Investment casting method

An investment casting method for making a desired casting, which comprises:

• the step of preparing a thermally fusible pattern from one member selected from the group consisting of naphthalene and p-dichlorobenzene, with or without the addition of a small amount up to about 10% by weight of a polymer having a vinyl radical, which thermally fusible pattern is substantially a replica of the desired casting,
• the step of forming a refractory investment casting enveloping the thermally fusible pattern by coating a refractory slurry around said thermally fusible pattern,
• the step of melting the thermally fusible pattern so as to leave the refractory investment having a cavity that has been occupied by said thermally fusible pattern, said cavity having all the details of said thermally fusible pattern,
• the step of heating said refractory investment within an oven to remove all the residue of the thermally fusible pattern out of said refractory investment and to provide a rigid ceramic mold of one-piece construction,
• the step of pouring molten metal into said mold while the latter is heated to minimize the temperature difference between said mold and said molten metal,
• the step of solidifying said molten metal within said mold, and
• the step of removing the solidified metal in the form of the desired casting out of said mold.