Equipment and Supplies Required
- Press or vulcanizer
- Shor Lok-Blok mold frame
- Typesetters metal or lead
- Dental stone or investment
- Lacquer or nail polish
- Fine line felt tip pen or similar marking device
- Lacquer remover, acetone or nail polish remover
- Plastic clay
Examine your model carefully. For every undercut, you will need to make a separate section in the metal mold. For example: a flat charm, requires only a two-piece mold because there are no undercuts. However, a setting will require at least three or more pieces because of undercuts. Sketch out, on a piece of paper, where the parting lines will be. Mark the parting lines on the piece with a fine line felt tip pen or similar marking device.
Process Overview
You will first create each section of the metal mold in clay. The clay will then be invested in the mold frame with dental stone or investment. With the removal of the clay, the metal can then be poured into the cavity left by the removed clay. The dental stone or investment is then broken away and the next section is created in clay, invested, the clay is removed and the metal is poured. Each finished metal section is protected from fusing to the hot metal poured into the next section by painting it with lacquer. The lacquer is removed after all the sections are poured. The metal mold is then reassembled and the gaps caused by removal of the lacquer are filled by placing the entire assembled metal mold, model and mold frame (with plunger) into a press or vulcanizer and applying pressure. The soft metal moves to fill in the gaps.
Step-By-Step Process
- Assemble the mold frame (without the plunger) and place your model in the center of the frame. Using the clay, mold the first section of metal mold. Be sure to define the limits of the clay to the lines that you have drawn on one section of the model.
- Pour investment or dental stone into the mold frame until the frame is about 3/4 filled. The investment will fill all areas inside the mold frame except the space taken up by the clay and your model. Remove the clay and pour the typesetter's metal into the cavity left by the removed clay. This metal will form the first section of your multi-piece metal mold.
- Break out the investment from the mold frame and clean the frame and the model of all debris. Paint the exposed portion of the typesetting metal with lacquer. The lacquer prevents the molten metal (when poured for the next section) from fusing with the exposed metal of the previous section.
- Follow the above procedures for each section of the mold until it is complete.
- When the mold is complete, disassemble the mold frame and the metal mold.
- Using lacquer thinner, remove the lacquer.
- Reassemble the mold and mold frame.
- Place the mold in the frame (place the frame's plunger on top of the metal mold) and put them in a vulcanizer or press. Tighten the vulcanizer as tight as it will go (or if using a press, use 1 ton pressure). This squeezing action will remove the parting lines that were left when the lacquer was removed.
- Remove the set and disassemble both the frame and the metal mold. Remove the model. The parting lines that were caused by the removal of the lacquer should now be gone. If your mold, at any time, loses its crisp detail through use, simply reassemble the mold with the model inside. Put it back into the mold frame and press it again. The sharp detail will be restored to brand new quality.