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View Spikes's profile

wood air drying estimates

by Spikes
posted 09-30-2018 04:41 PM


5 replies so far

View Gene Howe's profile

Gene Howe

11906 posts in 3989 days


#1 posted 09-30-2018 05:04 PM

My experience with green Doug fir is that you’ll need proper stickering, lots of weight to help prevent warps and twists and, sealed ends. I’m in AZ and, I’d recommend 90 days minimum for 1” thick soft wood. A fan to circulate the air…just a small table fan or, a cheap box fan is good. Keep checking the MC about every 30 days.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View HerbC's profile

HerbC

1801 posts in 3420 days


#2 posted 09-30-2018 05:16 PM

First of all, the “one year per inch of thickness” drying “rule” is a rather inaccurate generalization. Most green lumber will air dry much quicker than that.

In most climates, air dried lumber will not reach 7% when dried outside. Generally it will stabilize somewhere in the mid to low teens.

Once the air dried lumber has stopped “drying” outside you can often dry it further by moving into a conditioned space where the ambient relative humidity is lower than the outdoor RH and leaving it inside to drop more moisture.

Proper stacking (including the use of adequate number and sized stickers) is critical to producing useable quality lumber. Good airflow through the stacked lumber is also usually important (but some species don’t do well if dried too fast, white oak being one example.)

Good Luck!

Herb

-- Herb, Florida - Here's why I close most messages with "Be Careful!" http://lumberjocks.com/HerbC/blog/17090

View Aj2's profile

Aj2

2562 posts in 2359 days


#3 posted 09-30-2018 05:29 PM

I think you should stay away from air dried Dfir. If the pitch isn’t set well in a kiln you see it weeping if the temp get up enough. There might be some projects to use it on I just think of any right now.
If your out here on the west coast like look for Ash, oak or Alder yes I said alder.
Try some air drying see what happens doing is learning.
I’ve experimented with lots of woods some were complete failures some not. But I still gained knowledge

-- Aj

View KuhShise's profile

KuhShise

12 posts in 492 days


#4 posted 10-01-2018 12:47 AM

Like most others on this page, we are in various places on the learning curve. Most of my experience has been without the benefit of a moisture meter until recently. As my profile references, the past 8 years have been spent (mostly) working with White Pine paneling. I have done some other projects using Cherry, Birch Maple, Red Oak, Spruce, Catalpa and Hemlock; mostly on specialty items. Recently I sprung for a pretty good moisture meter and have been surprised by the readings on some things I thought were quite dry. Initially I followed the recommendations of my local saw mill operator concerning the need for kiln drying and acclimating of paneling prior to final finishing and hanging in the house. I thought that the lumber I was processing in my shop was in the 8% range, but the new meter has shown the pine in the shop is closer to 10%. Despite the fact that the heat is from a separated combustion gas ceiling heater. (Closed loop combustion with the outside combustion air being blown into the unit and all burned gas and moisture exhausted to the outdoors.) The house has a geothermal heating system with basement heated using in-floor heat in combination with continuous circulation warm air for the living spaces. Acclimating the paneling for a couple of weeks in the heated basement brings the moisture content down to about 8.5% and the paneling that has already been installed over OSB on the walls is about the same percentage. Recently we were gifted a truck load (700 bd.ft.) of Black Walnut that has been barn stored, stickered for over 50 years. I was surprised when this came up at about 11% on the meter. We stickered this on 4×4’s in the shop and in the intervening month or so it has dropped to about 9.5% and seems not to have changed in several weeks. We have had a wet summer, so some of this higher than expected moisture content may be due to outdoor dew points. It will be interesting to see what the measurements change to after Winter sets in and 20 below dew points are encountered on a regular basis.

View KuhShise's profile

KuhShise

12 posts in 492 days


#5 posted 10-01-2018 02:44 AM

Spikes, You and others might find this table on relative humidity vs wood moisture equilibrium percentages helpful. https://www.extension.purdue.edu/extmedia/FNR/FNR_403_W.pdf

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