Why does the material seem to mix so thick in the beginning, then gradually thinning out over time?
This is by design. We do not want too much water in the flask after curing because it would make the mold weak when it comes time to cast after burnout. This is specially true if the castings are done on a centrifugal casting machine. Because of this unique requirement, different batches or material even within the same batch might appear to behave slightly differently during the mixing start. The best thing is to keep about 1 to 2 % extra water and add it if necessary.
