Setting up an indoor wood stove for outdoor use is the easiest way to create a homemade outdoor fire-burning heater. You can remove the door because errant sparks and smoke aren't the problem outside as they are indoors. Another alteration involved the wood stove's ventilation. Rather than a long flue that runs up through a chimney and exits through the roof, an outdoor wood stove only need enough piping to divert the smoke away from your home or outdoor seating area. A single pipe that is several feet high with an open top should be sufficient.
An outdoor wood stove might not be prepared to handle the elements if you started with an indoor wood stove. A coat of heat-resistant paint or lacquer will help protect the metal stove from rust. You might also choose to build a stone or brick housing for the stove to integrate it into your patio or deck. A flue cap and removable door cover will be necessary if the stove is in an uncovered area where rain and snow can enter the stove.
Wood-burning furnaces are another type of outdoor wood stove. They are freestanding structures that include a fire box as well as a pump mechanism for circulating a liquid solution throughout your home. A wood fire in the furnace heats the liquid as it passes through the housing, then pumps it into your home where it releases its heat. Indoor wood stoves, which are typically designed to heat only a few rooms and require new wood fuel every few hours, are not large enough to turn into furnaces that will heat your entire home for an extended period. Instead they are more appropriate for turning into outdoor stoves that only need to warm a patio or deck seating area.
An outdoor wood stove made from an indoor stove offers several key benefits. Stoves that leak smoke or are damaged might not be safe or attractive for indoor use, but provide perfectly functional stoves outside. It's also a form of recycling that keeps the old indoor wood stove out of a dump or scrap yard. Burning wood is inexpensive if the fuel is abundant in your region, and might be more convenient that keeping a supply of propane on hand for outdoor heaters.