Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne 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



Click here to return to the General Topics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory