steel hull protection paints epoxy ?

Discussion in 'Materials' started by tugboat, Jan 26, 2012.

  1. dougfrolich
    Joined: Nov 2002
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    Location: San Francisco

    dougfrolich Senior Member

  2. pauloman
    Joined: Jun 2010
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    Location: New Hampshire

    pauloman Epoxy Vendor

    all coal tar epoxies are not the same. vary widely in quality. Also they are being phased out. see www.epoxyproducts.com/coaltar.html. There are modern replacements like CM 15 epoxy paints.

    you use a thixotrophic epoxy paint not a raw marine resin system and you don't need to add thixo fillers.

    epoxies are generally a protective anti corrosion coating (you can also add MIO to your coatings - common in europe) - you then topcoat with bottom paint, copper epoxy, etc. or enamel, latex or lpu above the waterline.

    paul oman progressive epoxy polymers inc.
     
  3. mastcolin
    Joined: Jun 2005
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    Location: The Netherlands

    mastcolin Senior Member

    You can go shopping for food ingredients and so can a michelin starred chef. You won't make the same food.

    In a way you are right. Epoxy paint is "just" some sort of epoxy and some sort of amine and some sorts of various powders. The problem is the "chemistry"/ paint science which you can't escape from no matter how much you want to.

    1) the amount of powder you add makes massive effect on properties. Look up "pvc" (pigment volume concentration)
    2) you won't be able to easily mix the powders properly
    3) the powders you are talking of adding are pretty useless for any big benefits.
    4) the resins you will want to use will probably not be ideal for a paint
    5) you'll probably end up with a paste which you won't get to flow out/wet-out
    6) doing a test on a panel and looking at it after a few days (weeks...months) isn't the same as putting it on your boat. You willing to take risk that it falls off after a year...5? And it will probably happen.

    Try to find a commercial dealer who sells to fishing boats or similar. They sell "cheap" epoxy designed for marine use. Why re-invent the wheel? The time you are investing in prep and the time you will waste trying to make something. even if it did work isn't worth risk in my eyes.

    ps not sure about your idea of oiling the plates after prep and storing them. How are you going to get the oil removed? The surfcae will be very rough. You can't rub it with rags. The burrs snatch all the fibres from the rags and you will them be painting a fuzz.

    Better idea is just to weld everything together then grind/blast and paint. You can do it in sections if need be.

    As suggested, get in contact with a supplier. They have helpdesks/websites. Speak with International, Jotun, Hempels, Ameron (sorry for the US bias). They will guide you.

    Don't forget there are also 1 pack options. Cheaper than epoxy, sometimes more forgiving to machine prepped steel (ie not sand blasted). These 1packs will be much better than anything you mix up in your shed. And you will get a basic warranty with them as well.
     
  4. pauloman
    Joined: Jun 2010
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    Location: New Hampshire

    pauloman Epoxy Vendor

    really tough, abrasion resistant epoxy coating is usually handmade by adding fine quartz sand into the epoxy.

    paul
    progessive epoxy polymers inc.
     
  5. soghol
    Joined: Dec 2011
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    Location: lbj Indonesia

    soghol New Member

    I've seen few epoxy application where the mixtures and the apllication area are pretty unusual;
    -On the hull (above water, impact side) and main deck of a fiberglassed (polyester resin) surface of a wooden boat, 1 litre of acrylic paint mixed with pre-mixed epoxy resin+hardener mixture. My colleagues said the amount of pre-mixed epoxy must still allows the use of paint brush. So im guessing it's a little bit thicker since the acrylic paint alone without thinner added already pretty thick. And the pot live was very short, around 15 minutes. Longer than that the epoxy mixture emulsify at the bottom of the mixing pot, separated itself from the paint.
    The result; for the deck its still great, but very2 slippery, while the hull is pretty much the same, still very hard surface, protects the side from scratches while at the pier or most of the time at the mooring site alongside 2 other smaller boats. Already been more than 5 years for the deck, and 3 years for the hull sides.

    -On a steel rudder, covering few weld joints farthest to the rear, where corrosion/pitting (or maybe cavitation?) often target those area. I was trying to pry it open so i can paint it with antifouling paint, but were only able to remove few area which were already delaminated, the rest were still stick to the surface pretty good. The mixture was epoxy mixture thickened with talk. Didn't remember exactly when they did this.

    There are few other examples that i dont care to mention. As far as i remember, we never use any marine specific coatings (except the antifouling which cost under $10/liter, like most other coatings/paint), so this 'experiment' is quite common in my country (mixing antifouling paint with liquid insect killer), etc.
     
  6. sabahcat
    Joined: Dec 2008
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    Location: australia

    sabahcat Senior Member

    My thoughts as well
    Even better if there are pictures of Oil rigs, tankers and undersea pipelines on the tin.

    Stay away from the ones with pictures of shiny mega yachts on them as these will cost you extra.;)
     
  7. tugboat

    tugboat Previous Member

    Hi Mastcolin--yes i see the light after researching it a bit more--i did find some pettit products that seem to be not very expensive for my needs--looking at around 400.00 for the whole hull primed and painted...
    west marine has the products i need--i guess i was panicking because i thought it was going to run into the thousands...but thats not true..
    anyway the interlux and pettit companies have exactly what i need for relatively cheap ...i do plan to grind the plate myself and prime as i go...ill use a 7 inch grinder and some 30 grit sand paper which is supposed to last 3 x's longer than regular paper...
    the boat is flat bottomed and there really isnt that much surface area. by the time i rent a blaster, have it done, pay for sand, move the sand, get set up--ill have ground down my entire hull for 1/10th the price...in the future ill have it professionally done when funds are higher- but this should last a couple years till then,....
     

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  8. tugboat

    tugboat Previous Member

    Thanks for the input-- it does seem this looks expensive...in time ill get it all done right but i have a time frame and have to meet it with a budget...I found a good primer called rustlok and cna actualy just use that. dont need to coat over it if necessary--i plan to do my bottom since its flat bottomed anyway with maybe a copper bronze--but would this cause the dissimilar metals to corrode|? i heard somewhere that this might happen with copper bronze??
     
  9. tugboat

    tugboat Previous Member

    yea sounds like people in your country are like us guys here trying to see if we can save a few bucks...my thinking was that if i thickened the epoxy a little it might just spread a bit better to the surface but im told that adding a pigment will leave an opaque look to it. and the thickener will whiten the black so ill just leave that one alone ..i will get a good primer and since no-one sees the bottom i may use a cheaper alternative..im going to spray paint the interior with black or grey enamel spray paint. the outside -all 550 sq ft of it will be done with a product from west marine -interlux- i think the salesman mentioned...some of the products that i need i cant get here--this is the reason im trying to find alternatives..for some lame reason the gov'ment wont allow certain paints into the country- for example i wanted this stuff called the "unepoxy' a "pettit" hard drying epoxy paint-it was cheap too-could do the boat for 200.00 - 300.00 but its not able to be imported...this is an issue and why i am seeing what else might work...
     
  10. tugboat

    tugboat Previous Member

    thanks- thats the thing--its a tugboat--so it doesnt have to have yacht quality paint--it just has to be strong and withstand the abuse--i thought--what if i used enamel spray paint primer and then balck paint--then a light coating of epoxy over that after it had dried thoroughly?
     
  11. tugboat

    tugboat Previous Member

    Paul what would 550 sq ft cost to do in this type of epoxy?
     

  12. tugboat

    tugboat Previous Member

    Paul i asked this on a previous post here- would copper bronze cause corrosion due to copper and steel being dissimilar? ie. electrolysis?
     
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