Fire-Proof Whitewash

Manufacturer and builder 11, 1890

It is found that a most effective composition for fire-proofing exterior surfaces may be formed by slaking a sufficient quantity of freshly-burned quicklime of the best grade, and when the slaking is complete there is added such an amount of skim-milk, or water in its absence, as will make the liquid of the consistency of cream. To every ten gallons of this liquid are added separately and in powder, stirring constantly, the following ingredients in the order named: Two pounds of alum, twenty-four ounces of carbonate of potassium or commercial potash and one pound of common salt. If white paint is desired a further addition is made to the liquid, though the whiteness is found to be improved by a few ounces of plaster-of-Paris. Lampblack has the effect of giving a number of shades from slate color to black. Whatever tint is used it is incorporated at this stage, is run through a paint mill. When ready to apply, the paint is heated nearly to the boiling point f water, and is put on in its hot condition. It is found that the addition of a quantity of fine white sand to this composition renders it a valuable covering for roofs and crumbling brick walls, which it serves to protect.