Attempted to make some refractory bricks today. Refractory bricks are bricks that reflect the heat back into a fire instead of absorbing it. This makes the fire hotter, burning up more harmful pollutants and not wasting energy that can be used to cook with instead of heat stone. I’m attempting to make these for use in a rocket stove. I didn’t make my bricks the way they made them in that video, but was just working with what I had laying around the house.
Where we live in East Austin there’s a lot of clay in the soil. About a two weeks ago I cleared the topsoil off a spot in my backyard and then dug out a couple shovels full of dirt. I put the dirt in a 5 gallon bucket and added a lot of water. I stirred it up pretty good to help any larger pieces dissolve, it could take some large pieces of clay awhile to really dissolve. After everything but rocks and debris seemed to be dissolved I strained it through a window screen into another bucket. I let it settle a few minutes and then poured off the brown water containing all the clay into another bucket and left the sand behind. Next I just let the bucket sit a couple days and let the clay (and hopefully not to much silt) settle to the bottom. The clay will settle to the bottom and leave a pretty clear upper layer of water… I just carefully poured this off. I suppose I could have even siphoned it off as well. I just let this sit out and after awhile most of the water evaporated away. Then I dried it out completely on the concrete in the sun.
So now I have dried clay. I mixed that really well with the perlite and then added water. Now mix mix mix.
1.5 parts dried clay
5 parts perlite
1 part water
There was enough clay in the mix to really hold all the perlite together pretty well. I made a form out of wood. Got the form wet so that the bricks could slide out. Filled the form about half way up with my wet refractory brick mix and then pressed it down with another piece of wood that fits snuggly into the top of my form. I made three bricks in all. Now I’ll let them dry in the sun a few days and then built a nice fire around them to see if I can fire them. Hopefully they don’t just crumble apart. If it works I’ll make some more of them and then use them to build a nice rocket stove.
