Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/434

426 the sponge all over before using, as frequently small portions of rock remain in it, the sharp points of which scratch the paint.

Strong Glue for Damp Places. For a strong glue which will hold in a clamp place, the following recipe works well: Take of the best and strongest blue enough to make a pint when melted. Soak this until soft, pour off the water as in ordinary glue-making, and add a little water if the glue is likely to be too thick. When melted add three tablespoonfuls of boiled linseed oil. Stir frequently, and keep up the heat till the oil disappears, which may take the whole day, and perhaps longer. If necessary, add water to make up for that lost by evaporation. When no more oil is seen, a tablespoonful of whiting is added and thoroughly incorporated with the glue.

Sulphate of Manganese. This is a pink-colored salt, useful, especially with zinc white, for exposure to sulphur gases. The following is the formula for its use: Sulphate of manganese 1 part, calcined sulphate of zinc 1 part, and acetate of manganese 1 part. These must be ground and sifted into a fine powder, and then dusted over 97 parts of zinc white. Another method for its use is: 6 to 8 ounces of sulphate of manganese to 100 pounds of ground zinc white paint, the powder thoroughly mixed with a portion of the paint, and this portion thoroughly mixed with the whole. Unless care is taken in the mixing, the work may be spotted.

Taking Grease out of Boards. Pipeclay and water mixed together until they form a thick paste, and spread over the part where there is a stain, will take out the grease very soon. Other plans are to cover the part thickly with dry fuller's earth, or a mixture may be made of 5 parts of fuller's earth to 1 part each of pearlash and soft soap with boiling water to make a paste, lay it on quite hot, and leave till dry, and then scour it with soap or silver sand and water. For simply making the boards a good color and