Copper Work Part 4

The solder may be obtained any gauge, but about 20 answers for most purposes. After cutting the solder into pieces about 1/16 of an inch long and about the same width, drop them into the borax that has been ground to give them a coating of borax and to remove any grease that may have adhered to them. Coat the surfaces that are to be soldered with the borax being careful to get no more borax about than is necessary. Put the parts together and bind them with No. 24 iron wire, not too tightly.

The pieces of solder are then lifted with the brush used for the borax or with a pair of tweezers and placed next to the edge that is to be soldered, about one inch apart. The object is then placed on the annealing tray, which answers for soldering as well, and with the blow-pipe it is heated, very slowly at first until the water has evaporated and the borax crystallized and dissolved, the flame may then be applied more directly and the object brought to a soldering heat. If the heat is applied too quickly, it will throw off the solder; and if heated hotter than necessary it is liable to melt or burn the parts being soldered, so the process demands the closest attention from the start.

The object is then pickled, washed in clear water and dried in the sawdust.

If the above directions are carefully followed good results may be expected.

REPOUSSE OR EMBOSSING.

Repousse or embossing involves practically the same principle as modeling in clay or wax, the only difference being that metal is used as the material and that different tools are employed. In this, as in clay or wax work, it is desirable to bring certain parts of a design into relief; to do this with metal the work must be placed on a substance which will give some resistance and yet allow each blow of the hammer or tool to make an impression. The substance commonly used for this purpose has the following composition, in the proportions given:

Black pitch 1 lb.

Tallow 3 teaspoonfuls.

Plaster of Paris 1/2 cup.

The pitch is put in some kind of dish (agate is good), placed over a gas plate, and melted. The tallow is then added and the plaster sprinkled and stirred in, the whole being well mixed. It is then poured into the pitch pot, or whatever it is to be used in. When used in hot weather more plaster must be used. A pot, hemispherical in shape, Figure 21, made of cast iron about 1/2 inch thick is generally used. This, when placed on a chaser's pad or ring, Figure 21, may be turned at any angle, and is found to be a great convenience. An ordinary 7" 12" baking pan of iron serves the purpose, or a box may be made of wood, but of course this is not so durable.

After allowing the composition to cool partly, yet while soft enough to stick, the piece of work that is to be embossed is placed on it, the right side next to the pitch. It is then allowed to cool still more; when quite hard or when it is difficult to make an impression on it with the thumb nail, it is ready to work on. The design is next drawn or transferred to the metal by the use of carbon paper and then scratched on with a scratch awl to make the drawing more permanent, as in going over the piece of work the pencil or carbon lines are easily erased.

The tools necessary for this work may be made as needed according to each individual design. There are a few general ones that are always found useful, such as those shown at Figure 5. Figure 22 shows a hammer generally used for this work.

[Ill.u.s.tration]

[Ill.u.s.tration: FIGURE 21.]

[Ill.u.s.tration: FIGURE 22.]

Chapter VI.

RAISED FORMS.

The first exercise in raising should be a form quite simple in outline, Plate 34 A. A drawing or blue print should be used showing the shape and dimensions and this should be worked to as closely as possible. Next select a piece of copper suitable in thickness for an object of this size, in this case 20 gauge. The metal for raising must be circular in shape and the diameter of the piece needed for this bowl determined in the following way:

Take a piece of string, place it on the drawing or blue print, starting in the center of the base, and follow the curve as indicated at A, on Plate 34. This will give the radius needed for describing the circle, which is 5-1/2". The circle is then cut out with the shears, after which another circle is described on the metal for the base. All lines made on the metal should be made quite lightly.

As a rule the copper comes from the rolling mill somewhat hardened so the next thing to do is to soften it by a process called annealing.

Place upon the annealing tray, Figure 1, the circular piece of metal already cut, and apply the flame from the blow-pipe upon it until it becomes red hot. It is either allowed to cool off gradually or dipped in cold water and then dried in the sawdust.

Select an anvil the shape of which conforms somewhat to the outline of the bowl and also to the curve of the base. It is often necessary to use several anvils to complete an object, but a little experience will help to decide which should be used first. The No. 1 anvil on Plate 1 seems to be about what is needed for this particular piece of work.

[Ill.u.s.tration: PLATE 34. RAISED FORMS]

[Ill.u.s.tration: FIGURE 23.]

[Ill.u.s.tration: FIGURE 24.]

The anvil is placed in the vise and the metal held in the left hand against the anvil so that the end of the anvil comes directly under the circle which represents the base, as shown at Figure 23. With a raising hammer, No. 3 on Plate 2, begin hammering with light blows at first, following the circle closely the first time around until the base is well started. This operation is continued at each turn striking a little above the previous blows until the top is reached when it will take the shape as shown at Figure 24. Sometimes a horn or box-wood mallet is used to start a piece of work. As the hammering hardens the metal it is necessary to anneal it each time after going over the surface. After this is done, we proceed as at first until the required form is obtained as called for by the drawing.

Care must be taken not to stretch the metal any more than can be helped as the more it is stretched the thinner it becomes.

The surface and outline of the bowl left by the raising hammer is quite irregular and needs to be trued up by a process called planis.h.i.+ng; for this a No. 2 or 4 hammer, Plate 2, with a polished face and somewhat broader than the raising hammer is used. By going over the surface with this hammer all irregularities are removed leaving a refined curve and a finished surface.

If the bottom gets a little out of shape during the operation of raising, it can be easily brought back again by using a No. 2 stake, Plate 1, and a No. 5 hammer, Plate 2.

During the raising process the top edge has also become very irregular and must now be trimmed off level. Place the bowl on some level surface (a surface plate will give the best results) and with the point in the surface gauge describe a line about the top making it the desired height, Figure 25. A small pair of shears is then used to trim off the top to the line, after which a file is used to finish the edge, leaving it perfectly smooth. A piece of fine emery cloth may be used at the last.

[Ill.u.s.tration: PLATE 35.]

The principle of raising as here described applies to forms of all sorts with few variations. Where a form is to be raised with the top edge turned in as at B, Plate 34, an anvil similar to the outline must be used. In raising a form like C, Plate 34, the sides are carried up as shown by the dotted lines and then the form is reversed and the neck part drawn in. A deep form is raised more quickly if, at the start, the metal is placed on a crinkling block and the edge crinkled.

[Ill.u.s.tration: FIGURE 25.]

In all raised work after one becomes acquainted with the material, it will be found that the metal can be forced in any direction, giving thickness at the bottom, at the sides, or at the rim, as is necessary.

[Ill.u.s.tration: PLATE 36. PITCHERS]

After raising a form like C, Plate 34, it may be desired to increase the diameter a little at o-o, where an anvil cannot be used; or, if the form is satisfactory it may be necessary to raise certain parts of it to carry out the decoration called for by the design. This is done by the use of the snarling-iron, made as ill.u.s.trated at Figure 26, which shows the general outline only, as the ends vary in form according to the work they are to do. One arm of the iron is held in the vise as at Figure 27.

The form is then placed over the end and held with the left hand while, with a hammer in the right hand, the iron is struck quite near the end in the vise which causes the other end to rebound. This serves the same purpose as a direct blow from a hammer, except that it works much more slowly.

[Ill.u.s.tration: FIGURE 26.]

[Ill.u.s.tration]

[Ill.u.s.tration: FIGURE 27.]

[Ill.u.s.tration]

[Ill.u.s.tration: PLATE 37.]

[Ill.u.s.tration: PLATE 38.]

Chapter VII.

PORRINGER.

The making of a porringer serves as a very interesting exercise; and it is so simple in form that it can be raised after very little experience.

A suitable handle must also be designed, sawed out and soldered to the body.

After the bowl has been raised into shape according to the design, the top is cut and filed off level. When the handle has been sawed out and the edges trued up, it is fitted to the bowl part. Mark on the edge of the bowl the place where the handle is to be fitted and fit it at that place. The edge of the bowl where the handle is to be soldered should be filed or sc.r.a.ped bright before the soldering process is begun.