to have formaldehyde issues from time
QWe bought some lumber and it is a bit too high in MC, probably because it
was stored incorrectly.
How do we lower the MC safely?
ARedrying lumber that has been kept in uncontrolled storage requires great care if the species being dried is
prone to surface checking.
The risk is that surface checks that
were tightly closed may become permanently opened or internal hairline
checks can occur.
This is a risk with oak, chestnut and
a few other hardwoods, but not pine,
poplar and maple.
The lumber must be stickered for
Do not use steam spray or water
spray during kiln warm-up.
Two temperature steps are suggested for the redrying operation. The
first step should be about one day long
at 130F or 140F.
When the kiln temperature is
reached, set the wet-bulb controller
to achieve an EMC that is numerically
halfway between the current MC of the
lumber and the MC desired.
It may be necessary to close the
vents and add moisture at this time
to achieve and maintain the correct
The second step should be at the
final temperature of the drying phase
of the basic schedule for the species
being dried…usually 160F.
WOOD DOCTOR’S Rx
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