When a sufficient amount of the right mixture has been obtained, it should be spread upon the wire form by means of a small mason's trowel or a large knife. It is well to begin at the bottom of the convex side of the cylinder, working upward, taking no pains to make this first coat smooth, since roughness is desirable, and paying no attention whatever to the inside of the cylinder, excepting to see that the cement is forced well through the meshes so that the whole mass will be held together firmly when dry. The inside is given a smooth coat as a part of the later finishing process. When the convex surface has been well covered, the form should be turned bottom up and the cement spread upon the base of the cylinder in the same way. After the wire has been completely covered, the form, which is likely to be somewhat distorted, should be corrected by careful manipulation till a true cylinder has been obtained. This is allowed to stand for about five hours until the cement has thoroughly hardened. It is then ready for the finishing coat.
The next step in the process is to make the cement for the finishing coat. Considerable variety is possible here, depending upon the colour and other surface effects that are desired. In this design a light, sparkling surface when finished is required. To produce this effect a mixture of one part Portland cement and two parts marble dust will be needed. This should be mixed without hair to a consistency like that used for the scratch coat.
Before applying the finishing coat the surfaces should be thoroughly moistened by means of a brush well filled with water. There are various methods of applying this coat. The simplest is carefully spreading it on with a trowel and smoothing it with the moistened hand. When the surface has hardened sufficiently it is sometimes possible to improve the finish by the judicious use of sand-paper or a coarse file. It is not possible to produce perfectly even surfaces in this way; and yet the method has the characteristic freedom of handwork in general, and yields very satisfactory results.
_The Decoration._--A great variety of decorative effects may be obtained in concrete pottery and in other articles made of this material for out-door use. In pottery these decorations may take the form of raised figures or ornaments, of borders or designs cut in the surface, and of inlays in colour. Whatever the form of design, the necessary cutting for it is best made when the cement has become well set but not very hard--_i. e._, from 6 to 10 hours after the finishing coat is applied. A stout, sharp, pointed knife blade is all the tool that will be required. A narrow chisel, however, may be found desirable for deepening the cuts. The knife should be guided by means of a ruler, which should be flexible if used on curved surfaces; and the depth of the cut will depend somewhat upon the size of the piece. In work similar to that described in the problem just given, a depth of 3/16 or 1/4 of an inch is sufficient. This cutting, of course can be made after the cement has hardened, by the use of hammer and chisel; but it will be much more difficult.