Wood drying kilns can range in size and complexity from simple backyard solar sheds to high-tech facilities within industrial lumber processing warehouses. For most personal woodworking or home improvement projects, a wood dry kiln heated by solar energy will provide all of the necessary capacity with minimal expense and hassle. Building and operating your own small wood dry kiln can be a fun and rewarding project that should repay your effort with years of affordable, high-quality lumber dried to perfection.
Instructions
Framing Your Kiln
1. Using typical construction framing, build the framework for your kiln, which will be a small wood building approximately 7-feet tall, 5-feet wide and 8-feet long. A kiln this size will let you dry a little more than 550 linear feet of lumber at a time. The front of the kiln will include a slope of clear, corrugated polycarbonate that runs from the top of the back wall to a 2-foot front wall. Use 2-by-4 studs to frame the walls and 2-by-6 lumber for the floor.
2. Frame in openings for two or three vent fans (depending on their size) in the back wall, and for one or more doors in a side or back wall.
3. Use 2-by-4 studs to put together support frames for two or three window fans. The frames should attach to the sloping wall frame from the underside and hold the fans in place about 18 inches from the back wall and 3 feet from the floor.
Covering Your Frame
4. Fill the gaps in the wall and floor frames with insulation, but leave the sloping part of the front wall open.
5. Lay plastic sheeting over the floor frame and insulation, and staple it down.
6. Nail plywood onto the floor and wall frames (both sides), again skipping the sloping part of the front wall.
7. Nail polycarbonate to the sloping part of the wall frame to create the "greenhouse window" that will provide the solar heat for your kiln.
Finishing Your Kiln
8. Paint the inside walls and floor with a rubberized sealant to help lock out moisture and absorb heat energy from sunlight.
9. Paint the outside walls with a pale, weather-resistant paint.
10. Set your door(s), wall vents and fans into their frames and secure them in place.
