The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Coloring Finishing And Painting Wood
Some baking enamels can be produced without this valuable oriental oil. There has been something of a shift to lacquer enamels containing synthetic resins to take the place of enamels in which are varnishes made of China-wood oil and some of the new resins of chemical origin. There is considerably more "body" to synthetic-varnish enamels than to lacquer enamels, and this means that fewer coats are required for a satisfactory finish. Substitute oils to replace tung or China-wood oil are now being used in baking enamels made with synthetic resins, such as Bakelite. In some cases more linseed-oil is used. Recently, many manufacturers have replaced about 60% of the needed China-wood oil with Oiticica oil, which is marketed in Brazil, South America. Good results are reported also from at least two synthetic drying-oils.
353. Cleaning Metal.—Sandblasting is the preferred method of cleaning whenever a coarse surface is satisfactory and no polishing is expected. Steel wool of different degrees of fineness, especially the finer grades, and "wet or dry" sandpaper are also used in cleaning and smoothing. Sometimes a solution of washing soda, in a strength of two ounces to the gallon, is applied hot. Surfaces that are greasy or oily are often cleaned with gasoline and steel wool. After cleaning, handling with bare hands must be avoided. "Workers should always wear cotton gloves when handling cleaned metal. Experience has shown that paints, enamels, or varnishes will not adhere properly to galvanized iron, cast iron, steel, and some other metals unless they are properly cleaned.
354Pickling and Chemical Treatment.—Pickling in a dilute sulphuric acid bath is often recommended for castings to insure cleansing. The acid solution is prepared by using one ounce of full-strength sulphuric acid to three pints of water. The acid should be poured very gradually into the water. Another bath which may be used for dippings is prepared by the use of one ounce of sulphuric acid of full strength with three ounces of sulphate of copper and three quarts of water. All acid solutions should be kept in glass or earthenware containers, never in metal cans. An acidphosphate treatment has been found efficient in preparing surfaces of metal undercoats of synthetic-resin primers and enamels. This cleaner helps in adhesion of the primer or enamel to the metal. The solution should be rather weak but may be used in different strengths.
354. Gold Painting- and Bronzing.—This surface-coating material may be applied to various kinds of metal, also to wood, plaster of Paris, burnt clay and other materials, if suitable coats of sizing are used as undercoats. Bronze powders in a proper vehicle may be applied with a brush or spray-gun. Various shades of bronze dust, and silver, aluminum, and zinc powders are sold on the market. Prepared aluminum paints are also obtainable. Various vehicles or fluids may be used in mixing bronzing powders. Formerly, the so-called "banana oil" seemed to be generally employed.
