Founding recipes: salt, flux, fires and mould coats
Common salt on the bath, even flame-tongues, vessel-scale flux, and tallow behind the pour
A page of practical founding recipes for the bronze horse. Leonardo throws common salt onto the metal as it begins to form a bath, and moves any stubborn last piece off the cold furnace floor so it will melt with the rest. He calls for the flame-tongues at the flues to be kept level and prefers a single fire-mouth to two, and he fluxes the pour with the scale of a vessel to keep the metal liquid, throwing tallow or wax behind the entering bronze. A final note describes coating the ash with fine earth and flock-binder in successive half-dried layers.
On this page
Throwing common salt onto the molten bath
As the bronze begins to form a bath in the furnace, throw common salt over that bath.
Moving a stubborn piece off the cold furnace floor
When a large piece is the last to melt, shift it from its place, because the cold floor beneath it keeps it from melting along with the rest of the charge.
Level flame-tongues and a single fire-mouth
Always see that the tongues of fire issuing from the furnace flues are all of one height. It is better to make fire through one place only than through two, because one confounds the other.
Vessel-scale flux and tallow behind the pour
Casting scale of a vessel over the bronze as it leaves the furnace and enters the mould keeps the metal liquid. Behind the bronze entering the mould one should throw tallow or wax.
Earth-and-flock coats over the ash
Over the ash apply fine earth mixed with an equal part of liquid flock-binder; when the first coat is half-dry, give the second, then let it dry.