Making multiple wax models in clay


    This article shows how to utilize clay in making wax models for lost wax casting, both for initial forms and for multiple copies of the same form. Archaeological evidence for this can be shown to some extent by the number of cast pieces found with woodgrain impressions, indicating that the original pattern was made from wood. Further rational on this will be presented in another article, but for now lets get to the process.

    Here are the basic componants. This is for a set of hinges. Patterns were roughed out in wood. This pattern is then lightly coated with talc (baby powder) and pressed into the wet clay. This particular clay is of the stoneware variety. Further refinement of the pattern can then be done by tooling the clay (such as the raised border and the 'eyes'). Wax is then carefully heated and poured into the clay. The wax must not be too hot or it will stick to the clay, which makes removal difficult (but not impossible). As the wax cools it will contract leaving dimples in the surface. These can be refilled as it cools.

    It is also possible to make a 2 piece mould by talcing the face of the first clay piece and pressing a second piece on top with the model inside, then removing the model and gently pressing the 2 halves of the mould back together, just enough to seal it. It's tricky but it will work.

    When the wax is completely cooled, gently remove it. If you're gentle, and the wax was not too hot when you poured it, the clay mold may be still be intact and you can pour another one without touchup.
    Excess clay can be removed by gently brushing and water. Flashing can then be removed and the back leveled. You now have an initial form to start carving.

    Carved pattern


    Here is one of the hinges with detail carved in. I can make up several blanks and carve each of them different.

    Brooch Blanks


    Here are multiple disk blanks from a chip carved wooden master.

    When finished, these can then be used for lost wax casting of finished pieces or as models for piece molds (2 part clay molds).