Exhibition Reproducer colors

[WDC]

As disc machines aren't really my expertise I'd thought to ask around here as I am sure someone can tell me almost right away.

The later gold-plated exhibition reproducers have a very distinctive copper-plate behind the diaphragm. But I keep asking myself over and over what is nature of the black tint found on the earlier Exhibitons?

The only one I have is a long throat, where's practically impossible for me to tell what the original color might have been. This does also count for the back piece, which seems to have been somewhat black too. Were these originally painted or coated? Does this also include the bar and needle assembly?

Thanks in advance to anyone who may answer!

[Henry]

I always assumed that the body of the Exhibition is brass. I have just confirmed that it is not ferrous metal, as it does not attract a magnet ("it" meaning the nickel-plated front ring and the blackened-brass rear element). The machine screws, needle bar, and adjustable parts ancillary to the needle bar are magnetic, however. There is a way to chemically blacken brass; a product (name escapes me) known to model railroaders that does just that, but what its chemical composition is I do not know. I believe that this topic has come up on the board in the past, so a search might turn up something relevant.

[Orthophonic]

As far as I know, most were chemically blackened except for some gold colored ones.

[gramophoneshane]

This should be helpful.

http://www.nostalgiaair.org/references/ ... lash05.htm

[WDC]

Thanks a lot for the helpful posts. This does finally solve a mystery to me. It never looked really like a coating, but a chemically blackened surface explains it all.

Quite interesting how to persue the total opposite of what I usually would do with an old metal piece.