According to the Merriam-Webster Dictionary, the definition of raku
: Japanese hand-modeled pottery that is fired at a low temperature and rapidly cooled
: a process by which pottery is fired at a relatively low temperature and then moved while hot to a closed container with combustible materials (such as paper or sawdust) that ignite and cause a reaction creating colors and patterns in the pottery's surface
also : pottery produced using this process
From my perspective, Raku is an extremely fun way to fire your clay that creates unique outcome that is never the same twice. I built my own Raku Kiln out of a 55 gallon drum using parts from Amazon.com and a little elbow grease. With a single BBQ (25 pound propane) tank and a weed burner, you can reach 1010 Celsius in under an hour. Here are the high-level steps to build you own...
This was a really easy build and cost me about $250 total. The parts are few and easy to get. You need a barrel ($10), 2 inch thick Ceramic Fiber ($95), a Pyrometer ($60), and a weed killing Propane Torch ($60).
You basically cut the top off of the barrel so that you have about a 26 inch bottom and a separate top. Next you cut a 5 inch square in the top of the barrel and another in the side about 3-4 inches up from the bottom.
You then need to line the bottom and sides with the Ceramic Fiber. You do the exact same thing with the top.
Drill a 1/2 inch hole in the side of the barrel about halfway up for the Pyrometer and put it in the side. I added handles to the lid and the bottom to make transport easier.
Hopefully this helps you save some money and have fun. Raku is pretty awesome! If you have any questions please feel free to ask.
Build at your own risk and only if you feel you are competent for this type of activity - Make sure to wear safety gear and take your time while building and using your kiln. You are dealing with really hot temperatures in very close proximity to your body. Leather apron, heat resistant gloves and long tongs are required. Please be careful if you decide to build and use one yourself.
I would highly recommend trying out this exciting form of pottery firing and the instant results you get.