primer on bare metal questions

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  • biotex
    258 I6
    • Apr 30, 2009
    • 292
    #1

    primer on bare metal questions

    I have spoken with Dupont Technical Support, three body shops, and a few other people knowledgeable in painting, and I get conflicting information. I want to know what is the preferred way to prepare bare sandblasted metal for body work.
    The Dupont guy said to apply the epoxy primer first, DA it with 180 grit to bare metal over the repair area, then bondo, then sanding primer. This method sounds like the correct way to me, but the bodyshops say not to put bondo over bare metal. Supposedly moisture can get between the bondo and metal. When I asked the tech guy about this, he said there was no way for that to happen as long as there are no holes in the metal.

    Anybody know the correct procedure for applying Epoxy Primer, Bondo, Sanding Primer over bare metal?
    1986 CJ7, AMC 304/ T-176
    1968 Scout 800, 152/T-18
    1971 Scout 800B, 345/727
    CJ10-A Tug,Waggy axles, Sd33, 727
    Tags: None
  • rixcj
    258 I6
    • Aug 02, 2007
    • 333
    #2
    One of my customers builds custom steamboats. He has done extensive research ( pretty much his own trial and error ), on the properties of different types of body fillers.

    The typical Bondo that most everyone uses WILL absorb moisture, and could eventually bubble ( something about the talc content).

    Apparently, some fillers are better than others. I don't know exactly which fillers are best, or what to recommend, but I just wanted to get this out there.

    The next time I see him, I'll ask more about this (if I remember.... ).

    Rich
    1979 CJ5 with a 401...it goes a short way on a lot of fuel...https://forums.ifsja.org/core/images...tom/drivin.gif

    401, T176/ dana 300, amc20 (Mosers), D.U.I. HEI, Edelbrock Performer intake, Holley 670, ps/pb, 'glass tub, 1 pc tilt nose.

    There's a fine line between "hobby" and "mental illness".

    Comment

    • tgreese
      approaching Ristows' level of B.S
      • May 29, 2003
      • 11682
      #3
      If you follow the body shop's advice, you need to use an epoxy primer that allows filler to be applied over it. It's important which primer the body shops guys (that say to paint under the primer) are using. Everybody seems to like the PPG Deltron DPLF epoxy primer. The tech sheet for this primer specifically says that you can apply body filler over the primer. Note that epoxy primer will cure too hard for recoating after a week, so if you coat the metal with DPLF and then fill, you'll need to finish your body work and spray either primer-surfacer or color within the same week. Or else sand all the surfaces before you recoat.
      Input string was not in a correct format.
      https://buyat.ppg.com/refinishProductCatalog/ViewProduct.aspx?ProductID=ebd75e7f-7489-4334-a387-73f8653e2a34


      My reading says that putting filler directly onto roughened metal is the common old-school way to do it. You then wipe down with degreaser and coat with epoxy primer. Your top coat will seal out any moisture, as long as there are no holes in the metal.
      Last edited by tgreese; 05-06-2009, 03:58 PM.
      Tim Reese
      Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
      Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
      Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
      GTI without the badges: '95 VW Golf Sport 2000cc 2D
      ECO Green: '15 FCA Jeep Cherokee KL Trailhawk

      Comment

      • OBX-AUTOMOTIVE
        GRUMPY
        • Apr 10, 2001
        • 6875
        #4
        SAY YOUR FIXING A DENT,YOU DING IT OUT, THEN YOU GRIND IT WITH 24gt,THEN SKIM COAT BONDO,THEN SAND, THEN GLAZE, THEN SAND, THEN PRIMER ,THEN SEALER!!

        THIS IS WHAT I USED DOING BONDO....1/2 ROUND CHEESE GRADER, 36gt/80gt

        IFYOU WANT TO SHOOT CATALYST, WITH OUT A PAINT BOOTH,THEN,YOUR CRAZY!

        The Dupont guy said to apply the epoxy primer first, DA it with 180 grit to bare metal over the repair area, then bondo...THAT GUY IS SMOKING SOMETHING!....

        I BET YOUR ASKING YOURSELF,HOW DO I KNOW ALLLLLL THIS STUFF???

        WELL.BECAUSE I'VE DONE BODY WORK ON THOUSANDS AND THOUSANDS, OF CARS/TRUCKS!

        AND DON'T HAND ME ANY OF THAT "OLD SCHOOL" SHEET!!.... BASIC BODY REPAIR HAS NEVER CHANGED,ONLY THE PRODUCTS!
        Last edited by OBX-AUTOMOTIVE; 05-07-2009, 03:49 AM.

        Comment

        • OBX-AUTOMOTIVE
          GRUMPY
          • Apr 10, 2001
          • 6875
          #5
          OH! ONE/OTHER/THING!
          AS FOR >>>> DEGREASER,YOU ONLY USE DEGREASER WHEN YOU FIRST WIPE DOWN THE PAINT,AT THE START!

          YOU NEVER USE DEGREASER ON PRIMER,SEALER OR BARE METAL!....DO YOU KNOW WHAT "FISH EYES ARE"?

          BUT!! HEY!! YOU DO WHAT YOU WANT!
          Last edited by OBX-AUTOMOTIVE; 05-07-2009, 04:15 AM.

          Comment

          • obx2ack
            230 Tornado
            • Jan 09, 2009
            • 21
            #6
            I'm restoring my 88 GW and ran into some of the same questions. Check out hotrodders.com forum. Here is a link.

            http://www.hotrodders.com/forum/search.php?searchid=2596699


            You will find that there are many different opinions on the process. Here is what I decided for bare metal (no rust, clean shiny bare metal). I used all Dupont products

            1. Prep sol bare metal with white lint-free cloth until clean
            2. DA 80 grit
            3. Prep sol again
            4. DA 120 grit
            5. prep sol
            6. final clean
            7. epoxy primer
            8. 180 grit
            9. body filler
            10. epoxy primer
            11. 320 grit scuff
            12. primer filler
            13. block with 500
            14. repeat primer filler and blocking until happy
            15. primer sealer
            16. base
            17. clear
            18. wet sand
            19. buff
            20. wax

            It may be overkill. Probably is, being that I'm only on step 7 and havent driven it in two years.

            Check out that forum. Great guys and a world of knowledge. Hope it helps and good luck.
            87 GW
            88 GW
            71 Bronco
            76 J54
            05 LR3

            Comment

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