The answer to that question lies in your plumbing!

I thought about your question for ages, trying to think of when I had ever seen painted copper...

Then it dawned on me! I have been painting radiator pipes (on and off) for years with both the old, solvent based, paints and more recently with heat tolerating water based ones and what are radiator pipes made of? Copper!

So, I don't think it will be a problem (It might be a good idea to run it through a meths-soaked rag before using in order to remove any grease - just in case).

Hi, Just a quick suggestion, I’ve painted small copper parts in other projects and the best way that I found to do it to avoid the paint from “lifting” is to first give it a fine spray of grey acrylic primer(I use Vallejo’s) Then go over it with a thinned down (2:1) coat of the colour you want to use. Once dry apply a second coat if necessary.

Enjoy your build, Phil

I would be inclined to wipe the copper wire with a solvent to remove and residues from the manufacturing process, just to be on the safe side. I'd also give the wire a quick rub with some fine wet n dry to give the surface a key to help the paint stick.

I've painted copper wire without problems using the above techniques.

Cheers
Mark