Wetting sand to mold flat medals
Flat medals, made of wax or metal, must be oiled very lightly and then touched with a brush of spirits. So that the already moistened mold takes well the oiled thing without rejecting it, one warms the water well in order to wet the sand, because with cold water it would be rejected. It is necessary to oil medals, because they do not expand and in this way would break the mold. Animals, which expand, do not need oiling. The hot water much be of such a heat that you cannot keep your figure in it without it becoming too warm. Wet the thickest sand for flat and solid medals rather than [for] lizards and finer things. Once your sand has set, clean and scrape your mold on one side and the other, and on the bottom edge of the thrown side of the medal, make a notch so that it is easier to take out. Lower the mold, scraping what surrounds the medal, so that on all sides you can take it out easily without it damaging the mold. Then make some gashes around the first mold used to throw so that the second time that you throw in it, it will be identical to the first one, and in the same way, make a notch at the bottom of the mold, where the held of the item cast lies. Also make some [gashes] in the sides of the cast. This done, wet the back of the first mold in oiled water, and after the second casting moisten it with warm water if you have molded your medal in a noyau mold. Having done the first cast, and this one having set, cut around the edge of the medal with the point of a knife so that it comes out of the throw and is not buried in it. Then having made the second cast, and having opened your mold, take away the medal in one go, with two knife points, one on the side of the cast object and one on the side of the head, which is at the opposite end.
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Take care not to oil your medal too much because if the seeps out, it prevents the sand from serving its purpose and coming together and renders it wavy and lumpy. You must only touch the middle of the medal with the tip of your oil brush and then smear the oil everywhere.
at left bottom margin of folio 137v
Make especially sure that the throw is as wide as you can on the medal and holds it together well. The gate of your cast must always be big and always narrowing as you go towards the medal. Also do not forget to notch the gate of your cast.
If you want to cast gold, silver, copper or brass, it is necessary that they be perfectly red, and fired on the inside when you cast, and perfectly reheated twice, if there is something inside to be burnt and cleaned.
The molds of animals that you burn must be reheated in such a manner that the animal burns up. But if it has big bones, it is frustrating to take out and ☿ often breaks delicate things because of its heaviness. One does not put ☿in molds that can open. It is often molds for flowers that do not open because they are cast in one go.
When you want to reheat your molds, fix cramp—irons on the joints, so that when they reheat they will not bend, contract or break. This is done once the cast is made.
The scrapings of the mold can also be used instead of bricks after being reheated, and also the leftover bits of the mold that have already been used. You can also pat it over important things, like works in gold or silver. You can also reheat it and blend it with water diluted with sal ammoniac, like spar from Germany, and is excellent sand for box molds for all metals.
The molds with things that need to be burnt out inside them, those ones will not open until the thing that is inside is burnt, like the molds for crayfish, crab, great—horned beetles. Do not open the molds in which you will burn something, not before the thing is burnt, it could be crayfishes, crabs, stag beetles, pictures, and pieces of wax and black sulphur, which do not come out of the mold [easily].
You must not mold on brick or wood because they absorb and attract water too early, and do not allow the sand to set. The best place for [the sand] is on a fresh layers of clay. And yet, I have experienced that grey earth dries out the mold too quickly. Yellow [earth] is better.
at left middle margin of folio 138r
For medals, and flat things, the sand must be quite thick and moistened so that it sets quickly. And when the sand is thusly thick, you can shake and move the table where you mold lies, so that [the movement] makes the sand go everywhere. But when the sand is clear, as for flowers and herbs, you cannot shake it, nor can you do it when there is something attached to wax or other things which are prone to come off, such as the legs of crayfish or other similar things. And if by chance your sand is too thick, you must quickly add some water. And having put the sand in the water, examine it until it is thick on the bottom and clear on top. The clearest is thrown in immediately and then bubbles and the thickest is thrown in at the end so that it strengthens the mold.