CHAPTER 10

Color Cement for Bowls and Vases

THE COLOR FOR BOWLS AND VASES is mixed the same as for the tiles and it will be found that the use of the muller to grind the color is necessary to secure a good mixture. The color should be of the right consistency for rotating inside of the molds, which can be best determined by a trial. It will fall off the sides if too thin and if it is too heavy it will fail to roll evenly.

TO PREPARE A VASE OR BOWL MOLD for color, the parts to come in contact with the color should be oiled after they have been immersed in water. The parts are then assembled and tied together. Corresponding marks or figures can be placed on the molds so that there can be no mistake in combining the correct sections. Such marks will avoid confusion, particularly where the mold may be composed of a number of sections. Molds for vases are not shellaced.

THE FIRST ROTATION is then made by taking a quantity of the color cement or slip, mixed only with neat cement of thick quality, and pouring it into the mouth of the mold into the bottom. A spoon may be used to place the color if the mouth of the mold is large enough. The color is then rotated by turning the mold gradually until the color covers all the inside of the walls and the surplus is poured out into a pan. If the color at first refuses to attach to the inside, a few slow revolutions of the mold will generally overcome the trouble as the oil is causing the separation and is overcome by a few turnings of the color.

THE SECOND ROTATION is accomplished in the same way that the first rotation was but not until the first layer has fairly set. The surplus from the first mixture may be used. It is placed or poured carefully in and the rotating done and the surplus again poured out, excepting that it is poured out from the opposite side so as to equalize the thickness of the neck section of the vase or bowl.

A THIRD ROTATION may be necessary if the bowl is a large surface or if the slip used has been very thin. After each rotation the mold with its layer of inside color should be covered over with a damp cloth to prevent too rapid drying of the color. The second and third mixtures should be thinner than the first.

THE WALL MIXTURE is then rotated over the color stratas and is made of one part of cement and two parts sand. This mixture is necessary to give the bowl or vase strength and to make it waterproof. If neat cement alone is used the vase will check and crack in time, particularly if water is ever poured into it.

FOR SMALL VASES only one rotation of color is necessary and the second and third may be of cement and sand with a fourth finishing layer in color. This finish layer may be of any color desired within the range of color cements or of neat gray cement only.

THE FINISH ROTATION is the layer that will appear as the inside lining. This is made of color and neat cement and is rotated so as to cover the cement and sand mixture. This mixture may be placed in the mold after the vase or bowl has been removed from the mold, and this permits the possibility of carrying the inside color over the edge of the mouth and partly down the side as a decoration.

AFTER THE ROTATED COLORS HAVE DRIED, which generally takes from two to five days, the mold is carefully opened and the vase removed. Flaws or bubbles on the surface, if any, are corrected by scraping with a moistened knife parts of the neck that are not to remain and others filled in. The false neck or that portion that extends above the actual vase is now carefully trimmed away, leaving only the actual bowl or vase.

CARVING AND SCRAPING of the surface can be done while the surface is slightly soft which is soon after the bowl or vase has been removed from the mold. Glazed color may be placed into the spaces carved or scraped from the surface if the surface is moistened well with water, then adding neat cement over which the color is dripped following the instructions as given for the tiles.

TO HARDEN THE OBJECT molded it is immersed in a bucket of water and left for several days. If the surface has had color added to it after it has come from the mold, it cannot be immersed in water as the color would be floated off. It should have water poured on the inside and left to dry in a cool place.

TONING WASHES can be made of thin color and brushed onto the surface after the bowl has been well dampened. This will permeate the fine pores of the cement as well as gather into the crevices particularly of a carved or relief surface and if a contrasting color is used, it gives pleasing effects.

GLAZING BOWLS AND VASES is much more difficult than coloring tiles. The curved surface requires careful application. Prepare a quantity of desired color to be applied. Then spread it out in a pan or dish (a platter will do very well), revolve the bowl on the fingers so that the surface comes in contact with the color. The color will adhere and the bowl should be kept slowly revolving until the color sets. The bowl can then be filled with water and left to dry. If the bowl is kept in one position before the color is set, the moisture will cause it to run and mar the surface. After the first color has set an additional color can be dripped on at the top or other colors added into or onto this surface. Different effects will be possible, depending upon how soon the color is added to the first coating.

Dry color can be sprinkled onto the wet color and permitted to become absorbed, giving an interesting effect. The color may be applied with a brush or palette knife, and other ways of producing variations on the surface may be produced by experimenting.

A VASE FORM WITH MAJOLICA SURFACE will need to have the surface turned as it is worked upon. This can be done by revolving with the hand inside of it, or if too small turned on a right angle support, padded so that it will not injure the neck of the vase. The vase may have one end supported on something to keep the worked part from coming in contact with the surface. After a part has been filled in, it should be left to set for a minute before turning the surface, otherwise the color will drop out.

After the color is all in position, stand the vase upright and with a funnel fill with water and let it harden for several days. The water will supply the color surface with moisture preventing it from drying too rapidly.

Any cement surface (tile or vase) before it is very hard can have motifs scraped into it so that the design is a series of shallow openings in the surface. The color cement can then be dripped into these openings similar to majolica work and completed in the same way.

A vase with a plain surface can be made exceedingly attractive by adding a few simple motifs well chosen and placed on the surface in this way.

FOR SLIP PAINTING tile or pottery surface, various colors to be used should be mixed and ground on glass or marble with palette or putty knife until thoroughly smooth. The colors should be placed in order on a glass or enamel palette. Other hues may be produced by the mixture of these colors or lightened by adding a white cement. A small brush is used to apply the color. The surface to which they are being applied should always be damp and the complete surface to be colored should be done at one sitting. The tile or vase is then placed in water as previously explained.

It is best that the color be thin rather than thick, and avoid going over a surface a second time. A second stroke will destroy the lustre which will otherwise remain on the surface.

A VASE OR BOWL FORM to be used for slip-painted color will have to set a few minutes to prevent the color running when the bowl is turned for new working surface. The bowl or vase is carefully filled with water and left to set for several days, care being taken that no water drops onto the slip painting. The object worked upon must be set in the shade to dry, where nothing will come in contact with it.