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Technical What to apply after sandblasting frame?

Discussion in 'The Hokey Ass Message Board' started by Shakedown St., Sep 22, 2017.

  1. Shakedown St.
    Joined: Sep 15, 2017
    Posts: 124

    Shakedown St.
    Member
    from Boston, MA

    After sandblasting a frame, is there anything you should coat the exposed metal with?
     
  2. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,338

    DDDenny
    Member
    from oregon

  3. King ford
    Joined: Mar 18, 2013
    Posts: 1,242

    King ford
    ALLIANCE MEMBER
    from 08302

    I have done several with POR15 ,,,,,great results
     
  4. Dick Stevens
    Joined: Aug 7, 2012
    Posts: 2,609

    Dick Stevens
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  5. Budget36
    Joined: Nov 29, 2014
    Posts: 2,376

    Budget36
    Member

    Lotta air to get rid of the excess sand....then you need to wipe it down with your favorite brew to get oils/contaminates and such out/off of it...now you have clean, ready to work with bare metal...treat as you would a door, fenders, car, etc....really depends on how soon you are going to act on it...if this is a weekend project just grab your primer and paint and go, will probably outlast both of us...if the frame is gonna sit for a week/month etc...then that changes the way to approach it.

    I'm one of those impatient bastards when it comes to a frame...shoot my cheap primer, semi gloss black..and be done with it, then again I don't build show cars...do you?
     
  6. ceege
    Joined: Jul 4, 2017
    Posts: 204

    ceege
    Member
    from NW MT

    And within 8 hours of the blasting operation.
     
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  7. X3
     
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  8. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,280

    29moonshine
    Member

  9. NashRodMan
    Joined: Jul 8, 2004
    Posts: 1,576

    NashRodMan
    Member

    Can you buy epoxy primer in a spray can or does it only come for use in spray guns?
     
  10. Sporty45
    Joined: Jun 1, 2015
    Posts: 689

    Sporty45
    Member
    from NH Boonies

    Yup, but I have never used it. Not sure how good it is.
    [​IMG]
     
  11. hotrod428
    Joined: Feb 7, 2007
    Posts: 268

    hotrod428
    Member

    I am not a fan of por15, its a lazy mans way to paint a rusty frame. Have you ever tried working on a frame that's been painted with it? You can't get that shit off to weld. If it's already sandblasted, epoxy primer and a coat of good enamel with hardener.
     
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  12. Deuce Daddy Don
    Joined: Apr 27, 2008
    Posts: 4,851

    Deuce Daddy Don
    ALLIANCE MEMBER

    Use long lasting POWDER COATING!!!!!
     
    Dave Mc likes this.
  13. After sandblasting I wipe the entire frame down with a final prep cleaner,to remove the excess residue.

    [​IMG]

    In my way of thinking the primer depends on the car I am building,in this case it's the frame under the '54 Ranch Wagon and basically none of it would show unless it's on a rack and the car was built to drive,not show so I actually brushed on a slightly thinner coat of Rustoleum red oxide primer.

    [​IMG]

    After it had dried I painted it with semi-gloss industrial enamel black,I brushed it also.

    [​IMG]

    [​IMG]

    It has held up well. HRP
     
  14. TagMan
    Joined: Dec 12, 2002
    Posts: 5,890

    TagMan
    ALLIANCE MEMBER

    I first used etching primer and within 3-months I could see rust coming through. I had to re-blast and paint it with Epoxy primer stored the frame for 2-years with no sign of rust. Use Epoxy primer !!
     
  15. 2935ford
    Joined: Jan 6, 2006
    Posts: 3,160

    2935ford
    Member

  16. King ford
    Joined: Mar 18, 2013
    Posts: 1,242

    King ford
    ALLIANCE MEMBER
    from 08302

    i agree on the painting over rust being for " lazy men" I do not advocate that,HOWEVER moisture cure urethane is the toughest most durable finish I have ever seen, I have used it straight over sandblasted frames, axles,transmissions etc.and it appears indestructible!...as far as welding I sand it off with a " flapper disc" to bare metal, put a clean new disc on and hit it one more " quickie and weld.....but I am just building " nice" driver quality not show car stuff
     
  17. GASSERBOB
    Joined: Nov 26, 2010
    Posts: 520

    GASSERBOB
    Member
    from USA

    Eastwood sells epoxy primer in spray cans also.
     
  18. Adriatic Machine
    Joined: Jan 26, 2008
    Posts: 160

    Adriatic Machine
    Member

    I was taught epoxy primer has to be a two part mixture and must sit for 1/2 hour after mixing to get the desired chemical reaction. Then stir again before application. I would not believe a one-part product is epoxy just because the label says so. I had used mil spec epoxy primer for many years while in the military, highly recommended, excellent results. After application you must topcoat within a certain amount of time or you will have to scuff sand before doing so. Whatever you use, do NOT let that freshly blasted metal sit uncoated for any longer than it has to. It will flash rust before you can get back from the paint store.
     
  19. Adriatic Machine
    Joined: Jan 26, 2008
    Posts: 160

    Adriatic Machine
    Member

    As far as etching primer, I used it once a while ago. It did ok but the car has not left the garage since. In my opinion, an etch is a separate operation and not even needed on metal that has just been sandblasted / roughened.
     
  20. alchemy
    Joined: Sep 27, 2002
    Posts: 14,376

    alchemy
    ALLIANCE MEMBER

    You guys who say you need to paint within hours must live underwater. I live in humid Iowa, and have parts that were blasted years (maybe even ten) ago that are still bare clean. Maybe a fingerprint of rust where I picked it up with sweaty hands once.
     
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  21. Paint_Rep
    Joined: Feb 10, 2017
    Posts: 62

    Paint_Rep

    You need to shoot a good two component epoxy like PPG's DPLF or DPLV. That's the only right way to seal the bare steel. Etching primers are 1K acid-activated and can be reflowed with aggressive chemicals. Etch's can't be topcoated directly, and don't like a rough profile like sandblasted steel. DP Epoxy and a coat of a single stage black urethane or enamel over it and that frame will last 100 years...


    Sent from my iPhone using H.A.M.B.
     
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  22. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,338

    DDDenny
    Member
    from oregon

    Yes, I think etching primers are more suited for chemical dipped steel and soda blasting.
    A friend told me he had a car soda blasted years ago and said he had a hard time with paint adhesion.
     
  23. safari-wagon
    Joined: Jan 12, 2008
    Posts: 1,457

    safari-wagon
    Member

    I apply a good amount of Metal Prep to any bare metal. It's a phosphate based solution, which is what the OEMs use for rust prevention.
    Lately, I've been using a high zinc spray primer over that "prepped" metal. It mimics the properties of galvanized metal.
    Then you can lay down your chassis black.
    The OEMs figured this out decades ago.

    Singlefinger Speed Shop,
    still lurking around Detroit
     
  24. I'm certainly no expert on paint or primers. I trucked my bare frame home from the sandblasters and shot it with etching primer 9 years ago. It's in a damp garage and hasn't rusted yet. The etching primer grinds off easily to weld but when it gots hot, it sends off nasty fumes! I'll do my finish welding and shoot it with a good primer and then paint.
     

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