wax melting temperatures

[Alison]

Does anyone out there have or know of a basic chart/guide to melting temperatures of different kinds of wax? I have basic firsthand knowledge, but was hoping to have something specific as a guide to help me with some wax castings I am making. Thanks.

[jwebb]

There are many variables in any given wax. Some of its constituents melt at a lower temp than others, (as is also true in metals). And there are also many differences between waxes. The Manufacturers measure a "congealing point" which is the temp at which a wax changes from a liquid to a semi solid state when hardening; a "softening point", which is the temp at which a wax goes from a solid to a semi-solid state when melting (and those two are not exactly the same); and a "Drop Melt Point" which is the temp at which a wax fully transitions from a solid to a liquid. In general, those 3 temps range from lower to higher in the order stated. It can get very complicated. The thermal expansion of various waxes is also important. In castings, different waxes are often used for the gating and sprues than for the "pattern" or sculpture itself. The idea is, when melting out the wax, you want the gates and risers to melt and flow out first, then the pattern, so that you don't get a contained thermal expansion that can crack the shell. General temp ranges I've seen are from about 135 to 165 F. In my own work though, I confess I've mixed 'em all depending on what looks right to me, without regard to all the science.