Painting by Immersion and by Compressed Air: A Practical Handbook

by Arthur Seymour Jennings

It is important that the iron be dipped just as soon as it leaves the finishing shop, and it is necessary that the surface be thoroughly cleaned before the paint is applied, and particularly after all scale is removed. Sometimes the application of the sand blast is necessary for this work, but, as a rule, a vigorous application of suitable wire brushes will suffice.

Another very important provision is a system of overhanging rails on which the sashes or other articles can be run direct from the finishing shop to the paint tank, and thence to any part of the building, from which they may be taken as required for shipment.

The paint used for casements is usually grey, being as a rule made of zinc oxide and lampblack. These pigments, when mixed with a suitable vehicle, are very durable, while, the colour being neutral, it is suitable as an undercoat for green, as well as nearly any other colour which it may be desired to use as a finish. The weight of the paint should be 13 lbs. to the gallon, and it should dry with a semi-gloss. The elevating apparatus need only be of a simple character, and several casements can be suspended and dipped at one time. For this purpose a "hanger" is used, having perforations through which one end of the hooks pass. One form is shown in Fig. 21. By the side of the tank should be a large metal lined floor, say, 20 feet by 15 feet, or even larger, inclined toward the tank. The frames having been plunged into the paint, are at once withdrawn and hung in rows to dry over this floor. The superfluous paint drips on to it and runs back through a screen or sieve into the tank. The latter should be provided with a cover, to be closed in when the work is not being proceeded with.

Fig. 21.—Iron Hanger for Suspending Several Articles to be Dipped Together.

In this class of work it is unnecessary to employ a stirring apparatus provided that the paint is of the right consistency, and an occasional stirring up with a pole after the work has been suspended, say, for example, from Saturday to Monday, will usually be all that is required. As a matter of fact, the lowering and raising of the casements into the paint effectually stirs it up.

Metal Furniture.

Fig. 22.—The Automatic Finishing of Pianos.
Carrier Filled with Six Complete Pianos.

Under this head it is intended to include such articles as deed boxes, lockers, files and other metal goods which are required to be painted both inside and out. An enamel stoving or baking paint is usually employed for the purpose, while the tank must be of sufficient size to accommodate the various articles that are to go into it. Taking a deed box by way of example, a large iron hook, such as is shown in Fig. 32 is placed inside the box so that it is suspended at an angle; the box or boxes are then lowered into the tank and immediately withdrawn after all the superfluous paint runs away, care being taken that the box hangs at a proper angle to permit of this being done. Great care must be taken in this room to exclude all dust, which would considerably mar the work. For this purpose wire netting of the finest mesh should be placed over the windows so as to screen off any dust which might otherwise enter. A system of overhead rails are made, consisting of an L-iron on the top side of which run two rollers to which are attached hanging gears, and is sufficient for the purpose. At least ten minutes should be allowed for these articles to drip over the inclined floor adjacent to the tank, and for safety's sake it is as well to employ a workman with a brush in his hand to go over each piece and remove any tears or runs which may possibly occur. Metal work of the description named is then placed in a stove and baked for three hours at a temperature of 400° F. The paint is frequently green, which is found to be a good serviceable colour and which is attractive in appearance. After the baking the paint is quite hard, and will withstand more or less rough usage. If any ornamental work is required, this is done afterwards, as explained under the head of "Stencilling." The paint employed weighs 13 lbs. to the gallon, and a fine mesh paint strainer must be provided, through which the superfluous paint passes as it drips from the articles on their way to the tank. In this case, as in others, no special stirring apparatus is required, as the comparatively heavy vehicle and the relatively light specific gravity of the pigment employed gives little or no opportunity for any "settling out."