The Talking Machine Forum — For All Antique Phonographs & Recordings

I was interested in the process of how a metal mold is obtained from a wax master cylinder?

Thanks, Jake

The first step is making the surface of the wax master electrically conductive. Some companies polished the surface with graphite powder. Edison used a different method, called gold sputtering. Gold atoms were transferred from gold leaf foil to the wax surface while in a vacuum. That is why Edison advertised his records as Gold Molded.

The second step was to electroplate the wax master with copper until a shell had been built up.

The third step was to remove the wax master, probably by melting.

I won't go into details of making sub-masters, but this should give you some idea.

Thanks for the response, I was thinking about if the process was feasible for me to complete myself and make resin moulded cylinders, I may attempt to make a mould as I have a nickel plating kit and I could try to plate a recorded cylinder with copper, and make a resin copy.

I wonder if a silicone mould would be a feasible idea?

Thanks, Jake

Jake, I think I would try silicone first. Several people have made and sold replicas from existing cylinder records and I can't imagine any other method to do that without destroying the original. I hope someone that has done it will comment. I expect it is only a matter of testing various silicones and resins to find the optimal materials if they don't tell us. I would also look for a vacuum pump to draw out air bubbles.

Thanks for the advice I will report back within the next couple of weeks, if a good one works, I wonder how a cracked one would fare up I have a copy of 'oh you coon' with a clean split, I wonder how the click will sound on the resin copy of it works.

Thanks, Jake

If the original is cracked, then the copy probably will click, but at least the crack will not grow wider with each sucessive playing as on the original wax it certainly will.

The new cylinders are made from epoxy backed silicone molds. The original method (used during the Blue Amberol era) Originally the surface was coated with PURIFIED graphite and then put in a clamp that had a wire hooked to it, in a copper plating bath with copper anodes, and the master turned and the solution kept circulating through filters. The original master was recorded on a modified Edison Triumph phonograph with a recording had of the trailing kind, (such as I have). Two minute masters cut at 97 1/3tpi for master, mother, working mold method for two minute cylinders, and 194.66666 for four minute masters. Previous to this the Gold Moulded method, the master is put in a vacuum chamber, with two pieces of gold leaf on a mandrel with centers, and it has an iron strap in the mandrel, so the mandrel is magnetic. A large magnet is on the outside of the bell jar. A vacuum created, and then the magnet, is connected to a motor, and sets the magnet spinning, then an induction coil, similar to a model T coil is hooked to the gold leaf, the current turned on, and the electricity vaporizes the gold, it wants to go from one place to another, however the record is in the way and is sputtered. Making metallic soap gold moulded records was very time consuming and required much equipment. At this time the best mastering cylinders are made by Chuck Richards, and Edisonia uses them to produce many of the masters for their catalogs. The master formula used by Edison company for some later cylinders is a lead stearate montan wax formula.

Thanks borri, I am always very interested in your posts I had read about the process before however it was very vauge. You have shined some new light on this for me, I wonder how many times you could use the silicone mould before it became useless.


Thanks, Jake

They did not need to melt masters out of the master mold. Carefully trimming the non title end on a lathe reveled the non title end of the master, the non title end, the song started in far enough in to facilitae this. The masters were 4 ¾" long) and the mold was put in a cool place, like an ice box, or a cool room and the master shrank longitudinally so you could remove it. They most likely shaved the wax master and used it for another recording. The master mold, was then used to make mother cylinders, and the master mold put in a vault working molds were made from the mother mold and mother cylinders, that were plated to make the working mold were gold moulded commercial record formula without the lamp black, so they were a yellowish, brown wax, and quieter than with the lamp black. The best book to learn about original commercial cylinder production is "The Reproduction of sound" by Henry Seymour. This book has formulas for master wax, diagrams of blank moulds, shows how to vacuum sputter masters, and or use pure graphite and the plating solutions needed. It shows how to make a shaving machine, for both cylinders and discs, how to set up a studio recorder with professional trunnion, and trailing style recorder. The plating clamp for holding wax masters for plating. This book also goes into produciton of masters for both vertical and lateral disc recording, and diagrams of vertical, and lateral recorders, horn placement, room acoustics, horn choice ,diaphragm choice, ect. If you send Gerald Fabris a request, via email, he will send you a link to download a pdf file of this book, one of the few books on acoustical sound recording.

How would I find Gerald Fabri email? Again your post always fascinate me.

Thanks, Jake