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How long before flash rust shows up after sandblasting???

Discussion in 'The Hokey Ass Message Board' started by tlmartin84, Aug 21, 2012.

  1. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    Getting my frame blasted, how long can it set in my garage before flash rust starts appearing??

    Ideally it would get painted the next day but thats probably not going to happen. Going to be like a week two weeks in between.

    Anything I can wipe it down with to slow the rust process for awhile? I am thinking phosphoric acid, is that a solution?
     
  2. GregCon
    Joined: Jun 18, 2012
    Posts: 689

    GregCon
    Member
    from Houston

    Are you sandblasting it or using plastic beads? Plastic will usually allow you longer. Worst is if you, or the blast guy, touches it anywhere after blasting - you'll see a hand print in a day.

    It also greatly depends how humid it is in your garage.

    No, acid won't help delay rusting.
     
  3. 117harv
    Joined: Nov 12, 2009
    Posts: 6,589

    117harv
    Member

    5 minutes or 5 months depending on where you live and the humidity. Yes the Phosphoric acid will help it keep until primer gets applied, it is not a substitute for primer and the primer should be applied ASAP.
     
  4. hotrod40coupe
    Joined: Apr 8, 2007
    Posts: 2,561

    hotrod40coupe
    Member

    Here in Vegas, it will last a year.
     

  5. DrJ
    Joined: Mar 3, 2001
    Posts: 9,419

    DrJ
    Member

    Here by the beach you can watch the rust grow within minutes.
     
  6. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    Well humidity is around 80% here, and I plan to use KBS coatings moisture cure epoxy.....

    I am not sure what type of media is used by the blasters.
     
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 56,074

    squirrel
    Member

    ....or five years.....
     
  8. Special Ed
    Joined: Nov 1, 2007
    Posts: 7,994

    Special Ed
    Member

    Just because you can't see it, doesn't mean oxidation isn't taking place. It starts as soon as it comes out of the booth. It's just a matter of degree....
     
  9. hotrod40coupe
    Joined: Apr 8, 2007
    Posts: 2,561

    hotrod40coupe
    Member

    KBS has a rust encapsulator, if you use that it won't make any difference.
     
  10. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,791

    tfeverfred
    Member Emeritus

    In Houston? 24 hours. Seriously.
     
  11. 117harv
    Joined: Nov 12, 2009
    Posts: 6,589

    117harv
    Member

    LOL...this is true, again depending on where you live and or store it. I have a 34 truck roof that has been blasted for about 2 years with no primer and still is 95% rust free.
     
  12. trbomax
    Joined: Apr 19, 2012
    Posts: 289

    trbomax
    Member

    Go to TSC and get a gal of evapo-rust. Put it in your spray gun and drench the parts, then let them dry. Here in northern mi,that will hold back the flash rust for a week or more.
     
  13. Boyd Who
    Joined: Nov 9, 2001
    Posts: 2,196

    Boyd Who
    Member

    I live in southern Manitoba where the summers can be hot and fairly humid. My frame was blasted well over a year ago and still shows no sign of any new rust. I consider myself lucky.
     
  14. Salty
    Joined: Jul 24, 2006
    Posts: 2,259

    Salty
    Member
    from Florida

    Here in Florida in the summer (and 15 min from the coast) your times are measured in hours.....worst I had was 2 hrs from the point I ground paint off till I noticed flash rust on top of it.....

    In the summer time I always cover my metal with Gibbs immediately after I'm done working with it.
     
  15. The37Kid
    Joined: Apr 30, 2004
    Posts: 30,778

    The37Kid
    Member

    Ever notice some guys can tough a freshly blasted panel and leave a hand print in 5 minutes? Stuff lasts around here for years without rusting. Bob
     
  16. Kiwi 4d
    Joined: Sep 16, 2006
    Posts: 3,579

    Kiwi 4d
    ALLIANCE MEMBER

    We stayed with friends in Truckee CA and he had model A patch panels still bare pressing 15 yrs old and barely perceptible hints of a thought of rust , this is in the mountains. Where as here in NZ mere mention of the word bare metal and rust is ready to begin.
     
  17. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    For some reason the rough surface that you get when you sandblast rusts faster than if the metal is ground shiny and smooth. It seems like the little hills and valleys catch moisture or somehow allow rust to form pretty fast.

    Here in Florida something that is sandblasted will start to exhibit a brownish tinge almost immediately, especially if he sand had some moisture to it. I have sandblasted something and by the time I got finished sandblasting the whole part the first area I did was starting to rust already.

    Don
     
  18. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,341

    29moonshine
    Member

    in west florida it will start over night. so i blast in the morning and prime that afternoon
     
  19. repeater
    Joined: Aug 20, 2012
    Posts: 60

    repeater
    Member

    When I completely sandblasted the body of my 50' Buick, it sat in a midwest garage 2 years and never got a speck of surface rust on it. Unless you live in the Southeast or the jungle, you don't have much to worry about.
     
  20. sumner41
    Joined: Oct 2, 2009
    Posts: 32

    sumner41
    Member

    metal prep and prime right away. metal prep is a solution that leaves a faint zinc chromate coating. It stops microscopic rust. Also SEAL primer with at least one coat of top coat (any color) as primer is POURUS. Actually dipping is best as it is a chemical action and rust formation is also a chemical action. But blasting will work. Make sure blaster has done cars before and get references. Blasting done wrong can cause problems. Also with sandblasting. sand will appear months after
     
  21. sumner41
    Joined: Oct 2, 2009
    Posts: 32

    sumner41
    Member

    unbeknown to most RUST starts on a MICROSCOPIC LEVEL. It is forming even before it can be seen with the naked eye
     
  22. GregCon
    Joined: Jun 18, 2012
    Posts: 689

    GregCon
    Member
    from Houston

    We all know rust starts on a microscopic level right away, but most of us also know it makes no difference. Rust on a scale that matters is what we are discussing.

    After all, the minute you are born you begin your path to death but no one let's that bother them.
     
  23. All one needs to know is rust never sleeps.:D
     
  24. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,966

    V8 Bob
    ALLIANCE MEMBER


    I used OXY-SOLV (sp?) years ago on fresh blasted metal. Not sure if it's still available. It needed only a water rinse, like soda, to be ready for prep/primer.
     
  25. 2935ford
    Joined: Jan 6, 2006
    Posts: 3,843

    2935ford
    Member

    High humidity...right now!
     
  26. Your in West Virgina,,,It will start within a couple of days if it's inside,,outside it will happen before your eyes! HRP
     
  27. Jimm56
    Joined: Aug 27, 2010
    Posts: 170

    Jimm56
    Member

    Optimist. :)
     

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