So I have a bit of rust on the passenger side A pillar at the top of the windshield. There is some heavy pitting but nothing that has gone thru. I was hoping to use evap-o-rust or other chemical product to do this. However, most need to be constantly drenched with the chemical to work. So I thought I could make a temporary wall around the rusted area that would hold the fluid to dissolve the rust then remove and prime/paint. However, options for sealing the temporary wall to the car seem limited to cord caulk or maybe butyl tape. I know that RTV is safe for the paint but would be very difficult to remove and being that it has silicone would make it harder for the paint to stick.
Has anyone else tried this method of rust removal? If so, how did you do it?