So, the first test batch of bricks came out of the kiln, and I immediately set about smashing them. I had tested different proportions of sand and grog and I wanted to find out what was stronger. I realized that grog makes stronger bricks- the ones made with sand were more crumbly and powdery. I think, though, that might be also due to the size of the particles. The sand I used was very fine, whereas the grog was coarser (see below). I also realized that the thicker bricks, like the one above, did not fire evenly all the way through. I have to design my module to be thinner. The mold I tested with a centre block did not work very well because I made the mistake of leaving the block in the clay while it dried, so the clay cracked from the shrinkage. I fired only a piece of the resulting brick- the colour difference is visible in the photo.