132r - - - - - [continued]
not to heat your mold too hot because it makes it brittle, it makes bubbles and shrinks tin, and would also break the molded thing. Do not dip you hot mold into water because tin and lead would shrink.
Mold made from two casts
It opens once anealed. To clean it after, fix the clamps again, lute the mold, particularly the joints. Then let the earth slowly dry. When it doesn’t smoke anymore, let the mold cool down until you can hold it without burning your skin. Then put your molds into the presses, or into a pot filled with sand, and cast with tin. If you cast gold or silver your mold needs to be cast twice, and cast when your mold becomes red—hot.
at left top margin
If your heated mold …, shrinks because of the bad quality of the plaster, open it after the first heating, tighten it, the lute it and clamp it again.
How to anneal the molds
Light your charcoals from the forge, then place them in a line in a corner of the forge according to the size of your mold, in order that it be surrounded with 3 or 4 fingers of charcoals, particularly at the bottom of the mole, where it is thicker. Then put your molds on these charcoals —— and not on a grate as some people do —— because they would get too strong a heat. Let your furnace heat up gradually for a while, always adding burning charcoal. As long as the mold is humid, your charcoal will be dampened at the bottom, but when it is dry, the charcoals start to blaze. When one side of the mold is dry, turn over; when both sides are dry and don’t smoke anymore, increase the heat and cover your mold with burning coals. When the mold starts being red, do not blow on it with small bellows, because the mold would burst. Similarly, when your mold becomes red—hot, keep it well covered with burning charcoals and do not uncover it because it would crack. Prevent the draft from a window from reaching it. Then let it cool down.
at left middle margin
When you want to anneal your molds, luted or not, do mark the belly of your mold, in order to place that side at the bottom, against the burning charcoals, because if the intensity of the heat made the mold crack, it would be better that it do so on the bottom part instead of the top part.
at left bottom margin
If your mold is small, do not heat it as long, otherwise it would crack and be damaged.
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