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Giving plaster products the look of antique bronze, ivory, wood, etc.

Giving plaster products the look of antique bronze , with ivory, wood, etc.

If desired, the surface of the gypsum product can be given the appearance of wood, bronze, cast iron, etc.

Before tinting, the product is well dried. Drying begins with 25 0С , it is brought up to 45 0 С and only at the end - up to 55 0 С. It is not recommended to raise the drying temperature higher and speed up the process. You can simply stand the product in a dry, warm place for several days. Then it must be soaked twice with hot linseed oil or with a solution of shellac and rosin in industrial alcohol. Drying oil or varnish is applied with a wide flute brush. Such a primer makes gypsum non-hygroscopic, and no spots form on the tinted surface. After priming, the product is again dried. Gypsum impregnated with drying oil over time takes on a form close to old marble. And the objects made of gypsum, covered with shellac varnish, resemble terracotta.

Waxing is just as simple. To do this, the surface of the gypsum product is covered with a solution of wax with turpentine or gasoline and a small amount of yellow oil paint. After 2 hours, wipe the product with a soft cloth until it shines.

Finishing the product “under the bone”, it is first treated with a “soap maker”. 30 g planed white soap is dissolved in a liter of hot boiled milk, cooled and bristle brush is applied to the surface. After drying, polish the product with nitro-varnish, slightly tinting the recesses with yellow oil paint. So that the surface does not shine, it is wiped with talcum powder.

When patinizing a gypsum product (painting “bronze”), oil paints are used, having previously selected them by color. For example, for a brown tone, the following composition is recommended (in parts by weight): ocher - 11, natural sienna - 33, soot - 28, turpentine - 70, desiccant - 70. For a greenish-brown tone: ocher - 120, natural sienna - 196 , soot - 9, greens - 6, turpentine - 200, desiccant - 200.

Paint is applied in 3 layers. The convex parts of the product are coated with a liquid composition, the recesses are thick. The first coat of paint should be light. After drying, it is lightly treated with a fine sandpaper and wiped with acetone. The second layer should be darker and thicker, for which a small amount of bronze powder is introduced into the composition. After the second layer has dried, the third is applied. It is diluted with turpentine, in which beeswax is dissolved ( 40 g on 500 g solvent). Wax makes the paint matte. Before the final drying of the third layer, it is slightly removed on the protruding parts of the relief. Then, the tinted surfaces are wiped with a soft flannel, powdered with talc, and in places that it is desirable to shade, with a mixture of talc with chromium oxide powder. To enhance the tinting effect, the convex parts can be sprayed with a mixture of graphite powder with bronze powder.

To imitate dark bronze, it is recommended to use light or golden ocher , natural sienna, natural umber, soot; for light bronze - natural umber, soot or natural sienna, light or golden ocher, chromium oxide or cobalt green, white lead or zinc.

Toning of gypsum products “under the old bronze” is almost identical to obtaining patina on real bronze:

one.   First, the gypsum product is impregnated with drying oil and left overnight. Then cover it with a mixture of bronze powder diluted in varnish, dried for 20 minutes and apply a second layer of the mixture. When it dries, the surface of the product is coated with the following composition: 10 g silver nitrate dissolved in 100 g acetic acid and diluted 300 g water; to obtain a particular tone, you can enter the appropriate pigments. A thin layer of bronze powder deposited on the product is oxidized by this solution. The more concentrated the solution, the stronger the film is oxidized. The treated product is either wiped with a velvet cloth or coated with wax dissolved in turpentine.

2.   To make the antique bronze look like gypsum figures, two solutions are prepared: 1) Flaxseed oil is boiled with a solution of caustic soda on soap, a solution of sodium chloride is added and boiled until soap grains are separated; the solution is filtered through a linen rag, the soap is squeezed out, dissolved in distilled boiling water and filtered. 2) 4 copper sulphate and 1 iron sulphate are dissolved together in distilled water, filtered, part of the solution is boiled in a clean copper vessel and the first solution is poured until a precipitate forms. Separating the green ragged precipitate, the rest of the solution is poured to it and again boiled; after some time, the liquid is drained, the precipitate (copper soap) is washed, first with hot, then with cold water, and finally squeezed it between the linen rags to dryness. Then boil 1,500 pure flaxseed oil in 375 minutest, filter through a linen cloth and put in a warm place; when settled, 468 oils are fused with 250 copper soap obtained above and 156 white wax in earthenware dishes, with moderate heating (best in a water bath). This mixture is applied by brush on a gypsum object heated to 70 ° ; when, due to cooling, the varnish is no longer absorbed, warm the object again and again varnish until the object is saturated with it. In conclusion, they put it for a moment in a heated chamber, then put it in the air until the smell of varnish disappears, rub it with cotton or a soft linen cloth and apply a small amount of bronze or gold powder to some places.

To simulate a cast iron casting, the gypsum product can be coated with a dark gray paint composed of ocher, white and soot on a drying oil mixed with desiccant. After the paint dries, the product is wiped with a dry mixture of graphite, mummy, ocher, white, ultramarine.

To make the surface of the gypsum product shiny, it is coated with a composition of 5 parts glycerol and 95 parts silicate glue.