I've made a few hundred bricks now, which has allowed me to develop a fairly successful molding process, but has also allowed me to see the potential improvements to First Mold.
Sand, as a release agent, is essential, both on the mold and on the clay. I've found that the mold works best when it has been 'seasoned' with a few bricks- the first few of each molding session are more likely to stick.
I regret not making a bottom profile, because I have to fill the mold with a lot more clay than is necessary. I have to pack it well, making sure to push my fingers into the corners.
I scrape off the excess clay. A simple piece of plywood works well, and follows the profile of the mold nicely.
Because the clay sieve I use still allows small pieces of flint to remain in the mixture, the plywood can drag the flint across the surface. When this happens, which is most of the time, I smooth it over with water.
To release the clay, I have to whack the mold a few times. Since this picture …
Radzymin and Marki were two towns which were major brick-producing areas for Warsaw. They are very close together, along the same major road heading northeast out of the city; I passed them both on my quest for brickyards.
An unusual one at the H.G. Matthews factory. Jubilee bricks?
There are a lot of things that aren't working with this brick operation (more on that later), but one thing that is working is the sand on which the bricks rest. Since they have a profiled underside, they need to be supported during the first stage of drying to prevent collapse. I was afraid I would have to mill out lengths of wooden or styrofoam profiles, but then I received the suggestion of a simple sand rake, which is a much more resource-efficient method, as well as allowing me to dry as many more bricks at the same time.