I want to introduce myslef to the list.  I am Shawn Borri, from The North American Phonograph Company.  I enjoy casting wax cylinder records, and recording on them.  Some things that might help conservators about the cylinders:
1.  Cylinders to vary in composition. 
A. The first cyinders by Bell  & Tainter, are of a ozocerite, or ozocerite carnuba compoind on a cardboard spiral core. These were the first "Wax" records,  C 1885
B 1887-1888 Edison solid wax cylinders a composition of 25% steric acid, 25% Beeswax, and 50% ceresin wax.
C. Late 1888- early 1889 Edison changed the composition (Actually  Jonas Aylsworth, Chemist) The composition of Aluminum Sterate, or lead stereate, followed by the adittion of sal soda and Ceresin as an emusifier/ moisture barrior. Some of the early Edison wax cylinders made from 1889-1893 used Acetate of Alumina, which to boil out, the wax had to be  cooked at high temps (reaching almost 500 degrees)  to remove the acetic acid.
D.  Sheet aluminum was used in subtitute for Aluminum acetate.  
Experimental Columbia wax cylinders, it an effort to duplicate the Edison formula made a defective metalized soap with lead sterate and ozocerite. It was not untill almost 1895 that Columbia though Adolf Melzer came up with a composition similar to the Edison formula.
1901-02 The Edison brown wax fomula, with the addition of zinc and copper salts, and carnuba,lampblack resulted in the greyish hard moulded record composition. Later in 1904 Ebonite replaced carnuba.
1908 the wax amberol compositon, of sterate of litharge and ebonite.
Some observations.  That not all mold is mold on cylinders. Yes some cylinders do get moldy from fungal, and animal bacteria that eats the wax.  Some waxes have oxides and oils that surface as a white or blue haze.  One problem with some formulas, was that some of the suppliers, and or mateiral purchasers for Edison and Columbia substituted lower quality steric acid into the formula, which after sometime will fog. Most of these records were spotted and pullled, but I am sure some went out.  The cheaper stereic moulds easier, but contains high amounts of olaic, and or glycerin, in time this leaches to the surface of the records. Edison purchased some steric from Proctor and Gambel company and found it not good for record making, and found at the time Mtichels  to be the best.  The difference is in processing, the double pressed, still has oils  and the triple pressed has less.  When you cast a wax cylinder,  the humidity in the room is of great importance, good blanks can  not be cast on  humid days, one reason as the wax cools in the mould the water droplets from the air condence in the wax and is thus trapped in the wax, and is seen as stars and bubbles in the surface. This effect looks like mould, but is not.*** (could it be that some records just may have went by inspection with these defects?)***  Sometimes these do not affect the surface noise, and other times do.   These observations are from my own workings with actually making the metallic sops, and moulding the cylinder blanks.

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