We have initially chosen Redart Fireclay as the standard clay for this project. We received dry clay samples from two brick manufacturers in California, and tested them for plasticity, grog content, water requirement, and firing temperature. The brick manufacturers’ clays are proprietary, but Redart, made by Resco Products of Pennsylvania, was the best commericially available surrogate we could find.
For the brick mixes we tested, the total sand and grog was about 50 percent by dry weight. Therefore, our initial mix is
50 percent dry Redart Fireclay
50 percent 12 mesh glass
16 percent water by dry weight of clay plus glass seemed to create a pressable mix. One-inch thick solid bricks are desired. The formula for one brick is:
800 grams 12 mesh glass
800 grams dry Redart Fireclay
256 grams room temperature water
Here’s the procedure:
Weigh 800 grams of 12 mesh glass into a mixing bowl
Add 800 grams dry redart Fireclay
Blend the dry materials together, then add 256 grams of water and mix by hand
Form the wet glass into a loaf, and place it into a wooden mold