What about powder coating Nick? Have you been down that road at all? Perhaps too costly to bother?
Hi Ben
Most cost effective finish is hammertone paint. If you use the silver/grey colour it will give that cheap chinese mic a real vintage look.
Best part about hammertone paint is, if you get a chip in the paint, it's very easy to touch up.
It's available in spray packs and brush on.
I use the brush on variety and add a little
Penetrol to it. It improves the the paints ability to bond to the metal.
Penetrol is also excellent for refurbishing old vintage gear that's been affected by rust.
1: Get rid of any flaky rust and surface rust,
2: Give it a light sand and make sure the metalwork is clean and dry.
3: Apply the Pentrol as a primer. This will neutralise the rust and give you a solid surface to paint on.
4: Allow 24 hours for the Penetrol to dry then apply 2-3 coats of hammertone paint and that old rusty enclosure will look like the day it left the factory.
Because the hammertone paint has a motley finish it hides a lot of imperfections in the metalwork.
The bad news... Penetrol is expensive... but like Vegemite or Tabasco sauce, a little bit goes a long way.
If your a serious DIY'er then Penetrol and hammertone paint will be your friend for life. Ideal for all those projects where you're buiding FX pedals, DI box's, pre's etc.
Penetrol and hammertone paint are available at most large hardware stores... Bunnings, Mitre 10, etc
The hammertone paint I use is made by White Knight and called Rust Guard - Hammered Finish
But I digress... getting back to mic... make sure you you wipe it down with white spirits before painting to remove any protective oily coating that's been applied to it. Then give it a light sand with a very fine emery paper.
Finally, don't paint the top and bottom edges of the casing or the bottom of the inside rim of the securing ring, as you want to maintain continuity of earthing thru the entire casing.
Oh yeah... Don't paint the headbasket... Doh!
That's the way I'd finish the mic.
Hope this helps.