Re: What is the composition of CERAMIC SHELL
Hi as has already been said 'ceramic shel' investment is a slurry of primarily coloidal silica in water, added to that a binder and often wetting agents, and ocasionaly a dye indicator so you can tell its dry, and then the rest is stucco usualy mollochite or zirconia grit.
how ever this process is very new haveing been developed in the 2nd world war for i belive casing jet engine components.
so it was not what cilleni used!,
lost wax casting has been around for at least 4000years,
and molds have been made out of all manner of things usualy mixtures of clay, sand , cow dung, broken potts. The chineses were lucky enough to have a natuarlly ocoring clay wich could be used direct with no other materials added,
the requiments of the mold is a materail that can be molded round the wax, can take the heat and the theramal shock .
for the last few hundred years in europe this has been plaster mixed with grog (ground up fired clay)
im not sur when it was first used but now days people useing plaster investment simply mix in silica sand (wich is what beaches are made from)