How do you do it?

[jonson]

heating

David look at Watlow.com or Watlow.co.uk. I have a couple of their flexible silicone rubber heating elements and not too expensive. Very controlable wrap around heat. They do also make a specific heater for heating rubber molds.

[David Schwab]

Thanks! I'll check into that.

[Joe Gwinn]

Initially I was going to make molds and cast my pickups, but the shielding method I use now would be too cumbersome trying to fit in a mold without it touching the sides. Just potting them with epoxy is tricky enough!

One classic dodge would be to dip-coat the assembly to be potted, putting enough layers on that nothing will show through when the dipped assembly is potted.

Another dodge is to make spacers out of the potting material, so when potted the spacers vanish.