Making and Knowing
A minimal edition of BnF Ms Fr 640 in English Translation

Secret for soldering small works made of gold and silver

If some little pieces of legs cannot be easily removed from gold or silver casting, it is because you didn’t cast wax under these parts. Beat some soldering gold very finely, then cut it into very fine flakes, cut the quantity you need. Take some of this phlegm or white and thick saliva which is on the teeth, put some of this matter to the place you want to solder with the point of a burin, then place your flakes, then put to the opposite part a mixture made of a small quantity of soaked fat earth and saliva, thanks to the mixture the solder will better adhere. Then pulverize a bit of borax on it, and heat up Quince pulp seed water to a boil and others too.