119r - - - - - [continued]
When I saw that they did not smoke anymore, & scratching the back & the front of the casting & having found that they are rough & firm & hard on both sides, which is a good sign of their being quite dry, I leave them to cool down. I took some fine tin, one lb., & one ounce of fine & new lead. I melted it in a crucible just until it was a bit red. Being in this way quite hot & ready to cast & no sooner, I smoked every side of my box frame with the smoke of a tallow candle & pressed & cast & everything. I set my box frame, well joined, in the press. I drew my crucible from the fire. I let it sit a bit to quench the redness of the crucible’s bottom. And wanting to cast, I threw in around two or three grains of rosin, and about the measure of a bean of looking—glass tin & blended it & stirred the crucible a little and cast. And the medal came out as neat as the original. I smoked it with the candle & cleaned it with my coat.
at left middle margin
Always cast through the foot of the medal because the head, which is lower, will come out better, and make the casting somewhat long. And when you cast several medals in a large box frame, they will come out better.
Notice about everything above
Good tin is that which is hard as silver & soft nevertheless. If your work is fine, it must be almost all tin & alloyed as is said.
Looking—glass tin must not be mixed until the instant that you want to cast.
Nor must the forms be smoked until then.
If the sand shrinks in the box frame, this means that it must be reheated & turned red on the fire.
Good sand when moistened does not stick at all to the hand when pressed.
The perfect sand for the box frame is the asphalt found in Germany, which is soft as wet flour, & almost all the rest are lumpy.
Notathat the casting must be fine & hardly thick so that it does not work the material at all, & must not exceed the thickness of a grain of wheat taken crossw—wise, likewise for tin that is going to be cast finely. For lead, a little thicker. There is no need to make air vents very large & deep either.
The sand that you use à noyau for the said mixture is excellent for a box frame. But in washing, crushing & reheating it several times, its nature will be corrupted & it will no longer be fit to be taken & molded en noyau.