@Douglass: ...For the brass, of course there's Jake von Slatt's Steampunk Workshop site...
I LOVE that synthesizer -- I keep on going back and forth with regard to etching scroll work and words onto the brass plates ... I'm going to bounce over to Jake's site to take a look at what he has to say...
@David: Love the bobbly toggle switch...but what is the copper thingy above it?
The bobbly switches are really tasty, but from the front you will see the nuts used to attach them to the panel -- I'm hoping to use the copper dome things (with slots milled in them to accomodate the movement of the switches armatures) to hide the nuts and add more visual interest.
Max: It's looking great so far... and those motorized potentiometers look like they'll be really handy for something like this, for a sort of mind-of-it's-own effect.
I've usually found that the lettering on buttons of that type of assembly turn out to be embedded at least deeply enough to make any attempt to remove them turn out rather messy. You can try polishing them off... but if that doesn't work, you might still be able to buy sets of old typewriter keys on ebay as a substitute.
Alternatively, crafting stores ( like Michaels ) used to handle alphabetized buttons ( "charms" or "eyelets" ) made of pewter, from which I've had some small measure of success at creating faux typewriter keys and pushbuttons ( combining them with hardwood plugs ( Lowes ) and brass lamp-check rings ).
For the brass, of course there's Jake von Slatt's Steampunk Workshop site, at which he has documented methods in etching brass for antiquing effects. Some other folks have used his methods to get great results, such as this "Steampunk Synthesizer":
That font I mentioned in the Part 1 comments is called "ws_simple_gallifreyan", ( a zipped .ttf file ) and is available at several sites. It's very basic, but can be put to very good effect if you use it as a manipulatable font in an image-editing program. Rotating, varying the font size, and moving letters as individual "objects" on your background, combined with other effects such as "find-edges" and "emboss" can eventually produce some decent looking script... that would probably look even better when etched into brass.
Years ago I read how they used a sandblasting pen (turned way down) to clean the Dead Sea Scrolls. Here is on example of a micro-sandblaster (http://www.scmsysteminc.com/sandblasting.php ) although I don't know where you might borrow one.
Max...those motorised pots are very nice....I tried to get a couple recently when a supplier had them on special, but they had sold out :-(
Love the bobbly toggle switch...but what is the copper thingy above it?
For your telephone switches you could try a brass polish to get rid of the letters. The stuff we have here is called (strangely) Brasso. It's very mildly abrasive (so will remove scratches etc and probably paint) but very finely so, so it will give a nice finish. I have used it for removing scratches from meter faces. You may need to use very fine emery paper first (600 or better).
Here's another possibility -- starting from the center position (which now reflects something like "neither here nor there"), all of the LEDs are dimmer versions oftheir main colors. If we rotate the knob anticlockwise, more and more green LEDs come up to full brightness (top image), by comparison, if we rotate the knob clockwise, more and more RED leds come to full brightness. In this case, maybe the top center LED should fully on with an in-between color when the knob is pointing fully upwards, then it turns red or green depending on which way the knob is being rotated...