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Edison Phonograph Division Documents

Edison Diamond Disc Manufacturing Processes (1920–29)

By Paul B. Kasakove
Reproduced courtesy of the Edison National Historic Site (West Orange, New Jersey)

Edison Records 1926-29, by Ray Wile

In conjunction with the upcoming release of the first installment in the Edison Discography Series, Mainspring Press is pleased to present selected papers, excerpts, and photographs from the archives of author Raymond Wile and the Edison National Historic Site.

Note: In 1920, with sales of Diamond Discs at an all-time high (see Edison Disc Record and Phonograph Statistics), the Edison factory found it hard to meet demand for the records.
Paul Kasakove was hired to develop new processes that would shorten the disc production cycle. The following are his recollections. Particularly interesting is Kasakove's observation that only one of the usual three takes was chosen for issue, with the other two takes held in reserve for "emergency" use. This refutes the often-repeated (and incorrect) statement that all three takes of any given Edison master were automatically issued.

Edison Diamond Disc Records (Hill and Dale) Manufacturing Processes as of 1920 to 1929 from Wax Masters to Condensite Records

By Paul B. Kasakove (July 1964)


Electroplating Process for Disc Record Moulds

In July 1920, I was engaged by Mr. T. A. Edison to modernize the entire process for making the nickel-faced copper moulds that were used, to press out the disc records. It was taking approximately three weeks from the time the newly recorded Wax Masters were delivered to West Orange from our New York Studio, before the first prints from the Wax Masters could be heard. As a result of the experimental work by Mr. T. A. Edison and myself, the process was changed so that the three-week period mentioned above was reduced to three days. The first disc record made by this improved process is on display in Mr. Edison's library.
This improved process remained in use right up to the tine the Disc Record Manufacturing Division was shut down. It may be described, as follows:

1. The Wax Masters were recorded in our New York Studio and delivered to the plant at West Orange in the evening of the same day that the recordings were made. Mr. Walter Miller, who headed our New York Studio at the time, and who lived in West Orange, would usually bring the Wax Masters in on his way home. It was the practice to make three Wax Master Recordings for each selection, and they were identified by a serial number and the letters A, B, and C.

2. On the morning following the delivery of the Wax Masters, they were turned over to the Plating Department employee who was responsible for the grafiting [sic] operation. This grafiting process, the purpose of which was to provide the recorded face of the Wax Master with an electro conductive surface, had replaced the gold coating process, because it saved a full day's time. At first, the grafite [sic] that was used to coat the wax was purchased: as ordinary commercial grafite, and subjected to an elaborate purification process which consisted of fusing the grafite with caustic soda, then dissolving out all the impurities, rinsing thoroughly in distilled water, with a final rinse in pure grain alcohol. Later I discovered a small company in Connecticut that specialized in making and selling grafite, purified for electroplating purposes, and I vas able to buy this grafite cheaper than I could purify it myself, so we discontinued the purification process. The grafiting of the Wax Masters took only a few minutes. They were placed on & table which could be made to revolve slowly while being brushed with a very fine silk bristle brush saturated with grafite, which just barely touched the face of the Wax Master. At first My Edison was somewhat concerned that this brushing action might result in removing some of the wax, thereby causing poor reproduction. However, I was able to reassure him by letting him listen to and inspect two records of the same selection one made by the old Gold Coating Process, and one by the grafiting process described above. He was unable to see or hear any difference. When the grafiting of the Wax Masters was completed, they were brought down to the Master elating Room located just below the Grafiting Room in the same building, (22A).

3. As soon as the Grafited Wax Masters were received by the man responsible for the copper plating of the masters (Peter Dempsey), he would mount each Wax Master on a suitable, specially designed, plating holder, which permitted the master to be rotated while semi-submerged, in a Copper Plating Bath, with the electric current passing from a Copper Anode in the bath through the Copper Sulfate-Sulfuric Acid solution to the grafited face of the Wax Master, depositing a coat of copper on to the grafited face. It formerly took several days before the deposited copper was heavy enough (about .030") to be stripped from the Wax to be used as the Copper Master. However, we were able to cut this time down to 24 hours or less. As soon as the recorded face of the Wax Master was completely covered with Copper, an operation that took about four or five hours, the Wax Master and holder, were transferred to another bath, which was a cylindrical hard rubber pot containing a more concentrated copper-plating solution, and in this bath, the Wax Master was suspended face down, and completely submerged. In the bottom of the hard rubber pot was a Copper Anode. By increasing the concentration of the Copper Sulfate solution to permit higher current densities, and by rapid circulation of the solution between the plating baths and the central storage tank, the Copper Masters were heavy enough for stripping from the Wax the following morning.

4. When the Copper Master plated to the Wax Master had reached the proper thickness, the plated Wax Master was delivered to Mr. Frank Clancy, Supervisor of the Lathe Department on the 3rd floor of Building 24. Here it was mounted on a Lathe, the outer edge turned down until the line of separation between Wax and Copper became visible, and then the Copper Master was stripped from the Wax. The Wax was returned to the Silver Lake Wax Department for remelting. The Copper Master would have a brass lug soldered in the center of. the back of the mould and returned to the Plating Department.

5. In the Plating Department, the first step was to place the Copper Master face up on a turn-table of a polishing machine, so designed as to permit the turn-table to rotate, while a circular brush, fed with a rouge polishing compound rotated slowly, with the bristles in contact with the face of the Copper Master. Although this polishing operation produced a completely clean surface on the face of the Copper Master, it did not affect adversely the sound reproduction.

6. After polishing, the Copper Master was mounted on a Mould Holder, placed in an electro-cleaning bath (a Sodium Sulfate solution), for about two minutes to insure a chemically clean surface, rinsed in distilled water, and then immersed in the "8-4" solution and rotated for about two minutes. It was then removed; rinsed again in distilled water, and placed immediately, while still wet, in the Nickel Plating Bath.

7. The Nickel Plating operation under the old process required at least ten hours to get the required thickness of coating (about 0.0004"). By increasing the density of the Nickel Plating Solution using Glacial Ascetic Acid to improve conductivity, and immersing the Copper Master in the solution face down instead of semi-submerged as was previously done, and using Nickel Shot for an anode instead of a solid cast anode, the total time required to get the desired thickness of nickel was reduced from ten hours to two hours. The Nickel. Shot was contained in a hard rubber, round, tray at the bottom of the hard rubber cylindrical plating bath, and was periodically removed from the bath and washed free of the Nickel Sludge which is formed during the electroplating process. The sludge was replaced by new Nickel Shot Additional changes made to speed up the Nickel Plating consisted of raising the temperature of the Nickel Solution to about 120°F, and circulating it rapidly between a central storage tank and the individual plating baths. As a result of these various changes, we were able to reduce the plating time from ten hours to two hours. Because of the increased current density, there was a tendency occasionally toward the formation of an excess of Hydrogen gas bubbles to be re- leased, which if allowed to settle on the face of the mould being plated would result in a series of small holes in the plating. To prevent this, we added some hydrogen peroxide, which combined with the excess Hydrogen to form water.

8. After two hours in the Nickel Plating Bath, the Copper Master was removed from the bath, rinsed quickly and thoroughly, and transferred without any delay into the Copper Plating Bath, which was also a cylindrical hard-rubber pot, with a specially designed copper anode at the bottom of the pot. The Copper Master, attached to its Mould Holder, was suspended face down in the Copper Plating Solution in this pot, and rotated rapidly with the current on. The cast copper anodes used for this high speed copper plating process were made in our own copper foundry located in the rear of Building 1, and were so designed as to permit of a maximum surface facing the cathode (master) and also to permit the Copper Sludge which was formed in the plating process to be washed to the bottom of the plating bath by the circulating copper plating solution. The copper plating solution was stored and heated in large crocks from which it was pumped and fed individually to each Copper Plating pot. Since any interruption in the electro-plating before the desired thickness of copper was obtained would spoil the mould, it was necessary to guard against such an interruption by having available at all tines an emergency source of current. This was accomplished by keeping a sufficient number of Edison Nickel-Iron Batteries in a separate room in Building 22A. These batteries were connected in such a manner as to permit of an immediate switch in the event of a power failure. The electroplating process was continuous, 24 hours a day, seven days a week. I was on call at all times in the event that anything went wrong with the process.

9. On the morning following the start of the copper plating of the female to the Copper Master, the Master with its plated female was removed from the Copper Bath and its holder, washed, dried, and delivered to a room adjacent to the plating room. Here a trained lathe operator turned down the beaded copper plated edge, until the line of separation between the nickel face of the female, and the Copper Master, became visible. Then on a machine specially designed by Sam Moore for this purpose the Master and female were separated cleanly, without in any way marring the surface of either one. The time required for making a Female from a Copper Master totaled about 24 hours as compared with a minimum of three days by the old process.

10. The Nickel faced Female Mould, after stripping from the Copper Master, was sent up to Mr. Clancy on the 3rd floor of Building 24 where a brass lug was soldered to the center of the back of the mould, so that it could be screwed to the Mould Holder, and returned to the Plating Department. Here it was given a quick polish similar to that given the Copper Master, but since the Nickel face was so much tougher than the copper face on the Master, the polishing compound in this case consisted of a fine emery paste. After polishing, the female mould was put through the same cycle as the Copper Master, as described above; i.e., Electro-clean, Rinse, Rotate in "8-4" Solution, Rinse, Nickel Plate 2 hours, rinsed and place in Copper Plating Bath until the following morning. It was then removed, the plated mould stripped from the Female, and sent up to Mr. Clancy to be finished to glass-like smoothness on the back, so it could be used to press out the male recording on its nickel face, on to the Disc Record Blanks. This was called the Working Mould, and if properly handled could print several hundred Disc Records.

11. The complete cycle as described above, from the receipt of the Wax Master Recording to the completion of the Working Mould, could be repeated as many times as necessary to print the number of records needed for sales. The Copper Master could produce about ten Females. Each Female could produce at least a dozen Working Moulds, and if by any chance something happened that would interfere with the completion of the number of moulds needed, it was always possible to start with one of the other two Wax Masters kept in the Vault for emergencies.

12. All three Wax Masters on a given selection were put through the above cycle so that at least one print from each Master could be listened to by our Music Committee, of which Mr. Thomas A. Edison was a member, and this Committee chose one of the three for production. However, to insure that nothing happened that would cause any deterioration with the face of the Copper Masters, I arranged that after they were no longer needed for immediate use, they were put through the plating cycle again, but were not separated from the plated female. The Copper Masters with the female mould plated to them for protection were stored in the Vault for possible future use and safe keeping

— Paul B. Kasakov (July 2, 1964)

Document History: Initial posting 5/27/2008.

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