Although normally considered lightly by those individuals unfamiliar with the process, the dewaxing of the ceramic shell is a critical stage to the investment casting process. The problem is that the ceramic coating on the wax pattern does not expand when heated but the contained wax does thus yielding stresses on the coating that will easily break the green ceramic shell. To circumvent this problem, the shell must be dewaxed very quickly. It must be heated so fast that the wax immediately adjacent to the ceramic shell is liquefied and begins to move before the bulk of the wax even knows that it is warm. This requires a massive dose of heat to the outside of the shell. Traditionally this was done by placing the shell in an 1800F furnace and allowing the wax to melt out. More common today is the use of a high temperature high pressure steam autoclave to achieve the same results. The autoclave also allows for a better reclamation of the liquid wax with minimal fire risk. After processing to remove contained water and filtering for solids, the wax can be reused in the production of new wax patterns.