Another question : can you paint (spraypaint) such a light or does it harm the thermal capacity of the copper?
I would like to paint it to make it look nicer.
Thx
Can you paint it? Yes.
Will it affect thermal transfer to the air? Yes. Not a huge effect though.
It will not affect thermal transfer inside the light from the LED to the copper under the paint. As I understand it, unless you use a thick insulating layer of paint it has a minor effect, the order of best heat trasmission to air is (from my reading and I do not remember seeing actual numbers attached):
Anodized aluminum
Aluminum
Copper
Paint
The differences in the top three are small and overshadowed by the small changes in the size of the sink, ambient temperature, or air speed over the light. I would think that a thin layer of aluimum paint (has metal in it) should be better than flat black paint (radiates heat well think stoves), should be better than say a thick coating of white enamel or epoxy.
3 options other than paint:
1. Make the light with aluminum electrical conduit or similar pipe. There is a thread of an aluminum CuLite on MTBr somewhere. You can opt for a brushed finish, polish it to a mirror finish, or spend the money to anodize it (another thread on that in MTBr). If weight is an issue for you this is a great option if you want a light body to match other components. Warning: anodizing apparently is as addictive as making lights.
2. Make the light bigger so it has more area in contact with the air to compensate for the paint. Longer helps the O ring mounting method too.
3. Polish the copper regularly to keep that bright gold-orange color not the dull burnt orange to bronze it will tarnish to. A little oil or wax after the polishing (residual in most polishing compounds) will slow the tarnishing but I am not sure how that compares to a coat of paint. I'd guess a LOT thinner, so negligible.
