THE BURNISHED CEMENT TILE is produced by casting a similar tile to the one made for the Traced Cement Tile and proceeding in the same manner, excepting that the spaces between the forms are burnished smooth with the dull pointed pencil or a smooth small stick. This results in some parts being burnished or pressed down while others remain in slight relief. A change in this is also produced by scraping the smooth surface off between the lines in certain places instead of burnishing it. This results in parts of the surface being of a different texture and also of a little different color, as the scraped parts are different in both these respects to the cement which has dried and remains untouched on the surface.
A SECOND BURNISHED TILE EFFECT is to pour a layer of neat cement first in the mold and a concrete mixture last. When this is hard enough to remove, and still soft enough to work upon (the neat cement layer having been in the bottom will dry with a dull finish and not a glaze finish as when flowed on as a top layer) it should be removed and the design traced upon this neat cement surface. If a leather tool or smooth hard point is used, certain parts as desired can be worked upon, smoothed down or pressed in, through the paper which will create a change of surface texture.
THE SCRAPED CEMENT TILE is where either the top neat cement or bottom cement layer has the design in line or form scraped out of the cement, the entire design being produced without a plaster mold being used. A sharpened nail or nut pick will make a good scraper and this scraping and pressing is done on the cement surface direct and not through a paper as in the two previous problems. This direct method of working upon cement surface is considered more thoroughly and more extensive applications made of it in the chapter on Carved and Modeled Cement.
THE CONCRETE TILE. Varying finishes may be secured in casting any cement tile by the kind of aggregate used with the cement. A rough irregular small crushed rock will give one kind of texture, while a round small white gravel will give another and each change will present different effects. Without going into extremes of finishes or having too many changes in the surface of a tile, pleasing effects can be secured by one to three changes of texture secured by putting different mixtures in different parts. This may be done by mixing and applying with a brush or spoon the different mixtures into the mold, placing the mixtures each in their proper section of the mold. The whole is then covered with the backing mixture resulting in the surface pattern appearing with the changes after the tile has been released from the mold.
Where a concrete mixture is to appear rough in texture, the sand or gravel and cement should be mixed dry, just enough water added to cause it to mix up to a damp consistency so that it can be shaped with the hand. This can then be put in the mold and tamped slightly with a block of wood to press it in true contact with the surface of the mold. This will result in a porous, open texture, producing good contrast with neat cement parts that have been previously placed or are to be added.
THE CEMENT AND CONCRETE TILE is made with plain cement producing added interest to the design by the two textures or surface finishes that occur between cement and concrete. The design for such a tile is best where the parts are separated either by an incision or a relief line. The plaster mold should therefore present separate portions, some of which can be considered for the cement parts and others for the concrete parts.
By mixing neat cement until it is of a thin mixture, the mixture can be placed on the mold wherever wanted by dripping it from a brush. Care should be taken in the use of a brush with cement that a wiping stroke is not used as such a stroke will remove the oil from the plaster surface and cause parts of the cement to stick to the plaster.
After the cement has been placed, a concrete mixture is made and poured into the space up to the desired height to produce the necessary thickness. This will at the same time fill in the remaining surface spaces of the tile.
THE GLAZED AND DULL CEMENT TILE is produced by filling in with clay or glued cardboard bits cut to shape, those parts that are to be glazed gray cement. Do not use modeling waxes or artificial clays for this part as the oil or grease in them will interfere with the glazed cement adhering to the surface in the final finishing.
After the cardboard or clay is dry a layer of neat cement is poured in, and backed with the usual concrete mixture. After the tile is released, the cardboard bits or clay is removed and cleaned out, the surface under it is roughened with scratched lines and the tile is put in water for an hour. The spaces are then filled with a mixture of neat cement and permitted to harden in a shallow tray of water.