Potting compound for building a tank light

[Enderman]

@Tom Tom

You are asking for three different things, which I think need three different materials.

1) Bleed heat out ? I don’t think any sort of encapsulation or potting will help much, more likely to insulate, you need to address the basics first.

2) Waterproof electronics ? This is exactly what conformal coating is for. I don’t understand why is is never mentioned here, it is compulsory for everything that I design.

3) Strengthen weak connectors ? Glue them up with suitable polyurethane or epoxy materials (no, not hot glue). Preferably polyurethane that can be easily cut away if the connector does eventually fail and needs to be replaced.

In summary, potting is not what you need. It’s purpose is primarily to strengthen the device against shock and vibration, secondarily to protect from humidity or other contamination, or, quite commonly, to render the device un-repairable (much more money to be made selling complete assemblies than encouraging simple component replacement) and to make reverse-engineering more difficult.

Which is why most potting compound is black, rather than naturally transparent.

Potting is also an easy consistent way to mass-produce cheap things that might benefit from it,or simply to make them un-repairable. Whereas precise glueing of key components, application of conformal coat, etc. thereby creating a repairable, inspect-able part, is expensive, in skilled labour costs.

Potting does literally those three things.
It is thermally conductive to help cool the electronics, it is waterproof, and it is a solid which strengthens all components against shock and vibration.
Of course there is some potting material which is not thermally conductive, which is why I recommended buying one which is.

You do not need a separate material for separate tasks, this is the year 2018 and humans have evolved a lot.