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equalizing and conditioning in a DH kiln

Started by Dan_Shade, April 19, 2012, 09:24:02 PM

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Dan_Shade

Any tips?  I have to get a load equalized and conditioned.
Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

beenthere

I'd think that would depend on just where you are at with the load, as far as mc variation (within boards and between boards) and drying stresses in the lumber. Have you been sampling along in the drying schedule?
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Dan_Shade

my sample is at 13%  I haven't tested for tension
Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

scsmith42

Dan,

What species
what thickness
did it go in green or partially dry?
How long has it been in the kiln?
What is the delta between the shell MC% and the core %?
What are your current kiln settings (temp and RH%?).

Typically to condition you can add some water into the kiln (but don't wet the lumber) by spashing several buckets of water on the floor (compressor off) or injecting steam.  It's best if you have an idea of the core and shell MC%'s in advance though.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Dan_Shade

Thanks Scott,

it is white oak

1 1/8" thick

been in the kiln 35 days

How do I determine the delta between the core and shell?

kiln set at 120 degrees and 40% relative humidity

Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

Den Socling

Dan, to get that delta MC, cut a wafer about 1" wide. Bandsaw 1/4" shell off the wafer. Weigh and bake the samples. Easy if you have the set-up. Weighing is difficult if you don't have a digital scale or an old triple beam balance. I use an old toaster oven but you can use a microwave if you're careful.

scsmith42

Dan, in addition to Den's method you can use a moisture meter with insulated pins that are 1/2" long.  Take a reading after you've penetrated about 1/8" into the face of the board (shell), and then another reading when the pin's are fully inserted into the board (core).

At 35 days, unless it is QS you should be in the ballpark.  Depending upon how rapidly you dried it from green, it may be within one to two percentage points between shell and core.

Generally I condition by sterilizing the load at 135 (assuming that I'm within 1% or so delta between core and shell), and then adding 30 - 40 gallons of water into the floor of the kiln, turning the compressor off and letting the temp drop down over a 2 day period, leaving the fans running.  As the kiln cools down, the RH% goes up and the lumber equalizes.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

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