153r - - - - - Moulding the hollow part of a mold for seals or other things
Firstly fashion your figure in wax on an even slab of glass or slate. After, mold it with our aforesaid sand, having beforehand lightly smeared with oil as you know, and having rubbed it with spirits, while tempering your sand with hot water. Having made the hollow part, cast it in lead, using the same alloy as you do for other figures that come out very neatly. However, if it does not release cleanly, repair it. And then mold with wax on the lead relief & you will have a very neat cavity in the wax that comes out very neat in lead. After, in your wax hollow part, throw in your tempered sand which will give you a relief, upon which you will cast your hollow part with silver, or any other metal used for seals. But note that you must not make your hollow part with melted wax, but only with wax warmed in hot water, or even better in hot urine. Or else, if you have a relief in gold or silver, or any other very neat and flawless metal, mold your wax hollow part directly upon it, and throw your sand in it wax hollow, which will form your relief, upon which you will cast your hollow part to make your seal or any other work. You could also cast a hollow part directly from the main part of your metal, even should you want to cast in lead or tin, which will not make the main part of your metal melt, if it has been lightly brushed with crushed chalk, or covered with candle soot, or with dried glair of egg.
at left top margin
When you have the wax imprint of your seal, mold in a noyau this piece of wax, which is hollow like your seal, and your noyau will make a mold similar to the imprint and the seal.
at left middle margin
Your wax must be mixed with a color that has little body, so that you may better see your imprint. The lamp black or soot black is good for this. White wax to do this is even better.
Giving a medal the thickness that you wish
Having cast your first mold, mix some crocum or well—ground iron scales to make it your mould firmer. And having taken hold, and made your hollow part very neat, take some paste made of fine
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