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Best primer for old steel

Discussion in 'The Hokey Ass Message Board' started by Abone29, Jun 15, 2010.

  1. Abone29
    Joined: Mar 20, 2007
    Posts: 234

    Abone29
    Member

    What do you guys use for primer on old steel? I've about finished grinding the 80 year old rust off my Model A and need to get it in primer.Should I use an etching primer? If so what brands do you recomend?
     
  2. 40StudeDude
    Joined: Sep 19, 2002
    Posts: 9,454

    40StudeDude
    Member

    I use an epoxy primer/sealer on all my cars...DPLF50...PPG brand, been using it for over 10 years. I'm sure there are other brands just as good...and I'm sure you're going to hear about them shortly...

    DPLF50 is water resistant, but do not run the car this way for very long, or outside in the weather...just about any primer is porous, meaning water will creep under it and rust the surface again. Is there any humidity in MS...???:rolleyes::rolleyes::rolleyes:

    R-
     
  3. Weasel
    Joined: Dec 30, 2007
    Posts: 6,693

    Weasel
    Member

    I treated my cleaned and stripped metal with Rust Destroyer red oxide primer which I got from Home Depot. It takes a while to dry but has protected the metal perfectly. I will use an automotive primer on top before I paint.
     
  4. Ice man
    Joined: Mar 12, 2008
    Posts: 984

    Ice man
    Member

    What is the route to take for paint wrinkling up around the filler on my 29 Pk Up. Its got single stage on it now, but just at the filler its all wrinkled, I even sealed the threads with teflon. Not sure what to do next. Iceman
     

  5. skullhat
    Joined: May 30, 2009
    Posts: 892

    skullhat
    Member

    etching primer , then a filler prime is the best way if you are painting it soon, and the body work is done.

    if you just stripped it, and still need to do body work, and its gonna be in primer while, the the dp stuff from ppg is the way id go as stude advises.

    the absolute best, is to walnut blast, metal work, etch, fill, block, re-fill and repeat till straight, seal, paint......theres my 30 second advice, to a year long job, lol



    skull
     
  6. RDR
    Joined: May 30, 2009
    Posts: 1,355

    RDR
    Member

    Used RODDA Barrier III an enamel bare metal primer sealer.... was $24.00 a gallon 11 years ago when I painted the Chevy....The State of Oregon workers call it "Bridge Paint" cause that's what they paint bridges with all over the state....painted base coat/ clear coat Sherwin Williams over top (Acme at the time)...has held up real good....It comes in a high solids, too..can't beat the price
     
  7. Abone29
    Joined: Mar 20, 2007
    Posts: 234

    Abone29
    Member

    Thanks for the info guys.I am not finished with the body work yet,but have all the patchwork done.Still have a little grinding on welds to do.Yeah Stude,it's kinda humid down here right now.Makes it miserable doing anything outside.Thanks again guys.
    Glenn
     
  8. skullhat
    Joined: May 30, 2009
    Posts: 892

    skullhat
    Member


    if its like the filler on some motorcycle tanks, you need to seal the edge where paint starts and bare metal ends.

    while the paint is gas proof, the edge is not, as its porous (sp) and the fuel wicks under the primer and lifts the paint.

    all you need to do is wipe a little crazy glue or epoxy around that edge ,and the gas will no longer be able to wick under the paint.

    unfortunatly , at this point you will have to strip the area affected and repaint.

    also good idea not to fill the tank to the very top oif the filler spout.

    good luck


    skull
     
  9. The_Forgotten
    Joined: May 6, 2009
    Posts: 83

    The_Forgotten
    Member
    from WNY

    No wonder the cheap bondo jobs I've seen to fill in rust spots around a filler neck never last! Doubt that the car flippers take the time to seal the filler edge. Thanks for the (future) tip!
     
  10. ZRX61
    Joined: Jul 10, 2006
    Posts: 175

    ZRX61
    Member
    from The AV

    Etch primer affects the filler from kicking off completely leading to premature failure of the filler to stick to the sheet metal.
    Filler really only bonds to two things:
    Clean sheet metal or epoxy

    I usually hit the sheet metal with the 5in grinder with a 36 or 50grit disc & run it slow to really gouge up the metal to give it some teeth... then filler, or epoxy then filler.
     
    Last edited: Jun 16, 2010
  11. 46binder
    Joined: Jan 21, 2008
    Posts: 245

    46binder
    Member
    from Kenosha,Wi

    I am using SPI epoxy, on bare metal, filler over it and epoxy to seal it. Much better protection against moisture. Acids in self etching can react with epoxy and cause adhesion problems.
     
  12. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,953

    SlowandLow63
    Member
    from Central NJ

    The two basic routes are etch and a high build urethane, or epoxy. Each will come with its own band of chest beaters.

    I vote the epoxy route. Kills two birds with one stone.
     
  13. flamedabone
    Joined: Aug 3, 2001
    Posts: 4,923

    flamedabone
    Member

    .....and...just to add to the confusion...there are those that say if you put Bondo over self-etching primer, the Bondo will "pop off" not long after application due to how the self etch cures.

    It has always sounded like a wifes tale to me, but both my local paint stores say don't do it.

    I used DP90 on my bare metal...good luck, -Abone.
     
  14. john worden
    Joined: Nov 14, 2007
    Posts: 1,700

    john worden
    Member
    from iowa

    Weasel, a word of caution. If the primer was slow to dry it may be an alkyd type primer and not compatible with modern catalyzed automotive paint products. You may have to stay with alkyd based products or strip it and start over. In the day alkyd primer surfacer ( Dupont Preparakote was one ) was a better but slower and more expensive alternative to lacquer primer surfacer. Custom and resto shops that wanted their paint work to really last used it. It would stand up to lacquer solvents if used carefully.
     
  15. john worden
    Joined: Nov 14, 2007
    Posts: 1,700

    john worden
    Member
    from iowa

    I think your stores advice is good. I've never read or seen paint or filler makers recommending filler over any primer but epoxy.
     
  16. SaltCityCustoms
    Joined: Jun 27, 2007
    Posts: 1,210

    SaltCityCustoms
    Member

    I always go epoxy, its compatible with your filler, helps corrosion protection and if reduced can usally be sprayed as a sealer.
     
  17. VOODOO ROD & CUSTOM
    Joined: Dec 27, 2009
    Posts: 1,238

    VOODOO ROD & CUSTOM
    Member

    EPOXY, EPOXY, EPOXY, EPOXY, EPOXY. You can Epoxy the whole (Bare Metal) and spread your Bone over the Epoxy. Wait about 4
    Hours before spreading the Bone. You can then leave the body like this and finish the Bone the next day, or Two, or Three.......
    Once you've finished up all the Bone work, Epoxy the whole vehicle, wait 4 hours and put on a Fill Primer. Then Block like
    Hell ! ! !

    Good Luck.
    VOODOO
     
  18. john worden
    Joined: Nov 14, 2007
    Posts: 1,700

    john worden
    Member
    from iowa

    I believe that grinding and sanding leaves microscopic bits of rust waiting to bloom again in your humid climate. Etch primer will certainly stick to your scratches but won't kill or convert the rust. I suggest using a rust converter like SEM Rust Mort or an acid wash after sanding or grinding to completely rid the surface of rust. Following with etch primer would be good but somewhat redundant. Consider any major brand of epoxy instead and use the slowest activator to allow the primer to creap into your scratches before it dries. Take your time and maybe do a panel at a time. This will result in an excellant foundation for future work. luck
     
  19. Polyesters can be put over etch primers but you need to be absolutely sure that the etch has fully dried. If it is not fully dried the etch continues to release acid(the part that causes it to etch) and that will react with the filler resulting in bad things happening.
     
  20. superchiicken
    Joined: Aug 3, 2009
    Posts: 123

    superchiicken
    Member

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