AN EXPERIMENT IN ELECTROFORMING*
I had been serving as printer's devil in an amateur printshop and had been initiated into all the intricate operations of setting up type and distributing "pie." Naturally, I became very much interested in the process of electrotyping when this subject was touched upon in the chemistry course. Readine material on the process was not overabundant but, once I had begun, I learned by experience. I n this article I will describe how I made an electrotype. I think that statuettes, medallions, engravings, and embossing~ could be reproduced just as easily and in a similar manner. Electroformiug can serve as an excellent laboratory experiment to illustrate Faraday's law, ionization, and the fundamental principles of electrochemistry. Forming the Impression
I melted a mixture of beeswax and "Gallica" wax, and added to it about one-sixth of its volume of finely powdered. graphite. ON WAX IMPRESSION FROM ELECTROTYPE FORMED I made a shallow tin box PRINTER'S TYPE about eight inches square and one inch deep and in this I cast a slab of the wax mixture, embedding in its center a sheet of copper foil. This was later to carry the cathode current. It was of slightly smaller area than the wax slab itself and had a projecting lug for connection. When the wax had solidified, the metal box was readily stripped off. I rubbed into the smooth upper surface of the wax a small amount of powdered graphite until it was well coated and presented a polished appearance. I: was now ready to receive the impression of the type-form which was to he electrotyped. To secure the necessary pressure I used a small letter press, placing the chase with the type upon its base, and laying over i t the slab of wax which had been *Winner of ten-dollar award in the student contest closing March 15, 1928.
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warmed until suffraently soft. Pressure was then applied until the impression was sufficiently deep. I found this to be the most delicate part of the whole process for if too much pressure is applied an imperfect or cracked impression results. Lifting the wax "matrix" from the type form presented no difficulty, and, as I had worked carefully, I was rewarded with a perfect impression. Even minute indentations and delicate lines were reproduced faithfully. heparing a Plating Surface
I found it to be essential to success that the entire surface to be plated be rendered conductive by thoroughly coating it with powdered graphite. On a large, smooth surface, I did this with the fingers, rubbing until a slick, glossy finish was secured. To graphitize corners, fine indentations, and irregular lines, such as occur in an impression of a page of type, I made a graphitizing brush of original design. It consisted mainly of a piece of rubber tubing about a foot long, which was made to serve as a flexible shaft. One end of the tubing was attached to the shaft of a partly dismantled tool grinder, and the other to a camel's hair brush. The brush turned loosely in a short piece of brass tubing which could be held in the hand. The revolving brush easily worked the graphite into otherwise inaccessible places. To make electrical contact with the prepared surface, I drove a few small nails into the imbedded sheet of copper foil mentioned above, so that their heads made contact with the graphite surface. Plating My plating tank consisted of a large, oblong battery jar. This I filled with a plating solution made by dissolving twenty ounces of copper sulfate in a gallon of water made strongly acid with sulfuric acid. For anodes I used pieces of old copper roofing; almost any scrap copper will do. The prepared wax constituted the cathode. After making sure that all the
cavities in the surface of the wax were "wet" with the solution, I hung the anode copper about two inches from the wax. The current was obtained from two cells of a storage battery and so regulated with a rheostat that only 0.3 to 0.4 ampere per fifty square inches of plating surface flowed through the bath. I regulated the deposition carefully so that the deposited copper would be bright and not too roughly crystalline. Finishing After about twenty-four hours of plating, I secured a fairly heavy deposit. Taking the electrotype from the bath, I stripped it from the wax and placed it under water to minimize oxidation of its surface, until I was ready to back it up. I did this with melted type metal, using soldering flux to make the metals adhere. The type metal gives the copper shell strength and rigidity. I mounted the cleaned electrotype upon a block of wood "type-high" and then it was ready for printing. The illustrations show some of the work I have succeeded in electroforming. The first is a photograph PROOFPRINTCD F R O M HALF-TONE of the electrotype herein described. I)UPLICATE The second shows the duplicate of a "half-tone" plate made subsequently. A proof printed therefrom is also shown. The field of electroforming is full of opportunity for the ingenious experimenter. A neat embossing, reproduced in copper, lacquered and framed, presents a very artistic appearance and makes an ideal gift. For one who would wish to do more, the reproduction from plaster or gelatin casts of carved busts or statuettes would furnish matter for a very enjoyable and profitable hobby. For me it was an experiment that greatly increased my interest in chemistry and stimulated me to further study.
