Epoxy & paint

Discussion in 'Boatbuilding' started by goodwilltoall, Jul 19, 2012.

  1. goodwilltoall
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    goodwilltoall Senior Member

    Greetings,

    Did some tests with 2-1 epoxy mixed with silica sand along with variying porportions of acrylic paint. The exterior paint was Sherwin Williams best exterior latex called "Duration".

    The purpose was to basically see if it would sufficiently pigment the epoxy, which it did and the finish with the sand seemed it would make excellent grip on deck.

    The next day the epoxy was very flexible but still adhered to the wood very well and only split at the wood. The other samples gradually hardened over the next day so it wasnt overtly soft. You could slightly scratch it pushing very hard with nails. The thing that surprised me most aboout the paint was it thixothropic effect, with about 30% it made the epoxy like vaseline consistency, it was very tacky and would stretch but would not run whatsoever, excellent gap filling.

    Should work as a work boat paint system if the paint in the epoxy protects it from UV? Will this work? Forgive me if this is a repost, did a search without success.
     
  2. mastcolin
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    mastcolin Senior Member

    what epoxy did you use? "2-1"? this is a waterbased solution epoxy as opposed to solvent-free?

    If you added latex paint to solventfree spoxy you have just made yourself a mess with all the benefits of neither.

    The water in the latex will mess with the curing agent. It won't come out also. You will have a less than fully crosslinked film that is cheesy and will probably blister in time. And fall off.

    The resins in the latex paint are probably not even soluble in the epoxy so you get a strange mix. Without getting too technical, you get 2 phases. Imagine oil and water. Sometimes this can be beneficial. for what you are doing, not.

    It will add zero benefit to UV protection. Even if you add pure pigment white to epoxy it will break down at surface.

    If you want to pigment epoxy (solvent free or waterbased) you would be better of getting hold of pigment pastes which are "solvent-free". I use this loosely. They have extender solvents which will stay in film ie very high boiling points.

    Far better would be to coat with epoxy. Sprinkle on sand when tacky. Allow to dry, brush off loose sand. Paint. Or buy something designed to do the job.
     
  3. PAR
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    PAR Yacht Designer/Builder

    Sand is about the worst material to use for a textured surface. It looks and wears well, but is impossible to remove or repair. There are all sorts of good texture materials you can get, with polyurethane granules being right at the top. All paint stores sell it.

    As pointed out acrylic paints will usually screw with the hardener, which you've found out as it should have been rock, not sort of hard, the next day.

    There will be some UV protection, but so what, the goo hasn't kicked, peel strength and surface protect are quite questionable. Colin is correct the surface will still break down, exposing new epoxy to UV, so what's the point.

    The pigments in acrylics will likely stay in suspension in epoxy, but all the other stuff will prevent epoxy from becoming cured epoxy. You can get liquid or powder pigments that are compatible with epoxy. In most cases they are mixed with the resin only, then the hardener is added.

    Rather the sprinkling texture granules on tacky goo, sprinkle it on when it's very fresh. This will insure the best contact with the "adhesive" and the granules will stay stuck longer too. Sugar and salt make good texture if you want to be cheap about it. In fact, if used on a surface that will eventually be varnished, you can wash out the sugar or salt when the goo cures, then over coat with varnish, for a clear coated textured surface.
     
  4. goodwilltoall
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    goodwilltoall Senior Member

    Greetings,

    From previous samples the epoxy eventually does harden and bonds well but, different characteristics are exhibited.

    Applied epoxy/acrylic paint mix to a horizontal surface yesterday afternoon that will recieve alot of wear. This morning felt the surface and it was still slightly tacky although temperature was a little cool last night. From experience more time needed.

    Started out with the two mixed together and stopped because as mentioned, something about the paint really binds it up into a thick paste. So just spread out new epoxy alone and applied the paint on top 2hrs later while it was still tacky, did not use sand as grip was'nt necessary.

    Will give it a second try on something else by mixing epoxy/sand and then applying paint while still tacky, will have to see if the paint rolled on diminishes the grip to much, if so bigger grain size should fix it. Did one sample with all three mixed and it came out excellent but it was applied with a popsicle stick and the mix self leveled to a beautiful surface, it was mildly translucent, no good if this will quickly breakdown.

    BTW, who has best pricing on about 10-20lbs cabosil, looked around and found Noahs in Toronto as best yet.
     
  5. goodwilltoall
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    goodwilltoall Senior Member

    Reread you post Par, this would be a permament application, so shouldnt need to do repairs.

    Read many good reports on todays latex paints and feel that on a wood/epoxy boat its ideal so hence the reason for incorporating it rather than others, along with cost benefits.

    Reason for going this route is because of adhesion issues and think the paint applied on tacky epoxy is best solution even if the surface appearance would be a grade C or D as long as its durable thats acceptable.

    Painted a fiberglass truck body with "Duration" high gloss over a previous *****l finish; sanded, washed and rolled on, about 15,000 miles later the gloss is gone (was never really there in first place) the paint is still holding tenaciously.
     
  6. goodwilltoall
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    goodwilltoall Senior Member

    Mastcolin, the epoxy is 100% solids, 828 and amidoamine CA, dont think its water based but guess it is once the paint is added. Will see how this holds up, will have it in partial sun along with other samples to follow shortly which will also have UV exposure, one of them has to work. Probably next year will apply to boat unless things go really well and try later this year.


    Par, does Sherwin Williams have polyurethane granules?
     
  7. pauloman
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    pauloman Epoxy Vendor

    If you saw acrylic latex paint under a microscope it would look like a bunch of ball bearing that gradually fuse together over a few days of drying. That will not happen when mixed with epoxy.

    For non skid PAR is correct to say no sand on a boat. Common alternatives are ground walnut shell (comes in lots of grits) - it is dense wood and stay suspended in most coatings so you can mix in or broadcast on top ( textures will be different). Ground rubber grit also works well on boat decks. You put the grit into the epoxy and then you can control how rough it is with the number of topcoats of paint (also even out the grit pattern/texture with some 'repair' grit in one of the top coats of paint.

    water based epoxies are used only for floors (maybe as a primer) because they need lots of 'air' for the water (and solvents) to evaporate away. All (that I know of) water based epoxies also contain a good bit of traditional solvents. I cannot sell my waterbased epoxies in part of California.

    paul
    progressive epoxy polymers inc.
     
  8. groper
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    groper Senior Member

    water + uncured epoxy = fail.

    acrylic paint = water

    epoxy + acrylic paint = told you so...
     
  9. PAR
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    PAR Yacht Designer/Builder

    I love these home brews without engineering common sense. It's one thing to mix things knowing or at least having an idea what the reactions might be. It's another entirely to do something with hope as the guiding force behind it. I discovered this very early in life, when I found the formula for mercury fulminate and decided to mix up a batch as a 14 year old. The reaction was, well; a bit more than I expected lets say.
     

  10. goodwilltoall
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    goodwilltoall Senior Member

    Epoxy paint system described has hardened considerably and will get plenty of abrasive use conditions along with UV exposure so time will tell, only thing that could have been better is the latex paints are lacking in the high gloss area and it gets dirty quickly.

    Also had a corner area that will also recieve extended abuse on a daily basis. It is black colored but didnt have black paint so mixed quick setting polyamide with a bronze polyurethane caulk called "dymonic", it looks good, feels, and think it is good but, again time will tell. These were things for appearance sake that needed to be repaired and epoxy made it quick. But also experimenting for knowledge.

    Still need to know exactly why sand will not work for grip deck, like the other ideas of salt, polyurethane, and rubber. Did have to sand some epoxy with silica sand just today and it was a little more difficult than usual but with electric tools rather insignificant overall.
     
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