I just built a mini version of a VA tech solar kiln (4’ x 2.5’ by 2.5’ ). I did it completely out of scrap material! I only had to buy screws and two small fans! I am “turning it on” tomorrow. I gather 2 to 4 feet long local logs from neighbors and arborists and make bowls, boxes, vases, puzzles, pepper mills, and whatever looks interesting. I work with many local woods.

Three questions at this point:
1. Since this is a small kiln with a roof angle of 33 degrees (I live in North Texas) – it is a good idea to tilt it 10 or 15 degrees back in May June, July and 10 or 15 degrees forward in Nov, Dec, Jan? Is it worth putting the kiln on a large lazy susan to track the sun? I realize that this would not work for a full size kiln, but mine is small/light enough that I think I can figure it out, but is it worth it?

2. I want to dry fairly thick wood blanks. Like 3” x 3” x 7” for pepper mills, 4”x4”x12” for turning projects and 7”x5”x4” for boxes (I use the bark edge as the top, these can’t be made from store bought 4/4 lumber). I don’t care how warped or cracked the get during the drying process – I will joint/plane them into rectangular blocks and cracks get enhanced with colored epoxy later. But they must be dry all the way through (or they warp when they are worked). Any advice on drying thick, but small, blocks of wood? I will be mixing these thick blanks with 4/4 boards – any issues with mixing different thickness woods in a mini kiln? Any issues with mixing different types of wood in a mini kiln (beside the issues with mulberry, osage orange and black locust mentioned in another post). I use pecan, walnut, mesquite, lace bark elm, ash, hackberry, bradford pear, chinaberry, post oak, cottonwood and sycamore. Note: I turn all my bowls green and will not be using the kiln to dry bowls.

3. Any other issues I may run into with a mini kiln?

Thanks in advance for any advice.

You'll need a super slow cycle at the beginning. A solar kiln in Texas in the summer can make a lot of firewood out of thick stock in a couple of days. Osage will need to take at least 4 times longer than ash. So mixing species will definitely be an issue. I would definitely not cut the blanks to length and put them in the kiln. With more end grain exposure your degrade will certainly go up.

Do not worry about the roof angle. Thirty degrees or whatever you have is fine.

Consult DRYING HARDWOOD LUMBER to learn more about drying. As the kiln was designed for 1” oak, drying thicker stock of hardwoods will likely require slowing it down by covering part of the collector.

Thanks for the advice. Update: I put about 80 board feet of a mix of 4/4, 6/4, 8/4 and 16/4 mesquite, walnut, lace bark elm, bradford pear and pecan. It works!!! Drying speeds vary greatly. The bradford pear and lace bark elm are the fastest followed by pecan and walnut. Mesquite is the slowest. Almost no cracking so far, bradford pear warps alot and lace bark elm warps a little, all others are fine. Mixing woods and thicknesses seems to be OK (at least so far). Every two weeks I go through it to pull out dry wood. I am weighing every piece rather than relying on a moisture meter. I don't trust mm especially on 4" thick wood. 4/4 and 6/4 are mostly dry. I expect the 16/4 to take 10-14 weeks to fully dry. The kiln opens up a great source for what is effectively "free" local wood for my craft business. And I can dry really thick wood for crafts. This website was key in helping me build a successful mini kiln, Thanks!! I'll update again in a few months. In the mean time I need to find some more logs....