The next problem in the graded series that we are following is that of the blotter, Figs. 12 and 14. For this we shall require one piece of soft copper or brass, 18-gage (Brown-Sharpe gage) 4 1/2" long by 2 1/2" wide for the top, and one piece of spring brass, 20-gage, exactly the same size, for the bottom. The construction of the blotter is as follows: First, paint the design on the top as usual, with the sapolin, but with this difference, that we must allow an extra 1/4" on each end for turning over, as shown in Fig. 13; then etch in the acid solution and remove the sapoliri in the manner outlined in the previous chapter. Beat up the design from the back on the block of wood with the ball end of hammer, getting it as smooth as possible by hammering the design on the smoothing-stake (which will fit in the base-plate) with either end of the hammer ; then place it flat, design upward, on the lapping-tool, allowing the extra 1/4" on the end to project over the edge and with the flat end of the mallet bend it over the edge, as shown in Fig. 15, until it is about the same as shown in the drawing, Fig. 13, being careful that the turned-over end is at right angles to the sides.
Fig'. 13. Construction of blotters and desk-pad corner.
Fig. 14. Blotters.
Then proceed to color and finish in the following manner: Clean well and polish bright with a piece of old emery cloth, wire brush, or, better still, with No. 2 steel wool, which may be procured in ten-cent rolls at the hardware stores. Remember, when coloring with heat in this manner, never to allow the fingers to touch the polished surface; whenever it is necessary to handle it, do so with a piece of clean paper, as the finger-marks will show on the finished work.
Now light the Bunsen burner and regulate the flame with the adjuster at the base so that the flame is blue with a small yellow tip. Hold the blotter with the pliers in the flame so that the yellow tip just touches it, passing it slowly in and out of the flame, occasionally changing your hold with the pliers, as the copper will not color under them. After a short time the copper, if it has been polished bright and clean, will change thru the various colors in this order, varying a little under different conditions:
Fig. 15 Bending the end of the blotters.
1. Orange red.
3. Brassy color.
4. Dark red.
5. Deep purple.
The first two colors sometimes come off when the finish is applied, so that the best colors are Nos. 3, 4, 5, 6, and 7. If you hold the copper in the flame too long - that is, beyond the chestnut color - the color will all flake and rub off, so that it is advisable when coloring for the first time to get a small scrap of copper and polish it and color it in the flame, so that you will know more readily when the right color has come. If it happens that the color does not suit you, or you carry it beyond the chestnut color and it flakes off, you can remove all the color and clean the copper by immersing in a solution of one part sulphuric acid and three parts water in a glass or earthen dish. This solution may be used cold, but will work quicker if slightly warm. Allow the copper to remain in the solution ten or fifteen minutes, then remove and rinse off in water, clean and polish with the emery cloth or steel wool, and color again. When using the sulphuric acid solution, care must be taken to allow none to get on the clothing; it will not hurt the hands, providing they are immediately washed off in water. When you have obtained a good color, allow the work to get perfectly cold, handling it as little as possible, and then flow on the banana oil and allow it to dry.
Next, cut a piece of blotting-paper the exact size of the piece of 20-gage spring brass, hold them together and place one end of the brass and paper under one end of the top, and bend and spring the other end under the other end of the top. The brass will take the shape shown in the photographs and drawing. If the ends of the top have been bent over more than 1/4", the brass will be too long and take too sharp a bend; this is easily remedied by making the brass shorter, cutting a little off one end, and the blotter is finished. Remember that we can only color copper by heat; if the blotter top is of brass, color with the verde green or butter of antimony as described in chapter VIII (Etching, Soft Soldering).
If the students have access to woodworking tools, at school or elsewhere, a wooden block may be prepared with a curved surface to support the blotting-paper instead of the spring brass. The flower design in Fig. 13 is one that might be used with 18-gage soft copper or brass. Punch the holes for the tacks and paint in the design, which in this case may also be on the side as shown in the drawing, and etch while the metal is flat, then bend over the sides with the mallet on the lapping-tool, color and finish. Now make a soft wooden block to fit tight inside of the top and cut the blotting-paper the same width as the wooden block, but 1" longer on each end; fasten these ends to the top of the block with small tacks, being careful to draw the blotting-paper tight. Then squeeze the block into the metal top and fasten it there by driving thru the holes in the sides four copper tacks, which may he bought at almost any hardware store. These blotters might be made more elaborate by making and riveting knobs and handles on the top, making use of the tools and processes described in later chapters.
Fig. 16 Desk set.
Fig. 17 Bending the desk pad corner. No.l.
Fig. 18 Bending the desk-pad corner. No. 2.