I want to make a small rocket stove. I 'd like to make my own fire bricks but I'm not 100% sure what to make it out of.

I see that vermiculite and perlite are very good insulators. I think bentonite clay can be use as well but I'm not sure. I'm thinking along the lines of cat litter (bentonite) and then mix in vermiculite or perlite and make then in molds to form bricks.....


Any one else got any idea's on this?

Peter

You need high fire materials, and high build high fired grog (broken high fire materials) to build good fire bricks. Kaolin clay, broken porcelain, possibly some zircon flour. Vermiculite is a clay that melts at a low temperature and perlite is glass, so they will both form voids in the brick when the brick is fired (which may or may not be desirable).

You will also need a means of firing this material to a suitable temperature. If you are using a pottery kiln, cone 10 or higher.

http://www.bigceramicstore.com/information/ConeChart.html

There is plenty of material available on various pottery websites that you can find the gaps in this information readily.

Phil

I use Castolite. There are many brands of castable refractory. Check in local yellow pages.

A rocket stove is for cooking meals on, temps shouldn't get to high for perlite/clay mix. not like you will be forging in a food oven.
Best thing to do is just try. lots of local materials available for woodstove range fires. Try some local clay, it;'s typically free or cheap. and often locals used what they had on hand, even if they had to repair rebuild often as it was cheap.

What is your max service temp? The problem with homemade ceramics is firing them properly. Bricks aren't expensive, and when you figure in the costs of raw materials, labor, energy for firing, and experimental failures, DIY probably isn't saving you anything in the long run.

there is a site called permies .com try on it they have rocket stove design and materials used ,and research from third world countries

I was just at a pottery store over the weekend, got some koawool for 2$ a sq ft (score) and three in some used bricks for free. The guy was very knowledgeable about castable refractory he uses fire clay sand and Portland cement, he said bentonite is really just a binder and makes the mix more plastic, not necessary fir heat resistance. The perlite is actually a volcanic material and could be a good filler.

Look for wood fired clay at a pottery store, I believe it is rated for cone 14 firings.