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Cleaning Steel Prior to Painting?

Discussion in 'Electronic Design' started by Jim Thompson, Jul 4, 2007.

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  1. Jim Thompson

    Jim Thompson Guest

    When I put out the flag today I noticed that the steel wall bracket is
    rusting, in spite of this being Arizona, where rust is forbidden ;-)

    Do I remember correctly that cleaning steel in a mild acid solution is
    the best treatment to remove the rust, then prime and paint?

    ...Jim Thompson
  2. Tim Wescott

    Tim Wescott Guest

    You want phosphoric acid, IIRC. It's the stuff in Naval Jelly, at any
    rate. It cleans the rust and leaves a mild, paintable, anti-corrosion
    film behind.


    Tim Wescott
    Wescott Design Services

    Do you need to implement control loops in software?
    "Applied Control Theory for Embedded Systems" gives you just what it says.
    See details at
  3. D from BC

    D from BC Guest

    You could try a wire wheel on a drill..
    The link is just an example....
    D from BC

  4. Ospho

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  5. MooseFET

    MooseFET Guest

    I've heard that oxalic acid is better.

    This is also claimed to work:
  6. Guest

    Phosphoric acid apparently passivates the surface. From the point of
    view of removing oxidised iron, oxalic acid might be better - oxalic
    acid forms a very stable complex with ferric ions, so the
    electrochemical potential pulling the ferric ions into solution is
    very high.

    I never found that passivating old rust did very much good - the
    approach that worked best for me over the long term involved getting
    rid of as much of the rust as possible, with a wire brush followed by
    coarse emery paper to leave a reasonably bright surface, which I then
    protected with a coat of zinc-rich primer (paint loaded with particles
    of metallic zinc) followed by a coat of regular primer. The zinc
    particles presumably act as sacrificial electrodes, and seem to keep
    the iron rust free for many years.
  7. Barry Lennox

    Barry Lennox Guest

    I'd use a flap wheel or sanding disk to remove 90% of the crap. Maybe
    a slosh over with phosphoric acid or one of the off-the-shelf
    versions, then a coat of "Hammerite" works wonders. Limited colors,
    but it's pretty tough.

  8. Mick

    Mick Guest

    Kill rust?
    Mick C
  9. John Ferrell

    John Ferrell Guest

    If it has not reached the flaking point Rustoluem spray paint will do
    just fine. Follow the instructions on the can. It will take at least
    overnight to dry. If it has reached the flaking point mechanical
    removal of the rust is advised!

    John Ferrell W8CCW
    "Life is easier if you learn to
    plow around the stumps"
  10. Rich Grise

    Rich Grise Guest

    This sounds kinda kewl:

  11. default

    default Guest

    On Wed, 04 Jul 2007 01:19:37 -0700, wrote:

    I agree with that. I never had much success with Naval Jelly or
    Oxalic acid (also used to clean/dissolve wood) or "Extend." Best way
    is do the work of removing the rust then prime with zinc primer then
    paint with a high quality oil base paint (if you can still find it)

    Incidentally, the two techniques priming and passivating aren't
    necessarily compatible. Small amounts of residual acid play havoc
    with zinc primers.
  12. HapticZ

    HapticZ Guest

    try a litre of classic coca cola

    it erodes everything, including teeth.
  13. I second the navel jelly. Then Murtic acid for heavy jobs ;)

    BTW, use rustolium and their primer. If not I really like the Painters Touch
    paint, really good UV protection.

  14. Joerg

    Joerg Guest

    Good man. We went to a parade today, out in the boonies. Scouts,
    farmers, tractors, horses and so on. Then the Weber was fired up.
    Country living is good. But after a parade with lots of horses it does
    smell a bit ....

    I'd go with John's advice. Brush off any coarse stuff with a wire brush,
    then a fresh coat of your favorite color Rustoleum. Ace has some good
    stuff as well. Initially I thought that there is no free lunch when it
    comes to rust but my wife convinced me. She regularly spray-paints
    rusted lawn chairs and afterwards the paint lasts years. And this is
    Cahleefohniah where is does rain and freeze and all that.
  15. Jimmie D

    Jimmie D Guest

    By a vinyl holder. Wife picked up 2 for less than $2 ea. Otherwise remove
    the rust mechanically, finish up wiht some naval jelly, prime and paint.

    Not worth the two bucks to me.
    When mine doesnt have a flag in it it holds a support for hanging flower
  16. mpm

    mpm Guest

    I could say that the rust is indicative of the current general state
    of affairs in the nation, and that maybe the rust and the locality are
    somewhat unrelated....

    But I think that might just annoy Jim, and somehow, I'm already on his
    "bad" side.. :(

    Instead, I will tell you something I learned from my brother the other
    day that I totally did not know. --
    US Flags with Gold Fringe around the edges appearently means that
    maritime law is practiced wherever it is on display.
    I have to research this further to make sure he got it right, and that
    my 3rd or 4th hand interpretation is right.

    I need to know this so next time I'm in Virginia paying one of those
    $3K speeding tickets, I can ask them to go get a real flag before I
    accept the verdict (...unless I'm speeding in my boat, that is.)


    Oh: For a flag holder, I would think just about any "treatment" would
    last a suitably long time, unless you're passing this on to the
    grandchildren or something... Or ditch it and get one made of solid

  17. Come on. Everyone knows that Jim prefers solid gold.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  18. g

    g Guest

    I would just watch it rust. Might take a while.

    The one thing thats best to do after prep, is use a self etching
    primer. You have to do this when painting a car as I have done several
    times, otherwise rust will form and creep.

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