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Cypress Wood Processing
Name: Bill R.
Status: educator
Age: 50s
Location: N/A
Country: N/A
Date: 4/9/2003
Question:
I will receive several cypress slabs, used for clocks
and other decorative items , in a few months. The person holding the
slabs for me would like to start drying them out what is the best method
of storage and starting the drying process for these slabs? The slabs are
about two inches thick and a few have large holes in the middle and will
be very good for projects due to their distinctive shape. The slabs are
of medium size with nothing larger than 20 inches in width but due to the
holes mat not dry out at an even rate and I would like to prevent
cracking and splitting as much as possible. Thank you for your time in
this matter.
Replies:
Seal the ends with a wood sealer ...if you do not have a commercial sealer
you can use latex paint or wood glue. Then stack the lumber on stickers
(strips of hard wood that are about an inch wide and as long as the slabs
are wide. The stickers must be place over each other making sure to place
one even with each end of the slabs to help prevent splitting. Some other
lumber can be placed on the top of the pile for added weight to the top
boards in the stack. Unfortunately, there will be some checking no matter
what you do. Good luck!
Peter Faletra
Bill, One can air dry wood, but it takes patience. The general rule of thumb
is one year per inch of thickness. The wood should be off of the ground, and
"stickered". Stickering means layering the wood with one inch thick spacers
between layers to allow air circulation. Each layer of stickers should be
directly on top of the previous layer to prevent warping. Cover the pile with
a tarp, and weights such as cinder blocks to prevent warping. The sides do
not need to be covered if stored outside. The ends of the slabs should be
painted with a latex-based paint to retard faster drying at the ends, which
leads to cracks.
A word of caution: kiln drying kills insects in the wood, while air drying
doesn't. I have a bunch of air dried oak and walnut, and recently discovered
that it was infected with powder post beetles. These tiny beetle and their
larvae can lead to serious infestations of neighboring wood. Treatment
consist of spraying with a product such as "Boracare" (do a google search for
suppliers). It may also be possible to locate a small mill that will kiln dry
your wood at a reasonable price.
For more info, do a search on Google in the rec.woodworking group and you
will find lots of discussion about drying wood.
Paul Mahoney, PhD
I am afraid there is no easy answer to this question because the drying
process is governed by the initial moisture content of the wood. Then,
for commercial lumber, the temperature, humidity, and airflow around the
wood is carefully controlled and adjusted as the wood dries. Fortunately,
softwoods like cypress are less sensitive to drying conditions than many
hardwoods.
That said, the recommended temperatures for drying cypress range from 120
degrees F for very wet lumber (40% moisture content) to 150 degrees for
the final drying stage, leaving a moisture content of around 8%. For the
details, please visit the USDA Forestry Service's Forestry Products
Laboratory web site at www.fpl.fs.fed.us. Check out Chapter 7 of the "Dry
Kiln Operator's Manual" on their publications page. Unfortunately, this
type of control may be very difficult for a hobbyist to maintain.
For special, high-value wood, sometimes weights or straps are applied to
the lumber to prevent significant warpage. This might work in the case of
your knotty wood. Typical pressures are in the range of 150 pounds per
square foot.
Andy Johnson
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