How to Make a Wood Kiln from a Freezer
Wood kilns are used to reduce the moisture content of newly milled wood. The moisture content of wood must be reduced so that the wood fibers are stable and won't change too drastically in density and size. This is especially necessary for wood used in interior construction or for artists' projects, as wood fiber shrinkage or expansion wreaks havoc with fine calculations and joint fittings. Inoperable freezers make excellent wood kilns as they possess a seal which makes them air tight, and minimal drilling produces controllable air flow. They are also inexpensive to acquire and take up relatively little space, are weatherproof and thus may be left outside, and are easily lockable for the security of wood left to dry.
Things You'll Need
- Inoperable upright freezer
- Bucket
- Sponge
- Bleach
- Water
- Rubber gloves
- Drill
- 1/2 inch drill bit
- Three electrical boxes
- Electric water heater thermostat
- Light socket
- Light switch
- UF wire
- Waterproof electrical connectors
- 40-watt incandescent light bulb
- 60-watt incandescent light bulb
- 75-watt incandescent light bulb
- Pin moisture meter
- Wood
Instructions
-
-
1
Purchase a used, broken upright freezer from a local used appliance supplier and use a bucket of half bleach and half water, a sponge and rubber gloves to clean it out, as used appliances are usually not clean enough even to serve a non-food related purpose.
-
2
Place the freezer in the location chosen for drying wood.
-
-
3
Drill four 1/2-inch holes on each side of the freezer at the top, for a total of eight holes. Then open the freezer and drill eight 1/2-inch holes in the bottom of the freezer.
-
4
Mount a waterproof electrical box on the inside of the freezer at the top to house the thermostat, and a box at the inside bottom center of the freezer for the light bulb. Mount one final box on the outside of the freezer for an on/off switch for the inside light.
-
5
Follow manufacturer's wiring instructions to wire an electric water heater thermostat into the top inside box and a light socket into the bottom box. Then attach a hooded light fixture to the bottom inside socket to prevent water from dripping on the light bulb, and screw a 40 watt incandescent bulb into the socket. Finally, install a light switch into the outside box and wire it to the inside light socket. For all electrical work, use UF wire and waterproof connectors to prevent water shed from the drying wood to damage the kiln's electrical system.
-
6
Replace the interior freezer racks.
-
7
Paint the wood's end cuts with green wood sealer. Place the wood inside the freezer kiln on the freezer racks and close the door.
-
8
Turn the kiln on by turning on the interior 40-watt bulb. Leave the wood sealed inside the kiln with the light on for one week, then periodically open the kiln and check the interior moisture level with a pin moisture meter until the moisture level decreases to between 14 and 16 percent.
-
9
Change the bulb to a 60-watt incandescent bulb and let the kiln run until the moisture level decreases to below 12 percent, then change the bulb again to a 75-watt incandescent bulb. Let the kiln continue to run until the moisture level inside the kiln is between 6 and 8 percent. Turn the kiln off and let the interior cool for three days to one week until the wood is completely cool.
-
1
Tips & Warnings
The freezer wood kiln is suitable for indoor or outdoor use, thus either location is permissible.
If leaving the kiln outside, fit the freezer with a pad or combination lock to secure the contents.
References
Resources
- Photo Credit wood image by Jakub Niezabitowski from Fotolia.com
