DIY Electric Wood-Drying Kiln

Making wooden bowls is simplified with a wood-drying kiln.

Wood-drying kilns are for people who turn a lot of projects on a wood lathe. After partially turning a green piece of wood, placing the project in a kiln speeds up the drying process so the finishing part of the work can be done. Hobby-sized wood-drying kilns increase the productivity of a woodworker and can be built with simple household items.

Things You'll Need

• Wooden cabinet, 36" wide, 12" deep, 18" tall
• Jigsaw with wooden blade
• Glossy paint
• Paintbrush
• Power screwdriver
• 6-inch fan pre-mounted in square housing
• 2-inch screws
• Power drill
• 1/2-inch drill bit
• 3/4-inch screws
• Surface mount electrical junction box
• Surface mount electrical two-switch box
• Wire cutters
• 14-gauge 3-conductor non-metallic sheathed electrical wire
• Wire staples
• Electrical extension cord, 12 to 15 feet long
• Wire strippers
• Electrical tape
• Wire nuts
• 1 junction box cover
• Felt tipped marker
• 2 single-pole electrical switches
• 1 double-switch cover
• Ceramic light fixture for heat
• 60-watt light bulb

Instructions

1. Cut a hole that is approximately six inches in diameter on one side of the cabinet with a jigsaw. Position the hole on the upper third of one side of the cabinet and facing so that there is plenty of room for exhaust -- this will be where the exhaust fan will be mounted. Cut the hole so that the fan blades will be unobstructed, but there is still enough room to mount the fan.

2. Paint the cabinet inside and out with two coats of glossy paint, allowing the first layer to dry completely before adding the next. The paint will provide a moisture barrier for the cabinet and its contents.

3. Attach the exhaust fan to the inside of the hole, using 2-inch screws (or included screws, if applicable). Drill a 1/2-inch hole nearby to run electrical wire to the fan. Select a location for the ceramic light fixture on the bottom of the cabinet, opposite the fan. Drill a 1/2-inch hole near this location for the fixture wiring. Surface-mount the junction box on the fan side of the cabinet with 3/4-inch screws, near the back. Mount the switch box nearby closer to the front in a similar fashion. The exact location doesn't matter, so long as both are easily accessible.

4. Cut a piece of electrical wire with the wire cutters to run from the switch box to the fan and another to run under the cabinet and up through the hole in the bottom to the light. Oversize these wires by 24 inches to give yourself some room to work. Starting at the switch box, poke the ends of the two wires through one of the punch-out holes on each side, pull about 12 inches through and affix the wire near the switch box using wire staples. Run each wire to the component it belongs to, along the outside of the cabinet, affixing it with staples every six inches.

5. Cut the end off of the extension cord with the wire cutters and expose the wire inside. Strip about 3 inches of insulation off the wires and insert through the bottom of the junction box. Use a wire collar if the box is metal. Cut two pieces of electrical wire long enough to reach the switch box plus an extra 12 inches. Inside the junction box, use wire nuts to splice the ends of these two electrical wires to the extension cord end. Wrap each splice with electrical tape until all expose wire is covered. Close the junction box by screwing on the junction box cover. Attach the electrical wires to the cabinet with wire staples and label each with a felt-tipped marker (ie. "Fan" and "Heat"). Push each wire through the appropriate punch-out on the sides of the switch box.

6. Install the first switch by wiring the wire from the junction box to one set of poles and the wire to the element on the other set of poles. Wire the wires according to package directions. Do not forget to wire the bare ground wire to the green grounding pole! Screw the switch into the appropriate side of the electrical switch box. Repeat with the other element's switch and install the switch cover.

7. Wire the fan wire to the fan, according to the package instructions. Wire the light socket and attach the base to the cabinet with included screws. Screw the light bulb in to the socket. Test your wiring connections by plugging the end of the extension cord into the nearest outlet and flipping the switches. Be sure to label which switch is which.

Tips & Warnings

• Always be careful when working with electricity! Ground connections are safety items and should not be overlooked.

References

• "Irish Woodturners Guild Journal": A Simple Kiln
• Woodturning Online; Building a Bowl Kiln; Dennis Daudelin
• Wooden Crates: Chapter 3 Dry Kiln Auxiliary Equipment
• "Woodturning Magazine"; Small Scale Drying; Alan Holtham