Harper's indoor book for boys

by Joseph H. Adams

Rubber gloves may be used for this purpose, but if a pair cannot be had the plate may be raised from the tray bottom by means of a small, sharp-pointed stick, and it should then be grasped with a pair of pliers and immersed in water to stop the action of the acid. A plate may be repeatedly removed from the bath to watch the progress of the etching, but in doing so it must be handled with care, in the manner just described.

When the ground is etched deep enough, remove the plate from the acid and give it a thorough washing in clean water; then with a soft cloth dipped in turpentine rub off the entire surface of the plate. The turpentine will dissolve the varnish and leave a film of it on the granular surface of the metal eaten by the acid. As a result, the ground will be darkened or oxidized, while the parts originally protected by the varnish will be bright and smooth. The high parts can be brightened still more with metal polish, or they may be buffed and lacquered by a metal finisher.

Some Typical Designs

In Fig. 5 the face of a door-knob is shown in its etched state, the pattern being drawn in varnish, as described.

In Fig. 6 the side of the knob in Fig. 5 is shown; that is, if it should have such a flat band all around. Plain brass knobs may be purchased at a hardware store, and if they are lacquered the coating should be removed with alcohol before the etching is done, as otherwise the acid would not eat through the lacquer for some time.

For an acid bath in which an object this shape is to be etched, a yellow earthenware bowl may be used, or a low jar with a wide neck will answer very well. The knob should be suspended in the acid by means of a piece of waxed string tied about the shank.

Hinges on cabinet doors may be greatly improved by making brass straps for them, which should be applied to the wood so that they fit closely against the sides of the hinges.

Fig. 6. Fig. 7. Fig. 8. Fig. 9.

Designs for hinge-straps are shown in Figs. 7 and 8, and Fig. 9 is a brass vase on the outside of which a floral design has been etched.