Rust converter thoughts

[Kevin 007]

Its time to paint my 84, not cause I want to but because the surface rust is taking over. Ok, so after the final sanding; id like to apply a rust converter to all the rusty areas, like a Plastikote or Rust Mort. I have the Plastikote so i'll probably use that. I don't have much experience with a rust converter, does anyone have any tips or thoughts?

 

[franklin2]

This is on the outside body? What are your long term plans for it? If you plan on ever taking it somewhere to get a official paint job on it, I would be hesitant to put something like those products on it. Automotive paint has strong chemicals and can attack some of the do it yourself products you buy at the store. Then you get alligator checks in the paint and the top coat flaking off.

 

[tbrumm]

If you are prepping to paint the exterior of the truck, and plan on a decent paint job being the final result, you pretty much have get down to good, clean metal in the rusted areas. Sand blasting, soda blasting, grinding, etc. Then seal with an epoxy primer. If you are trying to keep the rust in check for a while until you get to the real paint job, I might suggest using a "rust encapsualting" paint rather than a rust converter. The rust converters usually have latex in them to provide seal after they have "converted" the rust and that doesn't work very well in my experience. Yeah, they "say" you can paint over it but I have not had good luck. My suggestion would be to scrape/grind/wirebrush the loose rust off the areas. Then hit the areas with a product called "OSPHO" which is essentially phosphoric acid. I think this is one of the components in the rust converters that does the so called "converting". You can get the stuff at most hardware stores and big retailers like Home Depot. and is usually less the $30 a gallon around here. This will "eat in" to the outer layer of rust and neutralize it a bit so it acts a better base for the paint. Following letting this try thoroughly, paint over the treated areas with a rust encapsulating paint such as Eastwood's Rust Ecapsulator, Chassis Saver, Rust Bullet, etc. If these painted areas are on the outside of the truck where they will get exposure to sun, you will need to paint over the rust encapsulating paint as the UV rays tends to make them get "chalky" looking. As I understand it, these rust encapsulating paints cure from atmospheric moisture and also the moisture in the rust and that is why they stick to the rust like glue (and to everything else so protect your skin). By sealing so well, these paints deny air and moisture to the rust so it can't continue to grow, but the rust is still there. If any air/moisture gets through, the rust starts growing again. That is why it is so important to get all of the rust off before a nice paint job as the rust encapsulating paint is not absolute. Get a crack or chip in it that breaks the "seal" and the rust starts again. I use the stuff on the frame and underbody of my truck, and "re-do" the problem areas before winter each year. I am getting ready to do it again now. It is a lot of work, but helps the underbody survive the 5 months of liquid salt bath the truck must endure every year.

 

[laserjock]

Here is my philosophy. Take it for what it's worth. I do the best I can to get the metal clean but sometimes it's not feasible. See my build thread and the underside of the cab floor. For areas that are getting chassis black, I have been using POR metal ready. If it's real bad, I start with ospho. Both have phosphoric acid in them which will convert iron oxide to iron phosphide. That only works in so deep so you really have to be down to close to clean or you are wasting your time with them. If you read the directions, you are really supposed to keep it wet and not let it dry before it is rinsed off. What I like to do is wet it down with chemical and start working it in with a scotchbrite pad. That will help get it in there and get rid of any loose stuff the acid may release. If I'm doing the underside of things, I rinse and shoot por15 over it. I don't know if it's the greatest thing ever or not but it claims to be compatible. On my frame, I did the same treatment after it was sandblasted and started to flash rust on me. I put tractor supply implement primer and paint over it and so far it has held up good. It sat outside all last winter and still looks good.

On the body panels where I have flash rust to deal with, my plan is to grind it back as best I can and hit it with metal ready to get into any pits that may be there, then sand it again to clean any residue off the surface o don't want and prep for paint.

Whatever you do, make sure to read your tech sheets for your products to be sure they are compatible with what you want to do.