Stripping paint and prepping car for paint

I used the gel-type. Works, but sometimes takes several coats, and you have to sand after.Pain in the butt. Since I was doing a "farm truck"/parts hauler, I eventually decided that the paint wasn't that bad and only stripped the front (cab), just sanded the rest. Can't tell now. held up good so far, about 4 years parked outside, washed maybe once a year. If you sand through the old paint, or use the stripper paint it as quickly as possible -not just primer, but some type of sealer. Primers and flats will still let moisture through, that means RUST. In hot humid conditions, you can get a coating of flash rust in hours.