Painting over flowcoated Gelcoat question

Discussion in 'Materials' started by pescaloco, Jun 10, 2017.

  1. pescaloco
    Joined: Feb 2006
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    pescaloco Senior Member

    I would like to know what is the recommended solvent to dewax a flowcoated Gelcoat surface to prepare for a 2 part LP paint, I plan to do some light sanding but there is a lot of texture in the Gelcoat and areas where the weave of the cloth shows through.
    So it is not realistic to think every bit of the surface will be sanded.

    I plan to paint over the Gelcoat without the use of epoxy Primer
    The cosmetics of the paint don't need to be perfect I am just trying to improve the appearance of my below deck areas.
    Can I reasonably expect the paint to adhere long term and not to fish eye from wax that may remain on the substrate.

    Thank you
     
  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    Did you just apply this flowcoat, if so you need to remove all the wax and abrade the surface. As you know, with the texture you can't just sand it, so a stiff wire brush works as well as anything. If this is an old surface you just need to clean it well and use a little less effort with the wire brush, an old surface will have been beat up pretty well already, so it won't need as much abrading.
     
  3. pescaloco
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    pescaloco Senior Member

    Thanks for the reply

    It is fresh
    I was afraid of that
    What would you recommend to remove the wax ? I would use Acetone and a stiff scotchbrite pad but not sure what is best
     
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  4. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    It sounds like old flowcoat, but inside, out of the weather. Using a de-waxing solvent in a confined space does not seem like a good thing for your health. My advice would paint a small part out of direct sight, as it is, allow it to dry for a couple of weeks, then apply the "X" cut test with some cello-tape. If it does not lift, the adhesion will be good enough. Painting gloss paint over flowcoat will show up the unevenness markedly, even flowcoat without speckle-paint can look less than workman-like, even with the matt finsh.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    So it is new ? I would not sand, initially anyway, just experiment with various de-waxing methods, starting with the least noxious, if it gets squeaky, it is clean enough !
     
  6. terrnz
    Joined: Mar 2014
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    terrnz Junior Member

    Acetone, scotchbrite then 80 grit and a sander. Tip rub vaseline into yourself and don't take a hot shower after but a hot bath. if you are using a 2 pot epoxy paint or long chain polyurethane please use an undercoat. What level of finish do you aim at, gloss , satin, matt? Just remember the topcoat is only as good ar what is underneath!
     
  7. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    Acetone typically evaporates too quickly, you need something that will stick around a bit longer so it can be cleaned up and removed from the surface, not just spread around. Floor wax stripper may work, but I've never used it, auto parts stores carry wax and grease remover for paint prep, then clean with soap and water prior to using the wire brush.
     
  8. terrnz
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    terrnz Junior Member

    last time I did it I think I used epoxy thinners.
     
  9. pescaloco
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    pescaloco Senior Member

    Thanks for the replies
     

  10. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    The only paint I use on my boat (aside from a bottom paint) is Interlux Perfection. Over the years I've talked with many people who seem amazed at the results. They say things like "I've heard it runs" or "I had bad luck with it" or "It came out bad for me". I've learned one thing. Follow the manufacturers instructions to the letter and you'll get a good result. Interlux is very specific about painting over gelcoated surfaces. They recommend a product called 202 Fiberglass Solvent Wash. Use it. It's not that expensive. Since you're working in an enclosed space a couple of good sized fans will help with the fumes. After the surface is cleaned up use an Epoxy Primer, Interlux Epoxy Prime Coat is recommended. Again it's not expensive (about $90 for a gallon) and will give you a stable base for the LPU to adhere to. There is a reason that an appropriate primer is necessary. Do the job once and do it right. I've never had a failure with these paints over many years of service but I follow the manufacturers instructions to the letter.
     
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