All nail holes and cracks were puttied, and the entire structure down to the cement foundation was given three coats of white paint. Built in this manner, the pergola will stand for many years, and already the boys have planted wistaria, honeysuckles, crimson rambler, trumpet, and other vines to cover it.
The columns themselves may be easily made of concrete. The form may be made of six or eight inch iron pipe. When this is bought, have it split in half lengthwise at a machine shop. Six-inch pipe cut in this way will cost about a dollar a foot, but it will last a lifetime if protected from rust, and very often the concrete posts may be sold, so that the form will soon pay for itself.
Have a blacksmith make two iron bands, as shown at o. Have a 5⁄16-inch hole drilled at a through both ends. These bands are used to hold the two halves of the iron form together, and are tightened by a bolt and nut at a.
Dig a pit for the form to stand in, so that the cement may be easily poured in. This pit may be about three feet deep by two feet square, and the sides supported by a box without a bottom.
To make a column, clamp the two bands about the form, and place in the bottom end a circular piece of wood, with a hole in the centre to insure the iron rod being in the middle. Place the form upright in the pit, and secure it firmly by nailing strips of wood across the top of the box. Place the iron rod in the centre, passing it through the hole in the bottom. Pour in the cement quite wet, and tamp it down occasionally until full. It will settle a little, and will need to be filled to the top. A circular piece of wood, similar to the one at the bottom, may be used to centre the rod at the top. This must be done as soon as the form is filled, before the concrete has had a chance to set.
Use four parts of fine, clean sifted gravel to one of cement. Allow the form to stand four days. Remove the clamps, and draw the form out on the ground. Tap it gently, and remove one half of the iron pipe. Roll it over upon two pieces of board, and remove the other half. The concrete will be very heavy, and the assistance of a full-grown man may be needed to draw the form out of the pit.
The inside of the form should be cleaned and thoroughly oiled. This should always be done before making a column to insure its coming out easily, as concrete forms a strong bond with iron, and otherwise the column may be broken in trying to get it out. The result will be a perfectly round but not perfectly smooth column. It should be coated with a wash of clear cement and water, using a wide brush. The colour may be made white by adding a lump of lime to the cement and water, and two coats of this solution about the consistency of milk will be necessary. The last coat may be put on after the columns are on their foundations. The placing of the posts on the square foundations is heavy work and the help of a labourer should be secured.
These plain posts are not as ornamental as wooden columns, with their bases and capitals, but they make a very substantial structure that cannot decay and will last a century.