Two-part paint issues

Discussion in 'Fiberglass and Composite Boat Building' started by YoungGrumpy, Jul 15, 2013.

  1. YoungGrumpy
    Joined: May 2012
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    Location: New Jersey

    YoungGrumpy Junior Member

    The paint I am trying to use is URAGLOW™ 2-PART MARINE TOPSIDE URETHANE ENAMEL by Bluewater Marine. I've got it from a PO altogether with the hulls, and since the $$ is always matters, decided to give it a try. The paint label said "only for Professional application" and "spray application" I do not have the hardware nor the skills to use it, so I am struggling to roller paint it. (PO said he asked the manufacturer's rep, it could be rolled too).The plan was to roller two coats, wetsand it and put a finishing coat with roller/brush tip-off. Complete disaster. I was expecting a decent amount of orange peel, some runoffs...
    What I am getting is the paint is not covering properly and forming a lot of air bubbles. Tipping off is not helping. Plus, I am afraid it is not cured properly. Yesterday it was close to 95 F and humid, so I attributed it to the weather. This morning I wetsanded the boat, and when I went to wipe with the solvent, it was dissolving the paint to my surprise.
    This morning batch was close to normal temp (paint was stored overnight in the basement, air temp was around 75), still a lot of bubbly action.

    Any advice much appreciated!!!
     
  2. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    First...Professionals dont wipe down with solvent...they wash with water then let air dry. Solvent introduces contaminates , wipes contaminates into corners and kills employees.

    I dont know your paint brand. I use Awlgrip. Awlgrip mixed witrh brushing catyast then diluted with 30 percent "Brushing thinner" is perfect for roll and brush.

    Dont paint in direct sunlight. Dont paint a cold substrate. Tiny bubbles always appear from the roller. These bubbles are removed when you lightly brush the paint.

    Awlgrip Brushing Reducer extends the skin over time of the paint, allows it to flow out smooth and allows any micro bubbles to pop.

    I never have problems with bubbles in the finished product.

    Many times up to 35 percent brushing reducer is need. It depends on the complexity of the component and how much working time you need.....more working time means more thinner.
     
  3. YoungGrumpy
    Joined: May 2012
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    Location: New Jersey

    YoungGrumpy Junior Member

    Well,
    After wetsanding, I washed it with water, let it dry. Then just in case I wanted to be sure there is nothing else on the surface...
     
  4. RTM
    Joined: Jun 2013
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    Location: Central Florida

    RTM Junior Member

    Don't know about your brand of paint, I use AwlGrip which is also a two part poly. They make two different types of converters, one for spray painting, 1:1, and one for brushing 2:1. I have used both, It would be impossible to roll and tip when using the spray converter, it dries in a couple of minutes. Check with your supplier and see if that brand of paint also has a converter for rolling. Also the reducers might be different too. Also it is tougher to paint at 95 degrees, as drying time is quicker.

    rich
     
  5. YoungGrumpy
    Joined: May 2012
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    Location: New Jersey

    YoungGrumpy Junior Member

    Well,
    I just talked to the manufacturer's rep.
    He was not really helpful, no suggestions on the formulations, said what I've got should be fine for rolling, if it was not so hot!
    Basically, he said, do not try to paint in this weather, and do not rush it, even if the paintcoat looks dry, it is not cured, so I should not overcoat it the same day...
    I wonder if uncured paint when overcoated with more fresh paint would produce this bubbling?
     
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The LPU's can be touchy to environmental conditions and certainly rolling. The bubbling is caused by your roller. Foam works the best, especially if you tip off with each pass of the roller, by locking it with your finger as you drag it back.

    Some LPU's are just plain hard to apply without a HVLP setup. These paints tend to be a bit thin, right out of the can. This is normal. What would require two coats for good coverage, might need three with an LPU. Since you can apply these paints relatively quickly (HVLP), this isn't a problem, but if doing it by hand, expect the first coat to be translucent in some spots, especially if light over dark.

    Lastly, prep is the name of the game with a paint job and this includes the painting environment. If you can't apply in the recommended conditions, you can expect some issues.
     
  7. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    Just a quick note from a Perfection user (Interlux). I've found over the years that applying this LPU was as much art as science. If my memory serves me the manufacturer recommends 70's and reasonably low humidity for application. Good luck this summer in the Garden State if you're working outside. The instructions also recommended a 10% (down to none) of brushing/rolling thinner depending on temp/humidity. I found at cooler temps a "dash" of thinner helped me get a decent finish while at higher temps no thinner was needed at all, but never 10% I learned this as I went along as the LPU had a pretty long pot life. I painted a section and if it didn't look quite right I might add a little thinner and recoat. That's how I learned. Why not mix a few small batches of that LPU you have and do some trial and error before you paint your boat?
     
  8. swade
    Joined: Jun 2010
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    swade Senior Member

    Not the same product but I painted the other boat non skid areas with automotive urethane. I briefly considered rolling it but everything i read said it will have a ton of bubbles since it's intended for spraying. I happen to have supplied air, compressor,etc so i just did that.

    But if it's meant for spraying it may be very tough to roll. But one thing to consider is future touch ups...that's why on this next boat i'll be rolling something on more traditional and maybe not as tough. Just too much prep and work to spray come touchup time. I only did it because i was intending to get rid of the boat and had paint left over.

    I will say that urethane was tough though! I was dragging batteries across it without a scratch.
     
  9. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    You need the brushing thinner specified for the product to successfully roll and tip, in my experience.
     
  10. YoungGrumpy
    Joined: May 2012
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    Location: New Jersey

    YoungGrumpy Junior Member

    Thanks a lot for answering!
    Yep, this paint is tricky...
    I got up at 5 am this morning (after wetsanding yesterday in the dark), and went all over the surface with microfiber cloth. (No solvent, some condensation and water remaining from washing yesterday).
    Then mixed a batch of paint for topsides with a bit more of the reducer. The color the PO choose is "Flag Blue", really dark, so every imperfection is shiny and visible:eek:.
    First 30 min rolling with Hi-density foam and tipping with a decent brush (maybe not the best but still) were not that bad. 3 years ago I refinished my previous boat with Perfection Interlux. (I kinda assumed it is too late to buy all the hardware and learn a spray-painting at my age).
    This time however, the paint behaves quite differently. It is thin enough right from the can, and more reducer is not giving it more flow, just less coverage. And really the pot life is limited. At the last third of the second hull (this is a catamaran I am struggling with;)) was not that easy despite adding some more of the reducer. The roller was forming not just bubbles, more like a foam, that was drying right in front of my eyes.
    One side of one hull was actually a third coat, and it looks kinda passable (close by, you would ask Who did the painjob:p), but overall, there is a hope for me at the end, if the weather holds.
     
  11. michael pierzga
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    michael pierzga Senior Member

    Blue is always a difficult colour to apply. In a controled temp workshop its not so bad, but outside in sunlight or different substrate temps is a challenge.

    For tipping I use cheap throw away brushes and a foam roller.

    With white I can get away with two coats...blue takes three or four coat because of the amount of thinner required.

    Prep for your finish coat with very fine sandpaper.

    I find that wetsanding produces to many cut thrus in the paint film.

    I dry sand either by hand or with a random orbital designed for finish sanding.
     
  12. YoungGrumpy
    Joined: May 2012
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    YoungGrumpy Junior Member

    What would you consider very fine? 320 or 400?
    Thanks Michael, I almost lost my enthusiasm for this project!
    Yesterday I started with 220 and finished with 320, because some areas were really bad. But from now on I think no less than 320 should be ok.
     
  13. PAR
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    PAR Yacht Designer/Builder

    Careful with too fine a grit, as the paint needs "tooth" to hold onto the surface.

    One technique you can use for this paint is to reduce it significantly, then roll and tip, knowing you'll have lousy coverage. Apply two to three coats, within the recoat window, then wet sand the imperfections out and do it again. It's time consuming, but you can get enough film thickness for coverage and the wet sanding will fix the blemishes.

    If it's drying, before it has a chance to "self level" or flow out, it's way too hot to paint. Unless they have a special "tropical" reducer, you're going to have to wait for cooler weather or find some way to control the environment.

    Lastly, for a roll and tip technique to work, the tip off brush should be fairly dry and preferably foam. Naturally, you need to work the "wet edge", so if you can't maintain a wet edge, it's too hot. Hold the tip off brush nearly vertical and a very light tough is all you need. You're not trying to move paint, just knock down the roller stipple. If the brush loads up, wipe it off. I paint in hot conditions all the time and sometimes the best patch I can maintain a wet edge with is only a 12" square.

    In all honesty, it sounds like it's just way too hot. I run into this problem frequently in the summer, so I'll do temperature sensitive work at 3 in the morning, when it's cool enough for the paint or goo to lay down and flow out.
     
  14. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    400 grit for dark colours

    320 works with white

    When paint cures it shrinks. Coarse sanpaper marks will show thru the paint film.

    I typical sand with fine paper then take a scotchbrite pad...fine..and patrol around looking for shiney bits in corners or transition zones.

    Paint flows better over a sandpapered, scuffed, surface.

    One advantage of roll and tip is that since it takes two or three coats to cover you get practice with each coat.

    With spray you pull the trigger and hope for the best.

    With practice a roll and tip job can be applied to perfect yacht quality.
     

  15. YoungGrumpy
    Joined: May 2012
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    YoungGrumpy Junior Member

    Par,
    I could get up an hour or two earlier, but I do not think I will get a significant benefit, it was 75 this morning (so, 3-4 degrees, 30 more minutes to cure in a lower temp range), and 3 coats got me decent coverage with a very uneven surface. This paint is just not leveling out the way it supposed to. Plus, Manufacturer's rep said, I can not get more that one coat in a day, and my experience is, previous coat that looks pretty hard after 3 hours under the sun is dissolved by the new coat.
    So later today I will give it a sand all over again and tomorrow morning will start again.
     
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