DA wrote:

The question naturally arose: "what paint to use?"
...
There won't be any actual steam there (compressed air)

Good Grief! Unbunch your panties, go to any autoparts (Pep boys, Kraken)
or home improvement store or any hobby shop, and just get any ol' paint!
OK, not "Any ol' paint" - probably not latex wall paint, but some kind of
enamel. If it's not going to be subjected to any abuse, even lacquer would
work.

Just be sure the parts are clean and you follow the label instructions
on the paint itself, and you'll be fine.

Some may recommend zinc chromate primer; I won't argue with them, but
it's probably not necessary, although it might make you feel more
comfortable with your paint job on your new toy. :-)

Have Fun!
Rich