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Technical Dow #7 coating ?????

Discussion in 'The Hokey Ass Message Board' started by porknbeaner, Dec 8, 2015.

  1. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,918

    porknbeaner
    Member

    Ok fellas here's the deal, I got some old Ansen Sprints. They are kind of rough and I am thinking about using Dow #7 on them. But I just read this on some product info.

    Application Notes:
    Castings containing bearings, studs, and inserts of brass, bronze, steel and
    cadmium-plated steel may be treated using this process. Note that aluminum
    inserts will be rapidly attacked by the Hydrofluoric acid present in the Type II
    activator.
    Use alkaline cleaners containing less than 2% caustic for ZK60A, ZK60B and
    some Magnesium Lithium alloys, as dimensional losses due to etching may occur.

    So my question is this and hopefully someone who actually knows as in has done it before knows.


    Can it be used on aluminum wheels and what results can be expected. I really don't want to go through the process of re-polishing the wheels that I have but I don't want to trash them either.

    Answers, conjecture or just pure BS welcome. Obviously answers would be better. ;)
     
  2. bowie
    Joined: Jul 27, 2011
    Posts: 1,903

    bowie
    ALLIANCE MEMBER

    If Dow7 doesn't work on aluminum , you could probably get them adonized to a similar hue.
     
    lothiandon1940 likes this.
  3. Rand Man
    Joined: Aug 23, 2004
    Posts: 3,371

    Rand Man
    Member

    The Dow 7 process works on magnesium metal only. You could have your Aluminum wheels powder coated in a similar color.
     
    lothiandon1940 likes this.
  4. CTaulbert
    Joined: Apr 8, 2007
    Posts: 1,024

    CTaulbert
    ALLIANCE MEMBER
    from Detroit

    I'm in the same boat as you. I have some aluminum wheels that I want a Dow 7 coating on. I've been researching it for a few months, in hopes of finding a comparable coating for aluminum.

    For those who say powder coat, it doesn't capture the essence of Dow 7, which is pretty transparent. Anodizing would probably be too opaque.

    I'm all ears for anyone who has pulled off a similar looking coating....
     
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  5. RichFox
    Joined: Dec 3, 2006
    Posts: 9,541

    RichFox
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    At UA we used Dow on Magnesium. We used Alodine on aluminum for much the same thing.
     
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  6. Russco
    Joined: Nov 27, 2005
    Posts: 4,018

    Russco
    Member
    from Central IL

    There was a thread on this a few years back someone is or was making aluminum wheels with a coating that looked similar to DOW7 I think its Alodine but they are pretty pricey I was wanting to try some wheels with Alodine and see but havn't got to it yet.
     
  7. Russco
    Joined: Nov 27, 2005
    Posts: 4,018

    Russco
    Member
    from Central IL

  8. Hot Rods Ta Hell
    Joined: Apr 20, 2008
    Posts: 3,762

    Hot Rods Ta Hell
    Member

    Beaner posts on every thread so that may have been 5000 posts ago...:rolleyes:
    Possibly a custom mixed clear powder coat, but those "rough" Ansen's will have to be cleaned up pretty good before coating. Dow 7 is a tricky colored finish to duplicate.
     
    scotty t likes this.
  9. Russco
    Joined: Nov 27, 2005
    Posts: 4,018

    Russco
    Member
    from Central IL

    This is the Real Rodders version. I've been wanting to try Alodine to see if it will produce similar looking results but it may take some experimenting with solution strength and soak times maybe. Then again it may be a totally different process they are using.
    dow7.jpg dow 7.jpg
     
  10. CTaulbert
    Joined: Apr 8, 2007
    Posts: 1,024

    CTaulbert
    ALLIANCE MEMBER
    from Detroit

    I'm pretty sure they're doing some type of powder coat.

    I bought some alodine a couple weeks ago, and haven't had the time yet to do some controlled experiments for length of exposure, methods, for the application. I did do a quick test on a piece of aluminum that I brushed on one end, and blasted on the other, and the initial results were very promising.

    I think to do multiple pieces consistently (wheels), a bath dip would be easiest.
     
  11. DDDenny
    Joined: Feb 6, 2015
    Posts: 11,400

    DDDenny
    Member
    from oregon

    Beaner
    I always liked the look of Halibrands with the Dow 7 coating, just couldn't put the money together for them. Second best thing was a used set of Ansens and four cans of Krylon.
    Put this car together in early 70's right out of high school. Sorry for the old photo.

    [​IMG]
     
  12. junkman8888
    Joined: Jan 28, 2009
    Posts: 418

    junkman8888
    Member

    Greetings! Guy around here had a set of aluminum wheels shot-blasted (for texture) and then titanium powdercoated, looked amazingly close to magnesium/Dow7.
     
  13. bchctybob
    Joined: Sep 18, 2011
    Posts: 1,539

    bchctybob
    ALLIANCE MEMBER

    When I worked in aerospace we used brush-on Alodine as a final coating when we had to drill or machine an aluminum part that was already assembled onto the next assembly. I think the process was; wipe w/Isopropyl alcohol, wipe w/ D.I water, another alcohol wipe and then apply the Alodine. It was a similar color to Dow 7 in the bottle but changed the aluminum color very little in two coats.
    I would sure give it a try on a spare aluminum wheel. Try it on a clean polished part, a scotch-brited part, and a sand/bead blasted part and see what happens. Try multiple coats and different methods of application (wipe, brush or spray). Near as I can remember it stains everything it touches and may permanently stain a wheel so test on something you don't care about.
    Sorry but paint always looks like paint and powder coat always looks like powder coat - Alodine is a conversion coating for aluminum. Read about it here; http://www.evroberts.com/EVRTDS/30748/Alodine 1200S Brush Process_tds.pdf
     
  14. alchemy
    Joined: Sep 27, 2002
    Posts: 13,587

    alchemy
    Member

    Alodine 1201 should provide the goldish color. Alodine 1001 should be clear (on aluminum). For even application, you will definitely want a big bucket full to dunk the whole object at once.
     
  15. metlmunchr
    Joined: Jan 16, 2010
    Posts: 721

    metlmunchr
    Member

    I've made some machined parts in the past that required Alodine. I followed the recommended procedure which is to first etch the parts with Alumiprep then rinse with water and then apply the Alodine. IIRC, the Aluumiprep is diluted with 2 parts water to 1 part of the chemical to make a 10% solution. As purchased, the Alumiprep is a 30% solution. Couple minutes in that and then into the Alodine for a couple more minutes after the rinse. Parts came out with a nice even color coat.

    I tried just the Alodine on some clean aluminum without the pre-etch, and it didn't color all that well. Also found it was pretty easy to scratch thru the color when applied like that, sorta like it had just left a coating of dye on the surface.
     
  16. alchemy
    Joined: Sep 27, 2002
    Posts: 13,587

    alchemy
    Member

    Yes, Alodine is not meant as a final coating. It is just a conversion in prep for another finish. At least the kind I used before.
     
  17. metlmunchr
    Joined: Jan 16, 2010
    Posts: 721

    metlmunchr
    Member

    True. Similar to using Metalprep or other phosphoric acid treatments on bare steel to produce an iron phosphate coating. The parts I made got some sort of additional coating but it was handled by either the customer or some outside supplier they used.

    One other caution with Alodine. While it might be tempting to use a cheap spray gun to apply the chemical to a wheel rather than buying enough product for dipping, Alodine is chromic acid and contains hexavalent chrome. That's some seriously wicked stuff that you wouldn't want to have floating around in the air anywhere near humans or pets.
     
  18. I'm amazed that you can even buy Alodine for personal use.

    Here it is considered very cancerogenic and will destroy the water supply in 6 counties if poured out.
     
    Charlie Chops 1940 likes this.
  19. dreracecar
    Joined: Aug 27, 2009
    Posts: 2,691

    dreracecar
    Member
    from so-cal

    Hydrodipping if there is sutible color available
     
  20. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,918

    porknbeaner
    Member

    Thanks for the replies.

    on that old thread I probably posted before reading about the problems with aluminum. I already own the wheels so it would just be the cost of coating not like buying new wheels.

    I am going to look closely at it and see what can be done with it. ;)
     
  21. wrenchbender
    Joined: Sep 5, 2007
    Posts: 1,664

    wrenchbender
    Member

    Hey beaner I have been doin a bit of research on the alodine deal and I think I will try some it seems it will be a close second to Dow 7 mag. And best part is it's not that expensive also I have been told it needs to be washed rinsed and dried with alumni prep 33 before using the alodine and to get the gold coloring need to use #1201 this info coming from a trusted friend in the aerospace industry according to him the durability is good but like any coating it can be scratched but under most circumstances it will be fine
     
  22. tjet
    Joined: Mar 16, 2009
    Posts: 1,270

    tjet
    Member
    1. Early Hemi Tech

    Last edited: May 16, 2019
  23. gnichols
    Joined: Mar 6, 2008
    Posts: 10,404

    gnichols
    Member
    from Tampa, FL

    ^ Too bronze for me.
     
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  24. gnichols
    Joined: Mar 6, 2008
    Posts: 10,404

    gnichols
    Member
    from Tampa, FL

    When I think of painted mags, I mostly remember oval track wheels. They took a beating and got painted all kinds of colors, white thru to red. Why not try a custom blended, gold-mist-ish base coat and then a clear satin? Gary
     
  25. pirate
    Joined: Jun 29, 2006
    Posts: 187

    pirate
    Member
    from Alabama

    I wrote the following in another post. The problem with chromate conversion coatings is its very sensitive to slight differences in the surface finish of the metal and also slight differences in the bath itself. So the color may or may not be repeatable and may vary from a light yellow to a dark bronze.

    I think the gold tint you are talking about is Alodine also know as Iridite or Yellow Iridite. These are all chromate conversion processes. Cast aluminum and especially cast magnesium corrode very easily in air. The corrosion layer actually protects the surface from further corrosion and depending on you opinion can look great or terrible. Alodine (chemical conversion) is a chemical process where the wheels are dipped in a acid/chemical salt bath and the surface forms a rather hard layer (but not thick) that protects the surface from corrosion. The process imparts a gold color that can be very dark to a light hue depending how long the metal is left in the bath. The Alodine process was used extensively on aircraft parts decades ago and still used today. Alodine, Iridite or Yellow Iridite are all trade marked names however chromate conversion is the commonly used industrial name.

    Anodizing is another chemical process used to protect aluminum and provides a longer lasting coating and can be made just about any color you would ever want.

    However for your application paint or powder coat is probably the most practical. Powder coat can be just about any color and would be much more durable then Alodine (chromate conversion).
     
    CudaChick1968 and lurker mick like this.

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