View Full Version : Lumber drying

Dale Stillman
03-04-2003, 12:38 PM
Approx. Sept. 2001 I had some newly cut trees (Fir, Ceder, Alder) cut into lumber. Stacked all w/stickler boards. This summer the moisture content was down to 8%. We have kept it covered at all times. Went to use some Alder the other day & the moisture content is now @ 16%. Is this due to the time of the year in the Northwest? I am making pedistals for a dinning room table w/this. Laminating pieces so that I can get 4-1/2" sq. blanks prior to turning. Will I have problems w/movement? TIA for the help.

Randy Miller
03-04-2003, 1:00 PM
Two things: You didn't mention what size the rough lumber is - I'll assume it's no thicker than 4/4 since your ready to use it. If it is greater than 4/4 then it probably has not dried out yet.

Second, have you left the lumber outside all this time - did you have a really dry summer and a really wet winter? If so, I would bring it inside for 2 - 4 weeks and let it equalize. Make several checks to ensure you're getting good readings.

Keith Outten
03-06-2003, 9:29 PM

I suspect that what happened is that the internal moisture in the boards is propagating to the outside surface of the lumber. I have an EBAC dehumidifiaction kiln and it works on the premise that when you remove the moisture from the air around the load the lumber stack will give up its moisture. This is a continous cycle thoughout the drying schedule as the moisture moves from the center of each board to the outside surface and is removed by the unit.

When air drying lumber, the rate of moisture loss is not constant, it varies with the temperature and relative humidity in the air. The external surface of the lumber will in fact appear to be dry at times, a false indication of the overall moisture content of the board. This is one of the reasons it takes so long to air dry lumber--you cannot control the temperature and humidity.

Reducing moisture content to levels below 12% is almost impossible in Virginia as the humidity is almost always very high.