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Stripping paint off tank

Discussion in 'Tanks, Valves & Bands' started by BassO, Oct 17, 2020.

  1. CuzzA

    CuzzA Percoidea Wetwork for Hire ScubaBoard Supporter

    18,990
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    Bead blasting would be my choice and in the absence of using a two part marine paint and primer I would buy a pint of alkyd enamel paint, thinned with xylene and add Majic Hardener catalyst. Prime it and spray several coats with a HVLP 1.4 tip gun. The catalyst will increase hardness, gloss and curing time significantly. As fast as finger nail proof in 24 hours at 70°f. I find the rattle can formulas are not what they once were. The paint is soft and the curing time can take weeks, if not months.
     
  2. Nathan Doty

    Nathan Doty Contributor

    321
    287
    I'd do that for $11. I spend 7 or 8 on a can of cold zinc and only get 2 tanks out of it. $11 without the work, done deal IMO.
     
    rjack321 and Lostdiver71 like this.
  3. Ulfhedinn

    Ulfhedinn Divemaster Candidate

    # of Dives: None - Not Certified
    Location: So CAL
    689
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    Any reason you couldn't just bead blast my steel72s and leave them clean of paint?
     
  4. happy-diver

    happy-diver Skindiver Just feelin it

    # of Dives: 2,500 - 4,999
    Location: Same ocean as you!
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    No reason if you enjoy orange-brown hues all over all your stuff
     
    Eric Sedletzky and Lostdiver71 like this.
  5. Ulfhedinn

    Ulfhedinn Divemaster Candidate

    # of Dives: None - Not Certified
    Location: So CAL
    689
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    yep..that is what i thought.
     
  6. happy-diver

    happy-diver Skindiver Just feelin it

    # of Dives: 2,500 - 4,999
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    Spray a few coats of clear on it man
     
    Ulfhedinn likes this.
  7. Eric Sedletzky

    Eric Sedletzky Contributor

    # of Dives: 500 - 999
    Location: California
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    If money is no object and you want the best possible coating system on earth then go with Awl Grip Marine paint system.

    You have to strip the tanks, best done using fine mesh sand (60) or bead blast all paint off. You can’t use Awl Grip over anything that is inferior because your paint job is only as good as what you put it over. Left over galvanizing is fine is there is any left over.
    Prime with Awl Grip 545 Epoxy 1:1 primer.
    Top coat with Awl Grip linear polyester urethane topcoat.
    It’s a 1:1 catalyst-paint ratio and some reducer. They also have an accelerator for it otherwise it’s a 12 hour to touch cure at 70 degrees. 24 hours to recoat with no accelerator without sanding.
    Without boring you to tears with all sorts of technical jargon, it’s simply the toughest paint out there used on ocean yachts, guaranteed at least 10 years sea life before it even begins to lose gloss or fade, That’s hot sun plus reflected sun off the water, wind, salt, rubbing against docks with fenders etc. and all the other stuff the ocean going vessels go through. Besides hull sides It can be used on floors, decks with extremely good scuff resistance. I believe original factory painted scuba tanks were painted with a linear polyurethane of some brand.
    Awl Grip also has a special rolling/brushing catalyst and reducer for their topcoat. I have painted many 40’ 50’ sailing yachts this way when I had my marine business.
    The epoxy primer can also be rolled or brushed on.
    Important!: read all the directions because this stuff is very technical. It’s also very toxic so be very careful.
    For professional use only.
    After sand or bead blasting and refinishing any scuba cylinder it needs to be re-hydro’d.
     
  8. happy-diver

    happy-diver Skindiver Just feelin it

    # of Dives: 2,500 - 4,999
    Location: Same ocean as you!
    2,249
    1,469
    Spray a few coats of clear on it man with Awl Grip Marine paint system.
     
    Eric Sedletzky likes this.
  9. Kensei

    Kensei Master Fin Sharpener ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Palos Verdes, CA
    193
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    I have a galvanized tank that someone painted. I stripped off all of the paint which also took off some of the galvanizing. I sprayed it with ZRC Galvilite. I'd like to put a protective clear-coat over the Galvilite. Regarding topcoating, ZRC says:

    TOPCOATING: After 24-48 hours, ZRC may be topcoated with acrylic, chlorinated rubber, epoxy, urethane or vinyl type products. DO NOT TOPCOAT WITH ALKYD, ALKYD-MODIFIED ACRYLIC, OR LACQUER TYPE PRODUCTS.

    Do you have any suggestions for a good clear coat to go over the Galivilite?
     
  10. Eric Sedletzky

    Eric Sedletzky Contributor

    # of Dives: 500 - 999
    Location: California
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    If you used a cold galvanizing spray then that is the topcoat. You should not have to put anything further over it. The zinc dust in the binding film is the sacrificial metal that corrodes instead of the steel. That’s how it’s designed.
    If you use an epoxy primer /topcoat system instead of a sacrificial zinc system, the idea is that the epoxy provides a waterproof and therefore oxygen transfer proof coating that will lock in any rust and also prevent any oxygen from transferring through to initiate corrosion. Therefore the surface of the steel is held in limbo that can’t continue to rust or start new rust, unless the coating is breached. With the zinc system, if the coating is breached then corrosion will only be present where the actual steel is exposed and no further. With the epoxy primer system if the surface is breached the corrosion could technically crawl under the coating because it will not sacrifice itself as a less noble metal. However, since epoxy grips to steel so well and forms an incredible bond this phenomenon is somewhat minimized.
    Powdercoating is tough on the surface but rust can develop underneath and form corrosion bubbles that are sometimes hard to detect because the Powdercoating film is thick and can hide underlying problems. The rust can creep and it can get really bad, especially on aluminum. I think Powdercoating on items that are going to be immersed in salt water is a really bad idea.

    Epoxy has a very fine molecule structure that will not allow water to pass through plus it’s long chain structure is also very strong and forms “legs” or tentacles that grip into every nook and cranny of the steel at a microscopic level.
    The old Etch primers are a thing of the past as the acid converters have been discontinued and the one part new stuff is basically crap and doesn’t really etch into anything.
    Epoxy is far superior in every aspect as a DTM primer (direct to metal) if you want a shiny topcoat color choice.
    The topcoat is simply a color coat for gloss, durability, and long term UV resistance. Epoxy barrier coats / primers need to be top coated to be UV resistant and completed as a system. Epoxies by themselves are not UV resistant.
    Clear coating over a zinc coating would be kind of awkward at best and I couldn’t guarantee the long term results. If you want a shiny grey finish then use shiny grey paint over the proper primer.

    There’s nothing wrong with zinc coating, it works great and I don’t mind the dull variegated grey industrial look.
    Cold galvanizing steel and leaving it is a totally legit system. I have a chunk of steel I sprayed cold galvanizing zinc on as a test and put it on my fence. It’s still holding up great going on 3 years now outdoors in the open sun and rain.
     
    rob.mwpropane, Kensei and Bob DBF like this.

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