Raku kilns are rather fun because they can be made out of recycled materials. All sorts of designs will heat to around 1000 degrees Centigrade, and it is possible to fine tune a design, like the one that I have illustrated, to get up to 1100 degrees or so by better insulation and increasing the height of the chimney. In fact it is a really good idea to try out modifications of your own, and to find out what works and what doesn't. This design is very similar to that of the first kiln I made that is shown in the photo below.
Some copper red jugs
I made a useful discovery the other day, after a careful test of one pot, that a whole batch of copper red pots that were under fired in my last wood firing, could be transformed by firing them in the electric kiln! The pots had been an unpleasant sugary heavy liverish red, and really benefited from the oxidized refiring. All sorts of lovely shades of red, purple, blue, green were achieved.