This slurry mixture is poured into a slightly tapered flask and a reusable pattern (i.e. the item used to create the shape of the mold) is used.
Then a torch is used to ignite the mold, which causes most of the volatiles to burn-off and the formation of ceramic microcrazes (microscopic cracks).
These cracks are important, because they allow gases to escape while preventing the metal from flowing through; they also ease thermal expansion and contraction during solidification and shrinkage.
If a metal with a low melting point is cast then the firing can be skipped, because the mold has enough strength in the "green state" (un-fired).
The main disadvantages are: it is only cost effective for small- to medium-sized production runs and the ceramic is not reusable.