I was thinking of painting a copper plate with, maybe black spray paint and leave it under the sun, will the copper plate heat up faster than without black paint?
How efficient will the heat transfer of paint to the copper?
What is the best kind paint to be used?

Part of this depends on the state of the copper. If it's polished and the surface is flat, it is very reflective. But a rough, oxidized surface can have an emissivity that's quite large, meaning it acts more like a blackbody. It also depends on the properties at different wavelengths

https://www.flukeprocessinstruments.com/en-us/service-and-support/knowledge-center/infrared-technology/emissivity-metals

Assuming it's shiny copper, if you paint it, it should be a matte finish, since a glossy one would reflect more light. That will probably heat up faster than just the copper.

Maybe you do an experiment and see how it heats up before and after painting?

This would also depend on how thick and heat conductive the paint is. A thinner coat would be better as the copper is more conductive.

1 hour ago, swansont said:

Part of this depends on the state of the copper. If it's polished and the surface is flat, it is very reflective. But a rough, oxidized surface can have an emissivity that's quite large, meaning it acts more like a blackbody. It also depends on the properties at different wavelengths

https://www.flukeprocessinstruments.com/en-us/service-and-support/knowledge-center/infrared-technology/emissivity-metals

Assuming it's shiny copper, if you paint it, it should be a matte finish, since a glossy one would reflect more light. That will probably heat up faster than just the copper.

Maybe you do an experiment and see how it heats up before and after painting?

thank you very much

Almost anything painted matte black will heat up faster than if left with a shiny/colored surface.
Black will absorb more of the incident radiation, while shiny or colored will reflect some.

However, copper is also very conductive, which means heat will be carried away to all exterior surfaces quickly, and re-radiate.
There is also the matter of the paint/copper interface, and how conductive it is.
( IIRC, copper needs a zinc based primer for paint adhesion, which further complicates matters )

So you asked a very vague question, to which no one can give an exact answer.
I suggest redefining the parameters of your question, or simply trying the experiment with those you have in mind.
Also keep in mind that the intended use comes into play; is it for heat storage, or removal ?

Depending on circumstances, the best bet might be to heat the copper so that it oxidises slightly.
Copper (II) oxide is black and, because it is formed on the surface of the metal it should carry heat to it well.

 

2 hours ago, MigL said:

Almost anything painted matte black will heat up faster than if left with a shiny/colored surface.
Black will absorb more of the incident radiation, while shiny or colored will reflect some.

However, copper is also very conductive, which means heat will be carried away to all exterior surfaces quickly, and re-radiate.
There is also the matter of the paint/copper interface, and how conductive it is.
( IIRC, copper needs a zinc based primer for paint adhesion, which further complicates matters )

So you asked a very vague question, to which no one can give an exact answer.
I suggest redefining the parameters of your question, or simply trying the experiment with those you have in mind.
Also keep in mind that the intended use comes into play; is it for heat storage, or removal ?

heat collection then heat transfer. I asked a mostly general question as I intend to just modify either values to reach a goal of which to absorb heat faster and transfer it somewhere, preferrably with copper heat pipes

2 hours ago, John Cuthber said:

Depending on circumstances, the best bet might be to heat the copper so that it oxidises slightly.
Copper (II) oxide is black and, because it is formed on the surface of the metal it should carry heat to it well.

 

thank you, tho will I be able to use Copper (II) Oxide as paint or will it work (oxidize) on any copper plate?

Edited October 26, 20205 yr by DARK0717

Heat the copper in air and it will oxidise.

34 minutes ago, John Cuthber said:

Heat the copper in air and it will oxidise.

Thank you