. Be sure to sweep sawdust off boards!

One of these days, I will make a kiln, but for now, if I bring into my bench room which is climate controlled, it will get down to 8% pretty quickly.

That said, I haven't used a moisture meter in 5 years and haven't run into any problems (yet).

[jteneyck]

Definitely less internal stress.

Beetle infestation is a major issue where I live.

If I get sawmill lumber, I get it freshly sawn and immediately treat with bora care prior to stacking.  Be sure to sweep sawdust off boards!

One of these days, I will make a kiln, but for now, if I bring into my bench room which is climate controlled, it will get down to 8% pretty quickly.

That said, I haven't used a moisture meter in 5 years and haven't run into any problems (yet).

That ain't necessarily so.  I've had white oak split and/or honeycomb something awful because it air dried too quickly.  Air drying has the potential for more defects of all kinds compared to kiln drying.  Almost no control vs. almost complete control.  

John

[CStan]

Had more problems with air dried lumber than I ever did with KD stuff. Count me amongst the crowd who was just sure air dried was better in almost every circumstance. Paid a price to find out it wasn't.

[MichaelMouse]

Had more problems with air dried lumber than I ever did with KD stuff.  Count me amongst the crowd who was just sure air dried was better in almost every circumstance.  Paid a price to find out it wasn't.

Obvious you didn't follow good procedure in your air drying.  A few thousand years with no kiln says you can do just fine.  Read the book referenced above and do it right. 

Where space is not a problem stacks of hardwoods are often air-dried outside to ~13% before they enter the kiln, as a money-saving measure. 

It's how it's done that counts. Kilns aren't magic, they just create RH rather than take what's free.