Making a casting mold

Creating a Flat or the Birth of a New Figure

Almost always it starts with a thought, an idea, a wish. 

1st Rough draft

The first step: designing

The designs are transferred to transparent paper, this was used to trace the lines to the engraving surface of the mould.

Designing figures is a complex work to do because there are so many things you have to refer to in order to create a good figure. Research is essential to guarantee historical accuracy especially for all the details of anatomy, costumes, uniforms, arms, heraldry, equipment and accessories. Perspective and positions are important for designing figure groups which share a common base. And a flat has a back side as well, so the artist has to invent this to match all the perimeters of the front view. It is really an art to create an accurate drawing with all those detail for a figure not larger than 30mm.

Second step: engraving

The start are drawings on the transparent paper are needed to start the work. 

Slate still today remains the classic material to create a mould. You need two congruent halves, firm and flawless, of good quality and of an appropriate size because the mould not only houses the figure but all the required air channels and the channel for the metal inflow as well. After having polished the two engraving surfaces engraving itself can start.

The outline of the design of the future figure is traced onto the first slate in reverse. Engraving is not easy as it means to work in mirror-image, i.e. with the mould you create a negative form from which a positive figure will be casted. Engraving means to cut away all the parts in different layers that will make the future figure. The engraver checks this progress by pressing modelling clay into the parts of the mould already engraved.

The second half of the mould is engraved in the same way. Congruency of the halves is guaranteed by corresponding holes drilled through the corners of both halves of the mould.

Final tasks for the engraver are to cut the base of the figure, the air channels or pipes and the inflow channel for the metal. The form and length of the inflow channel is important because it affects the pressure and airflow of the molten metal and that is essential for easy casting. 

Third step: casting

In my case Regina was not only the person who engraved but she did the castings as well. The flats, we call them tin figures, are made from an alloy of 60% tin and 38% lead and about 2% antimony to serve as a running agent, i.e. they are made from pewter or white metal. The quality of the alloy is essential because it affects the casting process. Every editor of tin figures has his own alloy which he keeps as a secret.

This alloy is given into an electric melting pot used by nearly all casters. Next the mould has to be prepared for casting by warming it slightly to prevent bursting when it gets into contact with the hot metal. Then the two halves of the mould are dusted with talcum powder to guarantee a smooth inflow of the metal. Some casters soot the mould by holding each half over a candle to get the same effect as can be reached by the talcum powder.

Then the hot alloy is poured into the mould and after a few seconds the casting can be removed. A new figure is born ready to be sold to all the collectors longing for it.