Painted Heat Sinks

[Chris Jones]

That may be good for the written specification, but it is not what you
want for outdoor P.A. gear which may be used in strong sunshine; it will
absorb more radiant energy because of it.

I'm not sure that all polished metals reflect infra-red wavelengths
well, either. I have recollections of 'reflective' car tools getting
very hot when left lying around in the sunshine.

I think you can buy specially coated aluminium from Alanod in Germany, this
metal is "shiny" in the long-wavelength infra-red, but "black" in the
visible and near-infra-red where the sun emits most of its energy. The
intention is that this metal should be laser welded to copper pipes for use
in solar water heaters, hence they want it to absorb sunlight and then not
re-emit the energy. It is the opposite of what you want on your PA
equipment.

Chris

 

[Dave]

Fat! 34 - 22 - 34 will have better longterm reliability.

John

Models with those figures appear to have very low tolerances and are more
prone to (thermal) run-away, best to go for a more stable, slightly
over-engineed model which can take the heat.

 

[Adrian Tuddenham]

Fat! 34 - 22 - 34 will have better longterm reliability.

How about a mermaid: 36 - 24 - 1/6d a pound.

 

[montie]

Evening All

Thanks for everyone's help

The diecast cover I'm making has the following requirements

1) serve as a finned heat sink on the outsid
2) have a selection of colors available (hence the push toward
painting
3) have electrically conductive surfaces on the inside (for EMI/RF
gasketing

The die casting house is telling us that the only colors they ca
anodize (because of the aluminum allow being used) is dirty grey an
black. The client wants something more colorful

Assuming that paint is the answer, the order of operations for th
part is

1) yellow chromate the par
2) mask the areas that need to be electrically conductiv
3) paint the cove

Any suggestions here? At this point we plan to use a powder coa
finish. Any suggestions of paints that are more thermall
conductive

Thanks
Monti