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Thread: Hot dipped galvanizing

  1. #1
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    Default Hot dipped galvanizing

    In the event that I can't find a suitable piece of hardware and have to forge my own, how could I galvanize it? I've used the cold spray paint type but it doesn't work very well. What if I melted a frying pan full of zinc and dipped the hot forging into it? Other than the obvious safety precautions, is there something else I need to know?

  2. #2
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    Default Re: Hot dipped galvanizing

    Yes, don't do it. There are several stages in prepping a part for galvanizing and the fumes given off by molten zinc aren't the best. Plus the massive safety hazard of having molten metal at waist height.
    Send it out to a galvanizers and let them worry about it.

  3. #3
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    Default Re: Hot dipped galvanizing

    IG Virginia
    3535 Halifax Road
    Petersburg, VA 23805
    Phone: (804) 733 0808
    Fax: (804) 733 2274
    http://www.ig-usa.com/ig-america-pla...-virginia.aspx


    Galvan Industries, Inc. (NC)
    PO Box 369 • 7320 Millbrook Rd
    Harrisburg, North Carolina 28075 • 704.455.5102 • Fax: 704.455.5215
    Toll Free: 1.800.277.5678
    http://www.galvan-ize.com/

    Tennessee Galvanizing (TN)
    P.O. Box 609 | Jasper, TN 37347
    (423) 942-1020
    http://tennesseegalvanizing.com/

    MetalPlate (AL, GA, FL,TX)
    1120 39th Street North
    Birmingham, AL 35234
    Phone: 205-595-4700
    http://www.metalplate.com/



    Valmont Coatings Empire Galvanizing (IL)
    10909 Franklin Avenue
    Franklin Park, IL 60131-1472
    847.455.0884
    http://www.valmont.com/galv/?id=179

    *************

    In 1742, French chemist Paul Jacques Malouin described a method of coating iron by dipping it in molten zinc in a presentation to the French Royal Academy. In 1836, French chemist Stanislas Sorel obtained a patent for a method of coating iron with zinc, after first cleaning it with 9% sulfuric acid (H2SO4) and fluxing it with ammonium chloride (NH4Cl).
    http://en.wikipedia.org/wiki/Hot-dip_galvanizing
    Last edited by George Ray; 06-08-2011 at 07:23 AM.

  4. #4
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    Default Re: Hot dipped galvanizing

    This thread brings up an issue I have been pondering 10 months now. I picked up a Holsclaw tilt trailer very cheaply for the NGH coquina I am building; perfect size and I really wanted to have the Holsclaw suspension (coil springs, shock absorbers, panhard rod etc.) to give a smooth ride for the boat on road trips. The steel of the trailer seems pretty sound throughout but not galvanized. I can disassemble the suspension components to get them individually media-blasted and galvanized but the main members of the frame are rectangular tube which precludes any reasonable way I can think of to clean the surfaces of the steel on the inside of the tubes prior to galvanizing. Does any one know of a way to successfully get something like this galvanized?

  5. #5

    Default Re: Hot dipped galvanizing

    Acme Galvanizing in Milwaukee, WI

  6. #6
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    Default Re: Hot dipped galvanizing

    There used to be a galvanizing firm in Ashland, VA. We had some fabricated parts treated there when I was working for the power company. Don't know if the firm still is in business but it might be worth a look.

  7. #7
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    Default Re: Hot dipped galvanizing

    There is more to it than just dipping. I believe the core of the steel needs to reach temp.

  8. #8
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    Default Re: Hot dipped galvanizing

    The Zinc isn't the big problem, It's the equal sized vat of Sulfuric acid (the flux) that is ugly.
    Our local Galvanizer charges very little for the service - maybe $50 per hundred pounds of Zinc with a $50 minimum. (that price is dated a bit)
    They have vats 60 feet long, 20 feet wide, and ten feet deep. One full of molten zinc and another full of acid. Their big contract is lighting poles, hence the 60 ft length.

    I routinely take complete boat trailers and have them dipped whole. Tow them up there, remove the axles in the parking lot and voila, off they go to the tank. Often I can't make the minumum weight and just add stuff from my household. All of our outdoor plant stands, garden furniture, and any other misc stuff is now galvanized (anchors and chain always need a freshening dip)
    It is a good economy.

  9. #9
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    Default Re: Hot dipped galvanizing

    Are these trailer frames tube or C- sections?

  10. #10
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    Default Re: Hot dipped galvanizing

    The basic structures are channel iron - ASTM A56 steel but there are some galvanized welded pipe "railings" or guides that bolt onto it.

    Galvanizers always look very carefully at tubing structures and often refuse them. The expansion of trapped gases in a tub of molten metal is bad news. Not to mention the acid that may be trapped in there. Then there is the problem of a tube filled with solid zinc.
    If you are planning a galvanized tubing structure you should consult with them first and they will advise you on where to drill vent and drain holes. This is according to how it will hang when it is lowered into the tank.

  11. #11
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    Default Re: Hot dipped galvanizing

    these two main structural members of the frame are ~ 3" x 2" rectangular tubes probably 10' long and open at the ends, everything else is some type of a C-section...

  12. #12
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    Default Re: Hot dipped galvanizing

    Yes, it's no big deal getting something galvanized. I had a new steel centerboard made for Drake about 6 years ago, and they sent it away and it came back perfectly coated. Didn't take long and didn't cost much.

    Hot-dipping isn't really a do-it-yourself thing.

    Dave

  13. #13
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    Default Re: Hot dipped galvanizing

    The last trailer I got galvanized cost me $200 AU about 12 months ago, that was a 14 footer. Any box sections need to have generous drain holes drilled in them. All galvanizing companies will prep your steel prior to galvanizing, so if you want it all done (descaling etc) just send it in as is. If you want to save money, get rid of as much rust as you can. They'll still ensure the metal is properly prepared before galvanizing, you just save some labour.
    The zinc also has to be passivated after dipping, I forgot about that.
    In Australia, galvanizing is charged at a certain amount per kg of metal deposited onto the job, so things like box sections are obviously more expensive to dip than C sections for example, which is another reason bot trailers aren't usually box sections.
    Anyway, I reckon $200 pick up and returned is a bargain for something the size of a boat trailer, especially for a coating that, if given even the most minimal maintenance (a quick hose down) will last another 30 years.

  14. #14
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    Default Re: Hot dipped galvanizing

    As mentioned above, galvanizers charge a minimum fee usually....something like $100 for 100 pounds of steel or less. So, get together several other items to get the weight up. Any other steel, anchors, mailbox posts, baby shoes, etc. I even contacted friends to see if they had something they might want galvanized or re-galvanized. Metal must have no finish on it, except if it has some old galvanizing.

    They charge a premium to galvanize chain.

    They don't often galvanize relatively dainty things like a masthead fitting, so you have to find someone in the plant you can talk to personally and get a feel if you can trust them. One shop broke my masthead fitting by bending (work hardening probably). Repaired it and found a different shop. Some shops specialize in smaller items and charge more per pound.

    Here's about 75 of my 100 pounds:


  15. #15
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    Default Re: Hot dipped galvanizing

    I have a Holsclaw 4 wheel trailer that I'd like to galvanize. Did you ever get yours done? If so, how'd it turn out and how much did it cost?

  16. #16
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    Default Re: Hot dipped galvanizing

    Not I, been using it as is, never dipped into salt water but often in fresh, so far so good, would love to get it galvanized at some point tho

  17. #17
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    Default Re: Hot dipped galvanizing

    Given the labor and cost of casting and finishing bronze, and the ease of welding steel and hot dipping it, there's a lot to recommend iron fittings for owner/builders. Galvanized (and painted, if you wish) fittings aren't "gold plater" quality, but they look fine if done neatly. I've seen a lot of larger vessels with painted galvanized iron fittings (sometimes painted dark brown as they would if they were bronze) and they look great.

  18. #18
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    Default Re: Hot dipped galvanizing

    Quote Originally Posted by levassor1 View Post
    I have a Holsclaw 4 wheel trailer that I'd like to galvanize. Did you ever get yours done? If so, how'd it turn out and how much did it cost?
    If it is built of Hollow Rectangular Section and pipe you must ensure that all of the sections can drain and vent to avoid explosion in the vat. You will haver to shot blast all of the old paint off of every part. Any threaded components will need to be protected as the galvanising will fill the threads.
    It really is quite difficult to build an ugly wooden boat.

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  19. #19
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    Default Re: Hot dipped galvanizing

    Quote Originally Posted by Dave Hadfield View Post
    Yes, it's no big deal getting something galvanized. I had a new steel centerboard made for Drake about 6 years ago, and they sent it away and it came back perfectly coated. Didn't take long and didn't cost much.

    Hot-dipping isn't really a do-it-yourself thing.

    Dave
    Hey Dave,
    Realize this is an old thread, but wondering where you had your centerboard galvanized.
    Mark

  20. #20
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    Default Re: Hot dipped galvanizing

    Quote Originally Posted by


    Valmont Coatings Empire Galvanizing (IL)
    10909 Franklin Avenue
    Franklin Park, IL 60131-1472
    847.455.0884
    [URL
    http://www.valmont.com/galv/?id=179[/URL]

    *************

    In 1742, French chemist Paul Jacques Malouin described a method of coating iron by dipping it in molten zinc in a presentation to the French Royal Academy. In 1836, French chemist Stanislas Sorel obtained a patent for a method of coating iron with zinc, after first cleaning it with 9% sulfuric acid (H2SO4) and fluxing it with ammonium chloride (NH4Cl).
    http://en.wikipedia.org/wiki/Hot-dip_galvanizing
    I just called Valmont and was told there is a $500 minimum, and no way through their organization to get in on another order. I was told that this is somewhat of a standard in the industry. I guess I will be doing Rustoleum. :-(

    Ken

  21. #21
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    Default Re: Hot dipped galvanizing

    Quote Originally Posted by kbowen View Post
    I just called Valmont and was told there is a $500 minimum, and no way through their organization to get in on another order. I was told that this is somewhat of a standard in the industry. I guess I will be doing Rustoleum. :-(

    Ken
    See if there are any fab shops near you who send stuff away and ask if they will add your steel to theirs.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
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  22. #22
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    Default Re: Hot dipped galvanizing

    I have had anchors redipped. I was able to add it to a commercial order. It was $10 for a 35 pound cqr.
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