Depends on the water quality and what type of galvanized piping was used
Metal LENOX
"Drywall primer" -Yes, -it's called exactly that -right on the can !
percussion
No. Galvanized pipe is what they used to use, and now should either be replaced with modern type of water pipe such as PEX or copper. COMMENT: Complete agreement. Galvanized served it's purpose and did bring water into a lot of people's homes for a lot of years. That was then, this is now. Today, it would be a dead last choice for a plumbing system.
As long as the surface is clean and dull, then either an oil or acrylic primer can be used to cover oil-based paints.
1 1/2"-2 1/2" 8d galvanized finish nail. length depends on thickness of item you're securing
Pvc, Wirsbo, Copper, galvenized, pex, or Polyethylene
I would sand it down with sand paper then paint with primer. After that apply a outdoor paint. Prep work should be smooth If you really want it to be nice hit the primer with a light sandpaper after the primer coat.
Drywall primer should be used.
If the primer was a water based primer, then you are in trouble. If it was, then you need to strip it down to the metal and use either an oil based primer or I would use a primer made by Rustoleum.
Yes, the kind you use for duct work.