Making and Knowing
A minimal edition of BnF Ms Fr 640

[TOC] | [diplomatic]

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Watchmakers

Formerly, they dipping their springs by immersing them into molten lead. Today they dip their straight springs, & afterwards bend them, which is a beautiful secret.

Casting lead in lead

There are some who make their cavities with thick lead, then cast lead in them.
Lead when not cast hot enough, is white, & blacker when cast well hot.

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One can make a lead mold. & to cast in it, fumigate it with candle soot. But it is never that neat.

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Never does Lead come so neat as tin.

Sand

If it is too fat, one ought to reheat it and sieve it again.

Ways of casting in bronze

Latten of potin cor, which is the most brittle, molds more neatly, according to the opinion of many people, than fine latten of skillets, just like all fine latten molds neater than red copper. If you want to cast something fine & thin, the entire secret is to cast as hot as possible so that the substance boils. You will recognize that it is hot enough when it smokes a lot and while stirring it throws sparks. To heat well, place your crucible as low as possible & at the very bottom of the forge, so that the bellows fra beat on the middle of the crucible, for in this way it is better than on the grill on which one usually puts the crucible, under which the bellows beat. It is true that the crucible risks more danger breaking, but you can lute it as you know founders do. And also, one ought to maintain the charcoal between the bellows & the crucible. Also take heed to cast all at once & not in increments & drop by drop, which would stop & plug up the conduit of the substance. And if make in the cast an abreveoir to abreuver the medal, it would be even better. And so that the substance heats well at the bottom, stir it, once melted, with a wood stick, for iron only makes it brittle. Turn.

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Some put wool stuffing in order to heat it & make it run.

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Put under your crucible, one large iron platte, which will redden & will maintain the heat under your crucible.

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The copper substance is found to be good for casting, when once broken it makes the grain long & not short, for it demonstrates that it is soft. It is half fine latten & half red copper. This long grain is called long stalk.