Black Varnishes
For patterns, alcohol 1 gall.; shellac 1 lb.; lamp-black sufficient to color it. Let it stand in a warm place, and stir occasionally. For castings, tar oil 20 lbs.; asphaltum 5 lbs.; powdered resin 5 lbs. Heat all together in an iron kettle, and be careful to avoid ignition. See VARNISHES.