Hot Rod Forum banner

How to remove engine surface rust prior to painting

2K views 9 replies 8 participants last post by  PHWOARchild 
#1 ·
guys,

I had the 390 for the AMX I'm restoring rebuilt six months ago. Despite being in my shop and being primed and covered by an engine bag, it got some surface rust on it. I'm ready to paint it now and wondering what I should use to treat/remove the rust prior to prime/paint.

Thanks,
Mike
 

Attachments

See less See more
3
#6 ·
Metal Prep or Ospho is phosphoric acid. It should be mixed 50-50 with hot water and brushed on the metal surface. Let it set for 30 minutes and wash it off with water. Brush off any residue and paint as soon as the metal is dry.

Phosphric acid is a mild acid and can be used with bare hands. It is even a constituent of Coca Cola.
 
#7 ·
Metal Prep. Use a bit of ScotchBrite soaked in Metal Prep and scrub the rusty surfaces. The rust will disappear very quickly. If there is a lot of rust you should probably strip the primer and scrub the whole surface to get rid of the rust. I use self-etching primer on bare steel blocks. Works very well. Scrub the block again with ScotchBrite and laquer thinner to prep for primer. Paint with whatever color you want.
Mark
 
#9 · (Edited)
Never let a part set in phosphoric acid solution more than an hour before washing it with fresh water. If the part has any threaded holes, the acid solution will weaken the threads

Before the government closed most of the hot tanks for car parts, you could take the parts to one of those locations to get them hot tanked in a alkaline solution. However an alkaline bath is just as hard on threads as phosphoric acid (Metal Prep)but parts can remain in a hot alkaline bath longer and get cleaner than in a Metal Prep solution.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top