Creating a homemade wood stove can be very difficult, but if you are careful and diligent in your work, it can be done. You should have some professional knowledge on fire and welding before starting to make sure that you do this safely and test it outside before ever allowing it into a house.
Find an Electric Water Heater
The first thing you will want to do is find an electric water heater that is free of corrosion and rust damage. The heater should have a 30-50 gallon capacity. After finding the water heater, lay it on its side and weld on legs to keep the stove off the ground.
Cut The Top of the Heater
After the legs are attached to the heater, cut off a portion near the top of the stove, and then weld the piece back on upside down. Cut air holes in this upside-down portion so that the air can go into the air channel, which will force the air and fire to go down through the rest of the stove and spread the heat around.
Cut another hole in the bottom back of the stove to allow air to exit through a pipe that will take the smoke outside of your house.
Build a Grill
If you want to be able to cook on the woodstove, cut strips into the upside portion that you welded back onto the stove to create a grill.