Molding Cylinder Records

[phonogfp]

“On This Day in the History of Recorded Sound…”

October 1, 1901: Walter Miller and Jonas Aylsworth were granted a U.S. patent (No.683,615) for “Method of Duplicating Phonographic Records.” This important process would allow for the appearance of Edison molded cylinder records in January 1902.

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[Marco Gilardetti]

Many times I've read about this process, but there never was a line about how it was practically made. Is there anyone who can explain in few words what the trick is?

I can't think to anything else than a mold with two halves, but I suppose the problem would be the joins of the halves, which would almost surely return a "click" during playback. The patent images seem to give no real clue about how this issue had been circumvented.

[CarlosV]

Many times I've read about this process, but there never was a line about how it was practically made. Is there anyone who can explain in few words what the trick is?

Marco, my understanding is that the mold was in a single piece. The process relied on controlled heating and shrinkage: the molten wax (actually it was a soap, not wax) was poured in the oversized mold, and let shrink as it cooled down and could then be removed from the mold. The key factor in the process is that the cylinder is not actually a cylinder, but a truncated cone, so it could slip out of the mold by its shorter diameter end. This asymmetry was object of various patent fights between Edison and Lambert, as Lambert also made *conical cylinders* (an oximoron) to fit Edison machines (Edison lost). This fight is described in the interesting book From Tinfoil to Stereo, originally written in the 50s. I have a reprint from1994.

[vintagetenor]

There is a Columbia 2-minute cylinder mold available in Kurt Nauck's current auction.

[Marco Gilardetti]

Thanks for the very understandable answer, Carlos! Ingenious process, and quite difficult to fine-tune precisely I suppose.

I now wonder if from that point onwards, cylinders were always duplicated that way until their commercial demise. Their long-time gauge stability seems a point of concern.

[CarlosV]

I now wonder if from that point onwards, cylinders were always duplicated that way until their commercial demise. Their long-time gauge stability seems a point of concern.

In the USA, I believe all cylinders were produced that way, but Pathé in France duplicated them using pantographs, which explains the low quality of their sound. The long term gauge instability that you mention is more pronounced in the Indestructibles, that were made of a plastic material with a cardboard core, held in shape with metal rings at each end. They tend to shrink longitudinally over the years, causing slips when played. The Edison Blue Amberols, with celluloid playing surface and plaster core, are more stable, but if subject to high thermal excursions, they can also crack along the longitudinal direction, and become unplayable. They also suffer from the long term sublimation of the camphor that is in the celluloid, which eventually will render all of them useless, hopefully not before another 100 years or so. The fact is that none of these products were designed to survive for a long time, and it is somewhat surprising that we can still enjoy these media one century after they were produced. Artistically and commercially, 99% of what was recorded would not survive for longer than some months after their release, so there was not reason to put them in media that would outlast their commercial lives.

[Governor Flyball]

The Pathé process was to record on an outsized cylinder and from this to pantograph copy to respective cylinder and disc formats. The cylinders would be moulded as per Edison and discs pressed as per Victor or Columbia processes.