For Those Who Would Like to Dry Wood

[TomFromStLouis]

This is such a good solution for the operation that mills its own wood for a one or even two man shop. Very nicely done!

Start selling any of the wood and you will be scaling up everywhere in a hurry. 

I sell wood so I am running two entry level Nyle DH kilns in insulated boxes off reefer trucks, loaded with a fudge lift. I too only put in air dry stuff starting around 16%. I think drying that last ten percent will always be a bit of a bottleneck in an operation going from A to Z. but you'd be making huge projects if you ever need more than 400' every two weeks. 

He's doing it right folks.

[tomsteve]

I wrote the title of this post with the intent of showing that it's not hard to dry your own lumber, 

  

John

i looked into building one about 20 years ago. read some great info on it and one piece i recall:

its easy and safe to take too long to dry a load of lumber. even easier to go too quick and destroy a load of lumber

[jteneyck]

i looked into building one about 20 years ago. read some great info on it and one piece i recall:

its easy and safe to take too long to dry a load of lumber. even easier to go too quick and destroy a load of lumber

Very true, Tom.  However, for most species the faster you can dry it w/o causing damage the better.  Maple, for example, will have whiter color if you dry it as fast as possible.  And it is possible to ruin lumber by drying too slowly.  If the RH stays too high for too long mold will start to grow and ruin the wood.  I had that happen with a stack of maple I cut really late in the year and then wrapped with landscape fabric to keep the rain and snow out of.  Big mistake.  

That experience showed me that air drying is not as foolproof as one might think.  According to Dr. Wengertt (sp) you will get higher degrade air drying than kiln drying. I would say that's true even with careful site location, but despite that risk I still choose to first at least partially air dry lumber in order to run more lumber through the kiln per unit time.  And with the dehumidification kiln, as Ian pointed out, condensate from green lumber can cause corrosion and failure of household dehumidifiers, so that's another consideration.  

I've been milling for cash for a few customers this Spring.  It is amazing how casual and careless most have been about how to dry the lumber despite my recommendations.   If you plan to have any lumber milled, or plan to buy green lumber, take the time to set up a well constructed base, preferably in the shade (can't emphasize that point enough), sticker the layers every 18" and put a waterproof roof on top.   

John

[jteneyck]

To bring this to a conclusion, the load of 8/4 white oak and hard maple dried from 19% to 7% moisture in 25 days. That's a rate of 0.47%/day.  In comparison, my solar drier has a load of 4/4 ash in it.  In the past 17 days it has lost an average of 0.41%.  The dehumidification kiln is the clear winner; it just costs a little money to run.  

John