Varnish (Black) For Wood. Put 28 lbs. of common black pitch and 28 lbs. of common asphaltum into an iron pot: boil nine hours, and let it stand to cool for twelve hours; then set it again upon the fire, and as soon as it boils, add 8 gallons of boiled oil; introduce afterwards gradually 10 lbs. of red lead, and 10 lbs. of litharge, and boil until it will roll very hard. Leave it to cool, and then mix in 20 gallons of turpentine. This is a cheap black, and will dry in half an hour.