Anyone else here have a handcranker?

Devoted to discussion of all-acoustic record-playing machines, such as Edison cylinder players, Victrolas, Brunswick Ultonas, and the like. When the Big Blackout happens, this will be the only audio evidence of our civilization (as it is).

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emorritt
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Location: Tennessee

Pressing

Post: # 1062Unread post emorritt
Tue Feb 27, 2007 6:34 pm

Actually, I have set up a home nickel and copper plating operation, but it was for restoring the metal work on old phonographs. There's a company online that sells everything you need for just about any process you want. http://www.caswellplating.com

It would probably be *possible* to create metal parts with such a setup, but the critical step of making any blank conductive by sputtering would be difficult and somewhat dangerous. The electrodeposition process used voltages upward of 20,000 volts; I assume there's a more modern way of doing it, but I don't know how it works. This gives a clean, even coating of silver (or other conductive metal) to the surface of the grooves that allows plating up a master (metal negative). The old way of dealing with wax was to brush powdered graphite into the grooves then dump the wax blank into a plating bath to create the master. The granules of the graphite added surface noise, and I don't think it would be possible to get graphite to stick well enough to a lacquer disc. The critical part of plating up a master from any original recording is to keep it moving in the plating bath. There's a film by Milton Cross from the 1940's showing how it was done in days of yore, and I'm sure there are a lot of improvements in the modern process (I've never seen a modern disc plating plant).

For home-baked purposes, I'm saying with the materials sold by Caswell it's probably possible, but difficult. It would probably be easier (and cheaper) to come up with some kind of pressing device and just have the metal parts made by a pro outfit.

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kd88
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Post: # 1064Unread post kd88
Thu Mar 01, 2007 1:53 pm

I been busy with a show, so slow to get back to this glorious topic.

I saw the Milton Cross film. That's what gave me the idea about using the wax instead of a lacquer.

I completely agree about the plating process being not really suited for a basement operation. This is a high current, high voltage industrial process and I'm not sure you could pull it off with mains voltage. (You'll be cannibalizing that clothes dryer, fer sure!)

The pouring wax into a flat pan to make a master wax looked doable.

But I ran into difficulties. The difficulty is getting the wax plate to be perfectly smooth and flat. I had better results waxing a paper circle than I did pouring wax into a mold and making a pancake. The problem is the mold: stainless steel burner covers are not perfectly flat to start with, and when you heat them they bow out. The same is true of cake pans. Never bothered me when making a cake, but the cutting stylus bounces over every imperfection, and that is not good. It is also difficult to get a pancake thin enough to be within the cutter's tolerances, yet can be actually handled enough to be set on a turntable.

Turns out that those metal molds shown at RCA in the Cross film are also precision industrial items.

When time permits, I'm going to try
-making a mold in latex with a circular mirror, and
-using the mirror itself to make a mold.

My products from Smooth-On arrived. I found a shadow box that's 12x12x2, so I don't have to do any carpentry. I think I'm going to try reproducing a lacquer. I've got one that I cut on the Presto that had a blemish. (When you buy Dubs, you're not buying Masters!)

I'm up for any suggestions, of course...
kay dee 88

"a warm tube and soft wax..."

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emorritt
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Location: Tennessee

wax masters

Post: # 1071Unread post emorritt
Sat Mar 03, 2007 11:03 pm

The problem you're going to run into using pans or plates for backing is exactly that - their "flimsyness". If you noticed in the Cross film, RCA was using metal plates about 1/4 to 3/8 inches thick, with the center hole already punched, and also pre-heated. The wax material was similar in formula to what Edison used for the original wax 4 minute amberol records before they were made from celluloid.

You would have to make a metal plate and mill the surface completely flat and smooth, and punch a hole on dead center. If you can find a broken wax amberol (DON'T melt a good playable one!!) melt it to about 300 - 400 degrees, and heat the plate up as well - not as hot as the wax but warm enough that it will flow well. This was the "secret" to forming a consistent, smooth recording surface. Only use enough wax to coat the surface. Also, use a pin or a thin blade to remove any pock marks, bubbles, or pinholes that form on the surface. Then, as in the Cross film, you have to cover it up and S-L-O-W-L-Y cool everything. This is also a "secret" - the slow cooling prevents cupping and bowing as you've experienced pouring just a slab of wax. Finally, the flame play across the surface smooths out any minor imperfections, and the blank is ready to be cut.


The dangerous part of the plating process I was referring to was the initial metalizing of the recorded surface of the blank. This is commonly called electrodeposition or more commonly "sputtering". The way I know of doing it requires several kilovolts (thousands of volts) and an evacuated (vacuum) chamber. The power used to make the actual plate is pretty low, and usually batteries or a low power mains transformer can be used (plain old 'D' cells work - I've plated many phonograph parts with them with beautiful results). More power would probably be required for something as large as a 10 or 12 inch disc. The size and surface area of what you're plating is what determines the voltage and current. Too much, and you get a 'burnt' looking artifact. Too little and the plate will be uneven and weak, or you get no plate at all. It takes some experimentation to get the right current and temperature of the plating solution (yes, it has to be heated too). Cold solution produces a dull looking plate, warm produces nice shiny smooth plates.

If I were trying to do something like this at home, I'd be more inclined to use a lacquer for starters. It's probably possible to set up a sputtering rig of some sort, but I'm not really sure how short of using a tesla coil or something like it. The plating could be done with an electric motor and belt rig to keep the blank turning in the solution, and given the right power, solution temp, etc. you'd most likely get something that you could probably press with. Commercial record presses are rated at several thousand pounds of force, so as far as the press goes, I dunno.

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Bratwurst
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Post: # 2390Unread post Bratwurst
Sat Mar 08, 2008 1:57 am

Common neon sign transformers provide up to 15,000 Vac at 60mA. Most sign companies will have some that are old they may give up for cheap or even free. The primary uses mains voltage. You can draw a 5" arc with them!

If you need more amperage, you should be able to hook multiple transformers in parallel? This works with batteries, but obviously transformers are different- don't take my word on that one because they are obviously dangerous.

Sorry to contribute to the OT-ness of the thread! :oops:

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JayDC
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Post: # 2400Unread post JayDC
Mon Mar 10, 2008 6:36 am

ummm anyone heard of EN?.. I thinks thats a chemical plating process. No electricity involved, although the chemicals could be dangerous.

read http://en.wikipedia.org/wiki/Electroless_nickel_plating

You will have to research this further.


EDIT:
After reading the caswell site, I think this product would be the best to a DIY metal project.

http://www.caswellplating.com/kits/silvaspray.html

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agfamatic
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Post: # 10156Unread post agfamatic
Sat Aug 07, 2010 7:49 pm

i have a old Columbia portable from the 1930s. it dosent have its original soundbox but it came with a HMV no 5 b orthophonic soundbox witch sounds great.

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