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Technical light rust - is rust converter TRULY legit prior to paint ??

Discussion in 'The Hokey Ass Message Board' started by robert ehlers, Dec 1, 2021.

  1. robert ehlers
    Joined: Dec 1, 2021
    Posts: 2

    robert ehlers

    I have light rust on the cab of my 50 studebaker pickup - for sure sanding to bare metal and priming and painting solves it ... BUT is using a rust converter or encapsulator after light sanding really possible nowadays?

    Plan to top coat with a single stage white, and I am fine with imperfect vintage vibe on the new paint.

    Attached Files:

  2. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 5,285


    That's not "light rust", that's significant surface rust. Even if it were light rust, it would still need to be stripped completely bare prior to any form of paint or filler for any kind of lasting work. The rust pushes with an unbelievable amount of force and will eat the paint and filler right off the car.

    Using a rust converter or encapsulator is a cop out IMHO, and a big gamble. The only correct answer is to remove the rust entirely. Most of that can be remove with a polycarbonate disc on a right angle grinder to take it all to bare steel, and if anything is pockmarked, some light spot blasting or wire wheeling should get the rest of it.

    "Imperfect vintage vibe" sounds a lot like a premature acceptance of poor workmanship. I don't like that at all. Doing your best and not making excuses is traditional.
    wvenfield, rockable, X38 and 3 others like this.
  3. oldiron 440
    Joined: Dec 12, 2018
    Posts: 2,827

    oldiron 440

    Those products are an excuse for not doing a proper repair....
    samurai mike and squirrel like this.
  4. robert ehlers
    Joined: Dec 1, 2021
    Posts: 2

    robert ehlers

    Roger that. Thanks.
    Flathead Dave likes this.

  5. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 3,637

    Flathead Dave
    from So. Cal.

    "Roger, Roger...Who's Roger?"
    lippy and Lloyd's paint & glass like this.
  6. When I was younger, I had an incident with a trailer that was chasing my car. It caught up to me and damaged the quarter panel (an off topic car). During the repair, I ended up driving around for quite a while in bare metal (not the entire car) and rust quickly formed. I am sure the rust I had was nowhere near the age yours is but I do remember using a product called Metal Prep. It was a liquid, you used gloves, goggles and steel wool and scrubbed it in then wiped it off before it dried (going by memory here). It worked unbelievably well. The metal came out looking new. Now, that was a LONG time ago and what they sell as Metal Prep now may not be anywhere near the product they sold years ago. Your result, if you choose to attempt, may vary significantly. Keep in mind, my rusty metal had not rusted long enough to pit.
    Last edited: Dec 1, 2021
  7. gimpyshotrods
    Joined: May 20, 2009
    Posts: 19,927


    Jasco Prep-n-Prime, or OSPHO will get you closer to clean, but still, after you use either product, take the rest down to bare metal.

    Using these products first will take the rust off, without you having to resort to taking metal and rust off, just to get the rust off.

    Either/both are sold at hardware stores and home centers.
  8. Tman
    Joined: Mar 2, 2001
    Posts: 36,064


    I second the Jasco. Using it on my GMC
  9. guthriesmith
    Joined: Aug 17, 2006
    Posts: 6,469

    1. H.A.M.B. Chapel

    And, I second the Ospho. I used it in my 66 C10 and was amazed with the results. Still need to go to bare metal, but it sure took the rust off for me.
    winduptoy likes this.
  10. Rust converter is for chassis and the like. On body panels scuffing is always your best bet. (well with some exceptions of course)
  11. kasselyn29
    Joined: Dec 18, 2009
    Posts: 223


    You guys should check out Proshaper on u-tube Wray shows alot of diferent ways to clean and prep metal Excelent information using bacis tools and affordable products.
  12. 6sally6
    Joined: Feb 16, 2014
    Posts: 1,894


    " I knew-a-guy"........(you know how that goes) that used POR-15 and primered & painted over it and it was a black (M-word).
    It had rust on the quarters and several other common places. NOT cancer or rot but rust none-the-less. 6/7 years later it still looked sharp.
    It got folded up by a tractor-trailer or the guy would still be driving it.
    POR-15 does NOT work unless it is applied over rust. Wire brush the loose stuff and follow the instructions.
    DO NOT!!!!.....get it on your hands. Jus say'in
    Flathead Dave and kjmmm like this.
  13. gene-koning
    Joined: Oct 28, 2016
    Posts: 2,835


    So, 23 years ago, I moved a business to a different location. I threw together a metal sign spray bomb painted base with vinyl lettering, and put it in the grass at the new location. It was suppose to be a temporary sign.
    About 4 years later, the spray bomb paint was failing and rust was developing fast, the vinyl lettering was holding up a bit better.
    I pulled the sign down on a slow couple of days, sanded it smooth, and covered both sides with POR15, than after it was dry, I painted the sign with brushed on enamel paint, and another round of vinyl lettering.
    Ten years later, I had to replace the vinyl lettering, so I changed the color of the paint on the sign, but what was there still looked great. I just changed the color on the front side of the sign, and added another round of vinyl lettering (different color this time).
    When I retired in 2019, I pulled the sign out of the yard. The front looked good, but the back side was showing a few bubbles under that original POR 15. The sign hangs in my son's garage.

    I'm not a big fan of POR 15, I've had several failures of it, and quit using it shortly after the sign was painted, but I do use a rust encapsulate on anything that had even surface rust before I move forward on any body or paint work. Gene
  14. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 8,726

    Bandit Billy

    On my 41 PU which I am painting currently, it had a brown rust layer under the primer that was on it when I bought it (and a hole or three under some old bondo). After scotch brite and 80 grit DA I could not get rid of a brown hue in the metal, that you can see below.
    I called my paint store and they checked with their reps and it was recommended that I apply Rust Mort to the bare steel and scotch brite it the next day. The results were a clean metal finish with black where the brown used to be. After welding up the holes (I think that was a spot light) I put it in epoxy primer before it could flash rust.

    Rust mort has it's place but the OP needs to strip that cab first and use the rust convertor only if sanding can't completely eliminate the oxidation.

    Oh and if care about your garage floors finish, put down a drop cloth prior to applying the convertor. Those white spots in the lower right side of the pic above appear to be permanent. At least my floor won't rust. :cool:
  15. pirate
    Joined: Jun 29, 2006
    Posts: 712

    from Alabama

    Ospho and other phosphoric acid based products will remove/convert rust (iron oxide) to iron phosphate. If rust was heavy I agree that the coating should be removed down to bare metal. However, the iron phosphate coating remaining after treating with phosphoric acid actually etches the metal and provides a good surface for primer or paint to stick to. Some Mil- Specs actually require this treatment before painting on military contracts.
    gimpyshotrods likes this.

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