rust question for beginner


New member
I'm new to painting and restoring a car. It still had the factory paint but I have decided to strip the car back to bare metal with sanding discs. I have found no rust or surface rust in any of the panels once I removed the paint. I was told by someone once stripped to wash the panel with a scotch brite pad and a mix of vinegar and water which I did. Then repeat the process with just water, then dry the panel off, wax and grease the panel a couple times to ensure completely clean surface then epoxy prime. I have only worked on 2 panels at a time so the day I stripped them they were epoxy primed. My question is can rust develop under my epoxy primer down the track for whatever reason or is it highly unlikely with the process I have taken in restoring the panels? How does the rust develope under a primer?


Staff member

As long as you did a good and thorough job on everything you did, you should be fine.
As soon as metal is exposed to the elements, the rust process begins.


You asked how does metal rust under the primer? Well, primer is porous, different types have different degrees of porosity. Epoxy is one of the best for being water resistant, so for a short time, your primered surface should not be prone to letting moisture in, to rust the metal underneath.
Other primers have less water resistance. Primer is, by nature, porous, so that the succeeding paint layers can absorb into them, for good adhesion. They are not meant to be a final finish. If you want a flat finish, you would be much better off using a semi gloss, or flattened paint, rather than primer.
Or try to put you car in paint as soon as you can. If indoors, not much of a problem, if it is outdoors, even spoxy should be covered in paint after 3-6 months, as it will eventually brake down due to water, and UV exposure.


New member
Thanks for the help. As far as the car and panels they are stored in my garage so they are out of the weather and it should be completed in paint within three months. Taz you said that as long as it hasn't been exposed to the elements I should have no rust issues. By washing the bare metal panels with vinegar water hasn't this exposed it to the elements? I was very detailed with the process I followed and the panels were pretty much glowing they were that clean when I put my epoxy on and i could see no surface rust on the panels. Can rust already be forming and not be seen to the naked eye? I guess I could understand if they were sitting around for a few days in bare metal but as I said earlier the day I strip the panel is the day I prime it. Is the vinegar water a necessary step to take or can a panel be stripped, wax and greased then primed? I was nearly considering putting one coat of a rust inhibitor before I epoxy primed but was not sure if it was a good idea.