plating, anodizing, & finishing Q&As since 1989
Etching primer required for painting standard electro-plated EMT conduit?
April 28, 2012
Q. I've searched the forums and seen lots of confirmation of the need for an etching primer for hot dip galvanized metal. But is an etching primer necessary for painting standard thin wall EMT conduit that has a light electro-galvanized finish? I found a Rustoleum spray paint that advertised itself as a "bare metal primer", but it is not an "etching primer". The application is for some homemade frames for a small solar panel array. The panels have a 25 year lifespan, so I'd like to have the painted conduit last as long as possible. I don't mind repainting or replacing the frames in 10 years, but I'd rather not have to do it more than necessary. Thanks in advance for any advice.Jason Tomlinson
Homeowner - Franklin, Tennessee, USA
A. Hi Jason.
I think the etching primer is a very good idea. Some etching primers are available as spray paint.
if you feel that that is more practical than brushing. If you go the other way, you won't be able to prove me wrong for 10 years :-)
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
! Thanks for the tip. I've read several of your informative posts, so I'm not about to go out on a limb against your advice. I'll go the etching primer spray paint route.
- Franklin, Tennessee, USA