Drying eucalyptus in a solar kiln

[leavengs]

A visitor to our Ask the Expert forum posted the question, "What suggestions do you have for drying eucalyptus wood in a solar kiln?"

There really isn't much detailed information on drying any wood species in a solar kiln since you have such limited ability to control temperature and humidity. The most important thing is to closely monitor drying and take the appropriate steps when there is evidence that the wood is drying either too slowly or too rapidly.

If the species of eucalyptus is very dense and prone to warp and checking, high temperatures and rapid airflows (which are possible in a solar kiln) can dry the wood too quickly and result in significant degrade of the lumber. The common approach for 'difficult to dry wood species' is to air dry the lumber for 6 to 9 months. Even with air drying, when it is hot and windy, the wood may begin to warp and check. If so, you could place the wood in a covered location and/or cover it with a shade cloth to slow the drying rate. On the other hand, if the wood begins to mold due to drying too slowly, you need to take steps to speed the drying process (which can be difficult in cool, humid climates).

Once the wood is below about 20% moisture content, you can move it into the solar kiln. As with air drying, you will have to closely monitor the wood - if the wood is warping and checking you need to the slow drying rate. Often the way to do that in a solar kiln is to either open the doors and turn off the fans and/or cover the glass panels with a tarp to lower the temperatures.