Color Cement Handicraft

by Pedro J. Lemos; Reta A. Lemos

TO MAKE THE PLASTER CARVED MODEL trace the design onto a smooth slab of plaster of the right size that has been cast on a smooth surface. If a larger piece of plaster than the desired size is used it can be cut down.

TO CUT PLASTER SECTIONS an old saw can be used or several strokes of a knife on the surface until about one-quarter of the thickness has been cut, and a similar cutting on the reverse side, just opposite to the cutting on the first side will enable the plaster to be broken easily. Or by laying it on a straight edge with the line of cutting over the edge, a quick pressure with the hand will snap the two pieces apart.

AFTER THE DESIGN IS TRACED a chiseled nail point, nut pick or other hard edged point is used for scraping the surface of the plaster, modeling it or carving it to the desired shapes. Naturally it will be found that plaster can only be taken off and not added on and that all reliefs must be produced from the surface downward, that is the natural surface will be the maximum height and all variations in the surface produced below that.

BACKGROUND TREATMENTS are produced where a design appears in low relief against a background. The background may be stippled with the tool point or lines scraped or crossed lines used to create interesting background qualities.

TO BUILD UP PLASTER SURFACES, roughen the surface onto which more plaster is to be placed and mix fresh plaster and place it on with a small spoon or with the brush. After this is dry it can be carved or scraped with the tools used in the modeling of plaster.

TO FINISH THE PLASTER CARVING, it is dried, shellaced, and used for casting just the same as the other relief forms described. To preserve casts from receiving injuries to their surfaces they should be wrapped in paper with a card against their face and placed with face toward the wall in a cupboard or shelf, when not in use. Where a mold has been repeatedly used and the shellac become worn, the mold should be carefully dried and the shellac coating renewed.

A CONVENIENT CLAY TO USE for relief work is the powdered fire clay secured in most hardware stores and is the clay used for lining grates, furnaces and similar purposes. This clay is convenient in that only the amount needed may be mixed up for use, leaving the balance of the powdered fire clay always in good condition.

RELIEF TILES DESIGNED FOR FLOOR SURFACES or for wall surfaces are best where they do not contain deep relief as they will not catch dust or dirt and will be better unified with the remaining surfaces.

SPECIAL TREATMENT FOR RELIEF FLOOR TILES is required in that the cement should be compact and clean sand should be used mixed with just enough water to cause the two to adhere to each other and this should be tamped into the mold well up against the face of the plaster tile to pack the mixture firmly and cause it to form into a durable surface.

TO HARDEN CEMENT TILES or pottery they should be placed in water so that the water will complete the chemical action producing the stone-like quality of successful cement work. If the tile is removed and dried and again placed in water it will increase the hardness.