081r - - - - - Sand
One can find an excellent one on the little hill of Puy David near Thoulouse for lead, tin & copper. It does not want to be too reheated much because, drying out all at once, it loses its stickiness & burns at the first arrival of metal, which makes the work lumpy & not neat. It is better to reheat from a distance, rather than with a straw flame, which generates des some filth. Before filling in the box mold, you can put in the finest sand you have in a very fine linen, & pound the medal dry and then the moistened sand that you put on top, which has more body, will grip it.
at left top margin
Tallow makes it porous.
at left top margin
Fixed mercury mixed in when one wants to cast, makes metal lead run. But if it is pure, one ought to cast very hot so that it runs, and vents.
Earth for molding
Tanner’s earth, or the one with which potters make a whitening on pots to make lead run better on them & to prevent the lead from being absorbed into them, is very good for molding the cavities of things you want mold in relief. It releases better than plaster or sulphur which become hard once they have set. For the earth being ready, one ought to be beat hard so that it does not crack. If the piece is very large you can mould it in several parts. If you reheat it, it is necessary that it be over a closed fire. One finds this earth at Fosseret & in another place called Ox.
Plaster
It is necessary that it be well heated, which you will recognize when cooking it in an iron or metal skillet, you mix it with an iron rod, & if it attaches to the iron, it is not heated enough, if not, it is good. The water with which you moisten should be a little warm & the mold made with the aforesaid earth also a little hot. The work of plaster does not last & the faces & delicate things break if one does not give a coat of glue.
Carton
One ought to take paper from Florence, which is the finest, & crush it & soak it several times & change the water every day, so that it does not smell bad, & since you will have moulded it in the cavity, put a linen over it, & from the back, rub the back of the paper with a tooth, as if you wanted to burnish it, and it will mould very neatly. Then glue the cloth on the back with strong glue.