What were 78s made of? - Part 2

  • Continuing from my last post, I'm adding further info from the 78-L list regarding 78rpm record manufacture. In review of the discussion notes, it would be fair to assume that Edison spent some time developing compounds for the ideal cylinder (as he saw disc recordings as inferior - even though he later stopped cylinder production for disc by the 1920's).

    A member of the list writes:

    The very earliest (1887-1890) cylinder records used in the Edison Talking Doll and with Edison's 'Improved' and 'Class M' Phonographs were blended wax compounds that proved fragile and difficult to record upon due to atmospheric changes in those pre-HVAC days, and were subject to extreme wear upon playback. After 1890. research was begun on using non-lathering metallic soap compounds (i.e., zinc, lead, tin stearates) to make cylinders. These early cylinders were highly acidic and tended to foul the iron cutting stylii by rusting them almost immediately. They also tended to cloud over overnight on their surface with a chemical glaze that was difficult to cut through and caused greater surface noise upon playback. I have heard that these cylinders smelled much like strong cigar tobacco. These problems were largely solved by the collaborative work of Thomas Hood Macdonald (chief engineer of American Graphophone) and Adolph Melzer (and his brother), soap chemists of Evansville, Indiana contracted by Macdonald. Also 1886-1895 (at the very latest), were the 1-5/16"x6" constant-bore thin cardboard cylinders developed by Chichester Bell and Charles Sumner Tainter for their invention, the Graphophone. These cylinders were thinly coated with an ozocerite was and unlike Edison's much thicker solid 'wax' cylinders, were not shaveable and re-recordable. These were rendered obsolete very quickly by Edison's format and many Graphophones were converted to accept Edison's cylinder with the addition of a tapered-bore removable mandrel. Molded celluloid cylinders were first developed in a proprietary format by Lioret in France, and then independently by Philpot in England and/with Lambert in the US (1900). Lambert cylinders have no cardboard core -- they are completely thin celluloid and only contact the mandrel on the ends. Varian Harris in the US also developed molded celluloid cylinders, and these do have thicker cardboard cores. The subject of molded celluloid cylinders is a subject all to itself! In 1902, Edison produced molded cylinders in metallic soap. These are the relatively ubiquitous cylinders commonly called "black wax" by collectors today. While the soap compound that these are made from (developed by Edison's chemist Jonas Aylesworth) is harder than previous formulations (since shaving and recording was not applicable), the real neccesity of the formulation is a predictable shrinkage rate, since the hot soap when injected into the mold, must shrink the depth of the groove plus a little more when the mold is chilled in order for the record to drop cleanly from the mold. The introduction of four-minute wax Amberols in late 1908 required an even harder soap to hold the walls of the fine 200tpi groove. This harder soap resulted, unfortunately, in a much more brittle record!

    But as an interesting end note to this US-centric focus on what 78s were made of, I reproduce what Steven Barr wrote on the list as a general summation:

    Virtually ALL "78's" were pressed using shellac-based compounds! This is often described by NON-knowledgeable people (usually eBay sellers!) as "bakelite." A handful of 78's were pressed on vinyl-based compounds during the early thirties, due to the effect of the war on shellac production (and as well to provide quieter records for radio airplay!) It is very possible that what the writer here describes as "recording cylinders" were, in fact, the cylinders intended for "Dictaphone" use? OTOH, it seems to me that if there were made of Bakelite, they would have been MUCH harder to record...?!

    I hope to follow this post up with a further analysis of 78-L discussions relating to record production in the UK and Europe soon...

Comments

0 comments