The making of hammered copper or brass vessels is the same for etching as for pierced, perforated, or respousse work, but there is a fascination about etching that appeals strongly to the craft-worker.
Copper may be bought in several weights, but for simple objects, such as platters trays, No. 16 gauge is the best to use. Brass or copper sheets come in several sizes, and one must be chosen that cuts to advantage. Very few tools are required, most of which can be bought from a hardware dealer.
One pair of carpenter's dividers.
One pair of metal shears, No. 9.
Five cents' worth of emery-cloth.
A mechanic's vice.
A flat metal file.
A small wooden mallet.
A ball-pein hammer.
Etched Copper Tray, The Work Of Students Of The Pratt Institute.
Etched Copper Book Racks And Blotters.
A hard-wood block must be purchased, and should be 2 inches thick by 6 inches square. A depression must be cut from the end grain, leaving the top divided in two - half the original height, and the other half depressed. A glass developing tray, 8x10 inches, and some sheets of carbon transferring-paper will also be required.
For the etching, the following items must be purchased: -
One pint of nitric acid.
One pound of powdered pumice.
From a paint store: -
One pint of turpentine, and two soft brushes.
This list of necessaries will thoroughly equip the craft-worker for making simple pieces, and will last a considerable time for etching.
Plan the design on paper first, and then proceed to shape the tray. Place the dividers in the middle of the tray, and set them two inches apart. Describe a circle in the centre. . This will show the part to be depressed. The shaping is done upon the end ground of the hard-wood block, which must have already been cut to the depth of a quarter of an inch.
The block must be held steadily in the vice. Hold the copper upon the wooden block, so that the inscribed circle on the top is on a line with the upper edge of the wooden form below. The next process is the hollowing, by hammering the middle of the tray. Begin by beating just inside the circle, hammering the copper until the entire circumference has been completed. Continue this until the centre is all finished. Then straighten the rim by using the wooden mallet, pounding in on the side of the block. Many people use the bottom of a flat-iron in place of a wooder block, some preferring it to wood. The hammering must be continued on the rim until it is perfectly smooth and even. Some times this does not come at once, and need continual striking with even, regular blows If the copper is too hard, it can be annealed by heating until it is red hot, when it must be plunged into cold water. After this i will be found to yield readily to the blow of the hammer. Either the wooden of metal hammer may be used, or each suc cessively.
When the vessel is completed, the oute edges must be smoothed by filing with a emery cloth. The tray can then be cleane by heating slightly, and immersing in a bath of nitric acid, rinsing in water immediately afterwards, and rubbing with a cloth and powdered pumice. The tray is now ready to be etched.
If the artist does not wish to make the copper or brass pieces, all kinds of bowls and trays can be purchased undecorated, which can be treated in the following manner: - '
The design is drawn accurately on paper, and then transferred with carbon paper to the metal. Go over the design with a pencil, which will leave a slight indication on the metal. Then proceed to cover the design with asphaltum varnish, which must be of a consistency to drop easily from a brush. The asphaltum protects the metal from the acid, which is to be applied later. When painting the design with asphaltum, endeavour to keep the edges smooth by being careful that the varnish is not too thick. It may be thinned with turpentine until the brush moves easily. Not only must the design be covered, but the bottom, back, and edges of the tray, in order that the acid may eat only the exposed places on the background of the design. Two coats of asphaltum have to be applied four hours apart. If it is found necessary to change the design at all, the varnish can be scratche away with a penknife.
Take a glass developing tray, or a kitchen crock, and mix a solution of nitric acid and water - a little less than half acid, and a littl more than half water. Place the tray face u in this solution, so that it is more the covered as the acid evaporates. If the solution. is too strong, brown fumes will be given o and bubbles will rise to the surface. Mo water must be added if this occurs. Place the crock in some safe place, where it will not hurt the draperies. The fumes are rather disagreeable, so that a convenient place must be chosen; also, do not leave it where children could reach it.
Keep looking at the metal to see how the acid is working. It should be eaten to a little less than one thirty-second of an inch. Sometimes the design is entirely eaten through. All depends upon the wish of the craft-work as to the quality of the design. Remove the tray with pincers, and soak in a bath of kerosene or turpentine. The varnish may be removed by rubbing the surface of the tray with a cloth wrung out in turpentine. Cleanse the metal with powdered pumice, and paint it with a light coat of this spirit which will give it a slight colouring. Then heat slowly in an oven or over a gas plate, when it will turn to colours ranging from deep cadmium to purple.
Real individuality can be expressed in this method of ornamenting brass or copper. The work of no two craftsmen is exactly alike, some aiming to let the design be very delicate, while others prefer the acid to eat nearly through the metal. In making a design for a tray, it can either be continuous, or be run around as a border, or, if preferred, a design can be repeated four times at regular intervals. But, of course, the design must all be planned on paper first, and then traced on to the metal.
There are many suitable things obtainable at shops that can treated in this way - especially paper-knives and desk sets, which make interesting presents, even if the ornamenting is the only part that is original. Many people enjoy experimenting in chemicals, and making designs, who have no love of the actual working in metal, so that this craft is especially well suited to such people.