CHAPTER 9

Modeled and Carved Color Cement

FROM A STANDPOINT OF GOOD DESIGN modeling, when applied to a flat surface or any other surface, should not be high in relief.

Any time that a modeled design appears to have been added onto or is in such relation to the surface that it appears to be an independent, detachable ornament to that surface, then it is not truly decorating the surface, but detracting from the object decorated.

At all times keep the principles of unity and subordination in mind when producing modeling so that the design will be a related development to the material and the surface used.

CEMENT TILES WITH A MODELED SURFACE are produced as follows: Take a flat, smooth piece of clay or modeling wax, cut to the size of the tile to be produced. Such a surface may be made by rolling clay or wax with a rolling pin or other rounded surface. Having drawn the design to be modeled on a piece of thin paper, place this over the clay and trace lightly. This will produce a slight indication on the surface sufficient to guide the modeling. If there are sections that are to be low, these parts are outlined with an incision in the surface and scraped out to the desired level.

Do this over the entire surface, bearing in mind that the edges of the tile should generally have a border or other parts retained of the original surface. Too much elimination on the tile edge will thin the tile and weaken its construction and design.

Having scraped out all the low parts, then clay or wax may be added to such parts that are to be higher than the first surface. With the modeling tool shape the parts, finishing them so that there are no overhanging edges.

When this is completed surround with the plaster bars and produce a mold in plaster which in turn is oiled in the usual way and a cement tile cast from it. Neat cement should be poured first, and after a few minutes setting, a concrete mixture is poured in until the desired thickness is secured. In this way a cement tile is secured, duplicating in form the original clay or plaster hand-made modeled tile. The color of the surface can be any color according to the color added to the neat cement mixture.

DIFFERENT COLORS on different parts of the surface can be produced as follows: Mix cement colors with equal parts of cement. Grind these colors with the putty knife or pestle and place each color in a small saucer or pan. Oil the surface of the mold with a brush, dabbing it on in short strokes. The colors are next dripped from a brush onto their right location. This layer of color should be about a quarter of an inch thick and left to stand until firm on the surface. It is then covered with a layer of concrete and smoothed off to a level.

TEA TILES OR LARGE TILES for inserts into garden furniture or for architectural use can be strengthened by a reinforcement. A reinforcement may be made from the ordinary window screening or any wire fence mesh or so-called hardware cloths used in building construction.

This wire should be cut a little smaller than the tile and sunk into the concrete layer while soft. It should be pressed down with the fingers until the concrete closes over it. This will add a considerable strength to the tile.

After the tile has set for several days, it is removed by inserting the knife between the edges and carefully prying it apart, or steaming apart by placing over a low flame for a few seconds. If part of the color remains sticking to the plaster mold it is because there was not enough oil on that particular spot. Therefore remember that a mold surface should be well oiled before placing the color into it, and care being taken that there is not so much oil that it settles in the hollows and grooves.

The tile after drying thoroughly may be polished with wax and used.

FOR MODELING LARGER OBJECTS such as flower pots, urns or similar forms, it is best to form some means of reinforcement to approximate fairly closely the final form of the object. Close meshed wire can be used successfully for this purpose. It should be tied and braced firmly so that the concrete or cement weight will not destroy its shape. The concrete mixture should be made with one part cement and two parts clean sand.

TO HASTEN THE SETTING OF CEMENT add a very small quantity of common washing soda to the water used in mixing the cement. This will cause the cement to set up rapidly so that the work can be done more quickly.

AFTER THE MIXTURE HAS BEEN APPLIED over the wire reinforcement and shaped and modeled until completed, it should be put in some covered place or in a moist location for the first two or three days so that the moisture in it will not evaporate.

TO HARDEN THE CEMENT OBJECT immerse it well in the water for four or five days. If it stays longer in the water it will not hurt the object. The water will harden or complete the action of hydration necessary to make cement durable.

TO SECURE BISYMMETRIC SHAPES to forms or to secure true circular shapes, a templet of sheet metal can be cut and rotated from a centrally located axis. This is used while the mortar or concrete is in plastic condition so that the templet will cut or model the right contour.

CARVED CEMENT is made possible by scraping or carving out the cement when it is in the right condition. This condition can be determined by scraping the cement to see whether it is hard enough to carve. If it is too hard, it cannot be carved successfully. About sixteen to twenty hours setting will produce about the right condition but this will vary according to the mixture and climatic conditions, as temperature will be an important thing to consider in all color cement work. Very hot weather is not a good time to do color cement, the winter days or gray cool days are best to work with cement for perfect hardening results. Avoid freezing weather.

TO CARVE CEMENT, the tools may be of metal or nails shaped with cutting points and the work done similarly to the carving of the sgraffito tile described in the previous chapter. No adding or building of parts is possible, the whole subject being a process of taking out parts and shaping the parts that are left. Backgrounds and portions can be varied in texture and different results will be secured with a little experimenting.

DIFFERENT TEXTURES are possible in the carved tile. A glazed surface to the carved tile is secured by carving on the upper side of the tile; while the dull under surface, the side molded against the glass or under surface, will be used if a dull surface for the carved tile is desired.

A GLAZED OR MAT FINISH BACKGROUND in the carved tile can be secured by immersing the tile in water for a day or two for glazed finish or an hour for a mat finish and then applying neat cement, plain or with color as described in the chapter on Color Work for Tiles.

CARVING ON BOWLS AND VASES and other forms can be done, care being taken that the carving does not go so deep as to weaken the surfaces. Motifs or spaces can be carved out of cement bowls and vases and bits of stained glass or mosaics, or color cement can be put into the spaces and neat color cement used to bind the additions into the spaces.

SLIP-PAINTED PORTIONS MAY BE ADDED to the carved tile. After the tile is carved and properly moistened in preparation for the cement to be added, the color cement is mixed to a thin slip and a background pattern or decorations can be added to the surfaces of the carved tile. The tile is then placed in shallow water without permitting the water to reach the surface of the tile, and permitted to remain for four to six days before removing. It should then be placed in a cool location until completely dried.

THE UNIT TILE or the small tiles made to be assembled in patterns, may have modeled or carved cement surfaces combined with the units to complete the pattern. For instance a number of tiles representing leaf forms may be combined with others representing flower motifs. These may be imbedded into a panel of cement or concrete, the units grouped in some form of design growth, the stems and other related portions being modeled in the cement, or carved in the surface after the cement is somewhat hardened. The units can be in color or mat finish, the background remaining in dull finish.

MODELED CEMENT TILES differ from the cement tile with a modeled surface. In the first the modeling is done on wax or clay and the cement tile is made by duplicating the effect by the use of plaster molds. The modeled cement tile is a modeling of the cement by hand while it is still in a plastic stage.

TO PREPARE CEMENT FOR MODELING, pour a concrete mixture into the mold so as to allow for a second added layer of about one quarter inch of neat cement. This last layer of neat cement is the part which is to be modeled and can be made into a color by the addition of color to it. This color should be added in the dry form to the dry cement, mulled or ground well into the cement and then mixed with water until it becomes a thick cement paste that will pour slowly onto the concrete mixture first placed in the mold, until it covers the entire surface. A gentle jarring of the mold will settle the color evenly and it should then be permitted to stand until of a good modeling consistency.

A GOOD MODELING CONSISTENCY for cement is determined by testing it with a tool or small pointed stick making a small incision or trying a small section to see if the mixture holds its form. If the cement as laid up on edge stays in position and does not have the tendency to fall or settle, it is then ready to model, as it will hold its form when built in relief.

PROMPT ACTION IS NECESSARY when the mixture is at this point and the tool should be promptly used scraping or sketching the subject by incised lines in the surface. Then parts of the cement are scraped from the low portions and placed on the parts to be in higher relief until the general rough forms are massed in. The smaller parts are then detailed in and the different parts finished just as one would in working with clay or modeling wax. If it is found that parts do not hold up, it is because under sections of the cement have not dried sufficiently and it will be necessary to wait until it hardens a little more.

THE FINISHED RESULT may be complete with the strokes of the tool or the modeling instrument showing over the entire surface.

If the technique is shown in this way, care should be taken that the strokes are pleasing in direction and not carelessly left. As the tile hardens it will be found that the surfaces or edges can be shaped, and even when the surface is almost hard, it can be slightly indented or carved to produce different textures and varying qualities.

GOOD MODELING TOOLS are those that are made from pear wood for sculptors use. Metal modeling tools also can be used. Good home-made modeling tools can be made from manicure sticks, pencils, dowel sticks or ordinary small hardwood pieces shaped with a knife. These pieces should be smoothed down very evenly with fine sandpaper and then rubbed with beeswax or paraffin to avoid any rough surfaces. Rough surfaces will cause the cement to stick to the tool. Experience will be a good guide to the worker in color cement for determining the best shape to make the modeling tool, as individual needs and ways of working will determine the best form for each person.