Any experience with DIY infills?

[karljs]

I've been thinking a lot about the inconvenience of group buys for getting nice-looking two-tone keycaps.  Has anybody tried getting engraved keycaps (from WASD, or wherever) and doing their own colored infill?

I'm sure I'm not the first to try this, but I couldn't find any old threads.  Any thoughts on the best material to use, or tips for keeping things neat would be greatly appreciated.

[jeroplane]

Feng was selling some with a Cherry logo done by Chaos. Quite an interesting technique if you can get it right, although it seems like it would work best on thicker engraved keys.

[karljs]

Thanks for that link.  I agree about the thicker engraving, too.  It looks like the really thin engraving makes getting smooth lines difficult.

Does anyone know what material Chaos used to fill those?