Should I sand blast, and if so, what size sand? I have a door and fender I need to prep for POR 15 and paint before I install, but want to do it "right" before I start to install it. I have sandblasted cars in the past, but used too coarse a sand and pitted the metal. Is there a better way to get down to the metal to prep for POR 15 and paint?
I have found hydrocloric acid to be the best method of removing rust, it attacks the rust but only mildly etches metal that is not rusted. The blend I use contains 33% acid. If you try this protect your self (skin, eyes and don't breathe the fumes) and do this in a well ventilated place (outside).
POR-15, Rust Encapsulator, and Rust Bullet are really made to use right over the rust. Remove the loose rust with a steel brush, cup bursh, etc., clean the surface to degrease, etc., and put on the POR-15. I'm presently using Rust Bullet on my '77. It becomes a self-etching primer. You can sand and paint it. However, I would not use it on the outer skins of the car.
I don't think you can paint over por 15, we tried 2 coats of it on dump truck wheels, and the 2nd coat peeled right off the first coat, the first coat has held for a few years now.
Suppose I don't use POR 15...what is the "correct" way to get a painted (not necessarily rusted) metal body panel ready for paint. The door and fender have no rust, just a few small dings, but before I put them on the car, I want to have it down to metal and POR 15 the insides, and prime and paint the outside. I just don't know the correct way to remove the existing paint and prep the metal for new coatings. I will probably paint the entire car one panel at a time, down to metal, prepped, straightened, and prime and paint. then when the whole car is one color (probably an epoxy primer) and straight, I will have it professionally painted (much later down the road) my color of choice. I will POR 15 all hidden parts, inside the metal, and probably the frame rails.
If the original factory paint is still decent ... don't remove it ... just sand it down until the factory primer beings to show, seal, prime and paint it ...
On the fender and door, I am not sure if it is factory paint. I am pretty sure it is not, or at least has had a second coat painted over it. I still want to POR 15 the inner surfaces. Should i use sand blast or chemicals, or what to strip it to metal?
I've heard sand-blasting can heat and warp body panels (especially thin-metaled panels, like Mavericks) and excess sand can be hard to remove from crevices, can atrract and hold water, thus leading to future rust. Using a plastic bead, or walnut shell media for blasting might give better results. Chemical stripping works well, but it's messy and toxic. Sometimes good ol' sanding works best. As I said, this is what I've heard and read......will find out myself soon enough....when I start on sanding and prepping my 64 Galaxie and the 69.5 Maverick for paint. I'm planning on DA and hand-sanding both cars, since both have original paint, and the old paint is already worn and thin.
I will have to look into walnut and plastic... Sounds kinda expensive... I use walnut and corn husks for cleaning brass bullet casings, and I know how much I spend on those...
Doesn't POR-15 make a paint that's meant to go over their sealer stuff? I was browsing their catalog a few weeks ago and I swear I saw something. Also, my Maverick is missing the headliner and the metal is pretty rusted. Would prepping it and then coating it in POR-15 be a good idea to help protect it until I can locate or make a headliner? Reading these posts got me to thinking...I was going to just use primer but I think the POR is much tougher.
What is "sealer"? I look at the store and see lots of primer and paint, plus I have my POR 15, but nothing says "sealer"
