Making and Knowing
A minimal edition of BnF Ms Fr 640 in English Translation

- - - - - folio image: 089v - - - - -

Ammonia salt and alabaster

Dry ammonia salt, ground on a marble slab, molds very cleanly and is easily removed from the mold. When mixed with pulverized alabaster, use two ounces per pound of alabaster; it also is easily removed from the mold. It should be humidified in a cellar or in the cool humid evening air, or to have it quickly, in a sheet of paper in a moist towel. Take care not to leave it too long because it will soften, which would not be good if you wanted to use it as a box mold. However you can use it well as a core provided that you dry it gently and away from the fire. Otherwise the heat would make it swell, and push the salt onto the surface, causing lumps. If you want to mold a core, rub your medal with aspic oil. It is better to use 4 ounces of ammonia salt per pound. Humidify it in a damp place for two or three days, so that the material can be handled without sticking. You will mold very cleanly. Let the mold dry out and reheat it, that way it will get body, and become as hard as stone and when it is like that it is far easier to remove from the mold. If you do not reheat it, it could crumble when removed from the mold because of its thinness. It is the same with a large relief medal. Once you have molded, pulverize the material like before, and moisten it in a damp atmosphere. left—middleAll sands which can be removed easily from the mold have body, well—made fat ammonia, and is sand that removes easily from a mold. There is nothing better for binding than the salt of the metal itself. When ground into powder, they pick up moisture, dry and reheat together.