151r - - - - - [continued]
the white wax you have used to make black sulfured wax has so little substance, being dry and purified, that it leaves nothing with it the mold mentioned in the first part of this recipe and trickles very gently. As for the coal which is mixed in it, if there is some left, it burns and reduces to ash, and can be taken out afterwards by blowing into the cast. You can open your mold after the wax has been melted, if it does not contain a fantastical piece which could break, which are like pieces added on or similar. After having covered the clamps with lute from your sand, and having covered the entire mold, add to this a layer of common luth, and then sprinkle ground brick so that you can better manipulate it. Leave the lute to dry slowly, rather than putting it in the fire, which will melt the wax. The wax, having exited the cast, that which remains of it, mixed up with the charcoal, will burn. Having reheated it for the first time, lute it again, because should your plaster be bad, it will have eaten away at the mold and it will be found in the space between joints, which can result in large overflow. And for the second time, you must not reheat it if you want to cast only in lead or in tin, simply make sure that the lute is very dry and your mold attains an average heat. For those very large turtles that have enough thickness, it is better to cast using an alloy of half tin and half lead, as you do with hollow things. Because if you only need to cast very thin and fragile things like flowers, rely instead on using more lead than tin, which bubbles when cast a bit thickly and will easily some flaws to your cast. Master Alexander says he has never gone astray with using half tin and half lead for things that are heavy and as thick as the back of a knife. If there is crocum, you will not be able to clearly see the joints and as a consequence the metal overflow is very small and thin. You can repair this, and through the hole of the belly draw out the earth from the noyau, leaving it to soak for a long time.
at left top margin
When you have thrown your black wax in the mold and it has well—cooled, you will have to open half of your mold to make your cast. Should your black wax figure break, there is no danger, because it can always be reattached with a hot iron needle. Or if the pieces have not separated well from their mold, they will meet up and join as before, by joining and tightening the two halves of the mold. When your figure is big, you must interweave more iron threads inside to give support to the noyau. Figure
at left bottom margin
Aonly in lead or in tin. You must however heat the mold as much as if you were about to burn an animal inside, so that the wax melts well and leaves nothing inside, and trickles out while holding the mold slanted towards the cast and at the same time reheating it. And when the mold has been reheated, leave it to cool slowly, then blow inside and suck out the wax ashes. Do this with a bellows.
[continued]