A kiln is a large oven or furnace used to bake pottery in or to dry out grain for example. Using a dehumidifier, the average craftsman can easily make his own. By enclosing the area under a wall-mounted workbench and installing small dehumidifier to it, you can dry several weeks’ worth of turning. This type of kiln is informally called a coffin kiln. You can also build a free standing box, depending on the type of lid you want. If installed under a bench your lid can drop down. In the case of a free-standing coffin kiln you can use a lid which opens like that of a coffin.
To build a free-standing kiln you can merely build a box with wood and if you install it under a bench, just enclose it completely with slabs of wood. The voids in your construction should all be filled with foam insulation. You can use spray foam insulation to keep the enclosure completely air-tight. Make a free standing frame and mount a good quality bathroom ventilation fan into it. Install this at one end leaving about 10 inches behind it to allow circulated air do be drawn from behind and hot air to be blown through the remainder of the coffin. In that 10 inch void mount an outdoor light socket, one that can stand up to moisture. Cut a hole in a metal coffee c and install that around the bulb. Now for the dehumidifier.
Put a switch outside the box to turn the light on and off. The light bulb is the heat source and the can the amplifier for the bulb’s heat. At the other end of the box install a high quality room dehumidifier. A dehumidifier can be bought any good appliance store or you can find one on the internet. Make sure you buy one that has a drainage option and drill a hole for the hose to fit through. Put the hose inside an empty bucket. This bucket will need to be emptied daily.