So painted my jcr bumper. Primed and rustolem satin over all good, but after a few days of exposure a little rust is peaking through on one corner. Should I just rattle can or sand, primer, paint? I don't think initial primer took well... I am a litte OCD about these things but I did spend alot on this mod!

 

Pic is not as bad as it looks in person, trying to be proactive.

 

I would just rattle can that way you don't danger making it hard to match it back up. And if that doesn't work, go ahead and sand and redo..

 

If you have rust, you can't just spray over it. The rust will eat through the new paint and be back again. You must sand off the rust completely to bare metal. Then apply primer/paint. Rust is like cancer, you can't cover it up, you need to cut it out so that it does not spread anymore.

 

POR15 is a rust inhibitor, you can paint right over it. You are better sanding the rust off and then sealing it though.

 

I used to think that way too, but with some of the products on the market today you can paint over the top of rust and be successful at stopping its progression. Having said that, I would probably sand it down to bare metal and hit it good with some self-etching primer, then some surfacer and paint(or bedline).

 

Ideally it is best to use a metal prep then follow up with a self-etch or epoxy primer then top coat. Check specs on can of paint sometimes you might have to wait for it to cure a certain amount of time or the product might lift. Then you will have to take the whole thing down and start all over...good luck..

As for Por15....excellent product i used on some rusty metal then top coated with an industrial polyurethane that was a three part mix ratio.