118v - - - - - Casting in box molds
The same sand that was used in the reheated noyaulx, composed of plaster, brick and alum de plume as is said, is excellent for casting in box molds, and I have experienced it thus: I crushed the pieces which had come out of core molds in a mortar, dragging the pestle, because this sand is very doulx. I did not pass it through the sieve, because the alum de plume mixed throughout, which binds it, would not pass; but I ground finely upon marble what seemed to me too coarse. And having prepared it thus, I moistened it with sal ammoniac water, made of sal ammoniac, as much as the size of two walnuts, in a bottle of common water the same size as a bottle in which one boils tisane, or in a good pot of water so that you find the water fairly salty. I mixed throughout half a glass of sal ammoniac, two silver spoonfuls of spirits. Having thus moistened the sand in such a way that it took hold well, nevertheless coming apart easily, I sprinkled my medal with pulverized charcoal with a file to rid it of oil, and all other grease. It is necessary to avoid them, for they would hinder good stripping. I blew on my medal & molded it, and the female part of the box mold once filled, I marked & made a line on the reverse & edge of the medal, & on the nearby sand as well. In order that the second box mold take the imprint thereupon to indicate the place for making the cast, once filledthe female part of the box mold once filled I uncovered the outline of the medal and pounced the whole side with pulverized charcoal, and then filled the male part with sand. Once mad I separated the box mold and did not hit the corners of the medal to make it strip, because that knocks the sand and makes it crumble. Rather I struck the back of the box mold, retaining the obverse of the medal on the bottom, and it molded very neatly. If it had not stripped thus, I would have waited to remove it until the box mold had been dried out over fire. I lit a row of charcoals between two little trivets of iron in the form that you see, and put the back & reverse of box molds thereupon, & the imprint on top,
Figure
because in this way, they dry out gently. And if, by chance, they should crack from being too moistened, it is on the back that they take the harshest fire, & the imprint remains safe & whole.
at left top margin
For the best, it is necessary to reheat the sand that is used in the noyau rather than used it in the box mold, until it no longer contracts.
at left top margin
Excellent sand
Take a little of the same sand, the finest that you can, for covering the medal.
at left middle margin
For medals & flat things, the true heat of lead & tin is when it is melted gently.
at left middle margin
Note that I filled the box mold before pressing it, and did not hit it, but rather pressed it with the strength of my hands alone, because hitting it makes it go awry. Secure your box mold that it does not shift at all, & if you put some moistened sand under it, it will only hold in place more firmly.
at left bottom margin
Make the gate that it is not too thick, so as not to overcharge the medal, but wide enough near the medal that it embraces a third part. Do not forget the vents.
at left bottom margin
Drying box molds is to keep them from humidity, that they no longer smoke, once having nevertheless been very hot.
at left bottom margin
Recuire is to redden the box mold, which is done for gold and for silver.