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Marble finishing technology
As you know, all colored marble varieties are very expensive. As a result, artificial coloring of more affordable white marble is widespread in recent times. The staining method is as follows:
Unpolished marble is placed horizontally and covered with a dye solution (see below), so hot that it foams. The dye at the time creeps into marble deeply and holds very firmly. Coloring solution is prepared in alcohol. For dyeing in blue paint, a litmus is dissolved in alcohol, and the number of the latter is determined by the desired color density. For yellow color, gummigut solution is used. And if you put a second one (with a gummig) over the first color (litmus), you get a great green color.
The solution of alkane root prepared in this way, cochineal, etc. paints marble in red. Finally, a solution in alcohol of equal parts of zinc vitriol, sal ammoniac and also verdigris paints marble in a golden color. You can make a very spectacular mosaic of pieces of marble of different colors, painted in this way: in its beauty and color, it is not at all inferior to a mosaic of expensive varieties of marble, although it also costs much less.
Marble paint also alabaster
Not every paint is suitable for coloring marble or alabaster. In order for the paint to become firmly held, it must be prepared as follows: make a solution of borax also of a vegetable coloring matter, only then add a few drops of nitric acid or some nitrate salt to this solution. For example, to color the marble blue, a solution of indigo borax is also prepared; a few drops of nitrogen-iron salt are also added (as a liquid). For coloring in scarlet paint dissolve any red vegetable paint with brown. By replacing the coloring matter with ink nuts, a durable black paint is also obtained for alabaster marble.
Post hard gypsum
It is known that gypsum, mixed with water and then hardened, does not have any strength: it becomes extremely fragile and therefore finds itself with relatively little use. In order to eliminate this flaw, also to give the gypsum greater hardness, the following means is used in America: 6 elements of gypsum are mixed with 1 part of hydrated lime also with this mixture and then manipulated, as if with ordinary gypsum.
Items made from such a mixture, after a good drying, are impregnated with a solution of zinc vitriol. Objects made of gypsum, treated in this way are much stronger than ordinary plaster crafts.
Prepare a thick solution of gum arabic and use a brush to cover the marble with it, only then allow the gum arabic to dry completely. When the latter dries, it is separated from the surface of the marble (dried gum arabic easily lags behind marble), and, together with gum arabic, all extraneous substances that pollute the marble, which are difficult to remove by washing the marble, are also removed.
Another way: prepare a mash from 1 weight part of chalk, the same number of finely ground pumice as well as 2 soda elements. From this mixture, a paste-like mass is prepared on water, with which the contaminated parts of marble are covered, then washed with soap and water. To remove grease stains, the latter are covered with chalk: chalk in powder form is poured onto the marble with a sufficiently thick layer, after which the chalk layer is well wetted with gasoline only to eliminate the rapid volatilization, the final chalked with gasoline is covered with a saucer tilted upwards. After a few hours, the chalk is removed and, if there is still a greasy stain, the same operation is again repeated with fresh chalk, also with a new portion of gasoline. another time the marble is covered with rusty metallic stains. To remove them, they do this: in ammonium sulphide, clay of good quality is melted down to obtain a pasty mass. A lot of this impose a fairly thick layer on the spot. After 10-15 minutes, the mass is removed and a fresh portion is applied, which after 5 minutes is also removed, after which the marble is washed with water and also dried. If the stain still remains, then at the time they start the secondary finishing: the spot is covered with a pasty mass prepared from 1 weight element of a snow-white bolus and 4 parts of potassium synergistic solution (poison that requires careful handling). This mass is left on the marble for 30 minutes, after which the same operation is removed and repeated; then the marble is washed also dried. Thus it is possible to remove from the surface of the marble, even the oldest metal rust spots