Coating bare steel with antifouling paint

Discussion in 'Metal Boat Building' started by RayThackeray, Jan 7, 2013.

  1. RayThackeray
    Joined: Apr 2011
    Posts: 147
    Likes: 12, Points: 0, Legacy Rep: 90
    Location: Alameda, CA, USA

    RayThackeray Senior Member

    See this datasheet. Rustoleum have written to me to confirm (THREE TIMES!) that this antifouling paint can be applied to bare steel. I repeat, BARE STEEL. The instructions simply say "Remove all loose rust or deteriorated coatings by scraping or wire brush."

    http://www.rustoleumibg.com/images/tds/CBG_Anit_FoulingPaint.pdf

    Ray
     
  2. RayThackeray
    Joined: Apr 2011
    Posts: 147
    Likes: 12, Points: 0, Legacy Rep: 90
    Location: Alameda, CA, USA

    RayThackeray Senior Member

    PRODUCT DESCRIPTION

    Rust-Oleum Marine Coatings 1 qt. Flat Black Bottom Antifouling Paint provides a handsome and practical solution to prevent the buildup of marine growth below the waterline. This paint releases copper and can be applied to fiberglass, wood or steel surfaces in fresh or saltwater situations. This paint can be applied over hard antifouling coats but soft antifouling coats should be removed.


    For use below the waterline in fresh or saltwater environments
    Flat finish offers a subtle appearance
    Cover up to 85 sq. ft. for ideal use
    Can be applied over hard antifouling coats but not soft antifouling coats
    Apply to wood, steel, fiberglass and any non-aluminum trailer boat
    Releases copper to prevent the buildup of barnacles, algae and other marine growth in mild to moderate fouling conditions
    Subject to or will include a recycling fee in the following states: CA, OR
    Actual paint colors may vary from on-screen and printer representations
    MFG Brand Name : Rust-Oleum
    MFG Model # : 182821
    MFG Part # : 182821
    Return To Top
    SPECIFICATIONS

    Application Method Spray, Roller or Brush Assembled Depth (in.) 8 in
    Assembled Height (in.) 8 in Assembled Width (in.) 8 in
    Color Black Color Family Blacks
    Container Size 1 QT-Quart Coverage Area (sq. ft.) 85 ft²
    Exterior Paint & Stains Product Type Pool Paint Low Temperature No
    Manufacturer Warranty Satisfaction Guaranteed Number of coats recommended 2
    Paint Base Epoxy Paint Product Type Exterior Paint/Stain
    Paint Type Epoxy Pool Paint Base Epoxy
    Primer Required No Returnable 90-Day
    Sheen Flat/Matte Skid Resistant No
    Surface Use Yes Time before recoating (hours) 4
    UV Resistant Yes Water Compatibility
     
  3. rick gray
    Joined: Dec 2012
    Posts: 87
    Likes: 4, Points: 8, Legacy Rep: 30
    Location: port coquitlam B.C.

    rick gray Junior Member

    anti fouling coatings

    excellent info!! does anyone know what products to use on bare aluminium hull below water line?
     
  4. tazmann
    Joined: Aug 2005
    Posts: 329
    Likes: 17, Points: 18, Legacy Rep: 215
    Location: California

    tazmann Senior Member

    Ray
    I wouldn't use it direct on steel, copper and steel is not a good mix? a good barrier coat first to isolate
     
  5. keysdisease
    Joined: Mar 2006
    Posts: 794
    Likes: 43, Points: 28, Legacy Rep: 324
    Location: South Florida USA

    keysdisease Senior Member

    While Rustoleum certainly has plenty of experience coating steel, this just sounds wrong.

    Copper and steel are both conductive, and salt water is an excellent electrolyte. What your describe sounds like it would make enough electricity to run your boat. There must be a reason all the other paint manufacturers recommend a barrier coat on steel before using a copper based paint.

    Ask Rustoleum if they will cover the cost of re-plating your boat below the waterline when electrolysis eats it until its as thin as tin foil. I'll bet their warranty is for replacement of defective materials only and they assume no liability for other damages.

    Steve
     
  6. Landlubber
    Joined: Jun 2007
    Posts: 2,640
    Likes: 124, Points: 0, Legacy Rep: 1802
    Location: Brisbane

    Landlubber Senior Member

    does anyone know what products to use on bare aluminium hull below water line?

    I use Altex/Devoe whatever they call themselves today, excellent products for protective coatings and antifouls.

    http://www.altexboatpaint.com/
     
  7. RayThackeray
    Joined: Apr 2011
    Posts: 147
    Likes: 12, Points: 0, Legacy Rep: 90
    Location: Alameda, CA, USA

    RayThackeray Senior Member

    BUT - - an analogy is that just a few years ago a doctor eradicated stomach ulcers overnight by prescribing a strong antibiotic, something nobody before ever tried.

    Could Rustoleum have discovered that this simply works? The paint is an epoxy-based copper anti-fouling. They actually went out of the way - and IN WRITING - to me to say that primer is not required.

    I may actually go with this advice, and just monitor the bottom frequently, as an experiment - and if it doesn't work, I have a strong case that Rustoleum must cover the cost of re-coating with an alternative, because of their advice.
     
  8. tazmann
    Joined: Aug 2005
    Posts: 329
    Likes: 17, Points: 18, Legacy Rep: 215
    Location: California

    tazmann Senior Member

  9. keysdisease
    Joined: Mar 2006
    Posts: 794
    Likes: 43, Points: 28, Legacy Rep: 324
    Location: South Florida USA

    keysdisease Senior Member

    Good call Tazman, from the label:

    STEEL HULLS, UNDERWATER METAL PARTS, LEAD KEELS: Contact
    Rust-Oleum Technical Services for complete priming instructions

    Rust-Oleum shall not under any circumstances be liable for incidental or consequential damages. By purchase or use of this product, buyer agrees that the sole and exclusive remedy, if any, is limited to the refund of the purchase price or replacement of the product at Rust-Oleum’s option.


    Yes, I know they told you in writing you don't need a primer. Use at your own risk.

    And I got a kick out of "Cuprous Oxide 45.7%" being called "heavily loaded with cuprous oxide"

    Steve


     
  10. MikeJohns
    Joined: Aug 2004
    Posts: 3,192
    Likes: 206, Points: 63, Legacy Rep: 2054
    Location: Australia

    MikeJohns Senior Member

    Ray

    There are standards for paints. There's no way this type of antifouling can properly protect your hull. Looking at the MDSS for the product it's just a run of the mill single pot antifouling formulation. I't not a fancy new product and in the paint matrix any Rosin slowly dissolves releasing fresh copper toxin.

    Sure it will stick to bare steel but it's most likely that they mean small patches of broken down coating. I suspect whoever is contact you is themselves a bit confused about required practice.

    You would be remiss not to coat the steel first, and get several good coats of 2 pack, say a polyamide cured salt water immersable epoxy to around 200 microns ( at least 150) . Then apply the antifouling.

    There is no such thing as a free lunch.
     
  11. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 115, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    Never heard of rustoleum antifoul.

    Locally The Budget conscious bare boat charter fleets use mid range Jotun antifoul. Good paint. Apply it over properly primed surface. Purchase it in 20 litre bucket.
     
  12. CDK
    Joined: Aug 2007
    Posts: 3,324
    Likes: 147, Points: 63, Legacy Rep: 1819
    Location: Adriatic sea

    CDK retired engineer

    The 'Rust-oleum' product contains copper as an oxide, so it does not conduct and there is no risk of electrolysis. That is the good news!

    The bad news is that almost 50% of the "paint" is not epoxy but a metallic oxide that slowly dissolves in seawater. Over time, that leaves you with a coating full of holes, exposing bare steel to the environment.

    Guess what happens......
     
  13. El_Guero

    El_Guero Previous Member

    NO. Galvanic corrosion.

    http://geminimarinesurvey.com/yahoo_site_admin/assets/docs/Marine_Metal_Corrosion.325111027.pdf

    Yes. The paint should corrode before the hull .... But, that is up to you.

    And free advice is good for what you paid for it - I don't think they would cover your experimental use of their product.
     
  14. El_Guero

    El_Guero Previous Member

    From your pdf:

    "suitable for all Non-Aluminum trailered boats."

    I think that means do NOT get the boat wet.

    :D

    Sounds like better than average anti-fouling paint? But, it admits in the directions it has limits.
     

  15. RayThackeray
    Joined: Apr 2011
    Posts: 147
    Likes: 12, Points: 0, Legacy Rep: 90
    Location: Alameda, CA, USA

    RayThackeray Senior Member

    A bit of a laugh, huh? Rustoleum actually got back to me and retracted the advice! They are a good bunch and make great paints, we use Rustoleum here with great results all over the boat. In fact, for the price here we couldn't beat Rustoleum's antifouling paint so will be using it - but for the antifouling coat above steel primer and paint!
    Cheers, Captain Ray
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.