Curious…
Can a permanent ink felt marker (marks-a-lot, sharpie…etc) be used to color copper and make it an effective black body radiator?
thanks in advance
Not really… paint is a no-no, it acts like an insulator. A marker might be better, but you really want to do a black oxide treatment to improve emissivity. Also, high emissivity and shiny don’t get along. The heatsinks in my 180,000 lumen array were milled out of copper billet, chemically etched to roughen the surface, and heat treated for the oxide layer. (The first ones were anodized aluminum, but finally went with copper). Actually the emissivity of plain copper and black oxide copper is not that much different… you might not want to go to the effort.
Beware of most copper heatsinks. They are more for looks than anything. The fins are usually attached with solder, which kind of ruins the reason for using copper in the first place.
id say yes even though i haven’t tried it
i was looking for aluminum but checked the site and found the above
from this post
also have no idea on reduced heat dissipation but probably not a big concern as it is much lighter than paint
Paint does not act as an insulator on metals, that is not a concern.
I’ve brought this up before, but it is worth reading
Heat emitting/conducting colors
“All colors of clothes and all colors of paint are black in the infrared; they absorb and emit quite nicely.”
Don’t get caught up in the color when it comes to heat emission, we are talking about colors in the infrared spectrum, not the paint color spectrum.
Absolutely not… I have equipment that can see down below 10 microns (thermal IR) to well past UV. All paints and clothes are not created equal. And I have done thermal imaging on heatsink surface temperatures and paints can definitely make things worse.
Birch Black or Blue Coat works well but offers no thermal or protective value. I would use it
only if im touching up Blue Coat…
Some of you are familiar with Cerakote? A few vendors offer the coating service over at CPF, i had a C2 finished in white Cerakote . I just found an easy DIY Cerakote kit from the manufacturer. Includes everything you need and it doesn’t require anything you wouldn’t have in a kitchen. Thermal value is excellent and if you follow directions with meticulous prep the end result is a professional finish with excellent thermal dissipation. I have a few copper heat sinks coated with a clear and headers with Cerakote
Good general introduction to the concept — it’s called “emissivity” — along with links to information about various materials — start here: https://www.energystar.gov/index.cfm?c=roof_prods.pr_roof_emissivity
and these are helpful: paint emissivity at DuckDuckGo
from that search, this page: Black matte paint for space use
has, just as one example, this answer, among much else:
“A. The emissivity of Krylon Ultra Flat Black Paint is listed in the web site below as 0.97 at 5 um…… I sprayed the paint on a copper plate and …. measured an emissivity …. for the black paint of ~0.97 in agreement with the web site.
http://www.infrared-thermography.com/training.htm
James R. Lindle
Research Physicist - Bowie, Maryland”