So many opinions...what paint?

Discussion in 'Materials' started by daniel freixo, May 27, 2018.

  1. daniel freixo
    Joined: May 2018
    Posts: 4
    Likes: 1, Points: 3
    Location: Portugal

    daniel freixo New Member

    Greetings from Portugal! I have been restauring a classic GRP 14" "Whaler tipe", and after many yards of biaxial and resin, it is now time to paint.
    My question is: I repaired some areas of the outside bottom hull with epoxyed biaxial. The gelcoat is very thin and I will give it a good sanding and a barrier coat with epoxy.
    To a boat that is going to be trailered and will stay in water for 2 days straight, max, what tipe of paint should I use: polyurethane 2 part or epoxy? Don´t want to use antifouling because I don't see the need for it, but I want the strongest, most durable solution.
    Please help?... Thank you !
     
    Last edited: May 27, 2018
  2. Blueknarr
    Joined: Aug 2017
    Posts: 240
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    Location: Colorado

    Blueknarr Senior Member


    Welcome from California

    Easy answer: epoxy does not resist UV deterioration well enough for top coat painting. Its great adhesion makes for an awesome primer. 2-part polyurethane over epoxy primer should last a long time.

    Paul
     
  3. daniel freixo
    Joined: May 2018
    Posts: 4
    Likes: 1, Points: 3
    Location: Portugal

    daniel freixo New Member

    Thanks Paul, I will do just that. All the best
     
  4. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    Welcome to the forum Daniel.

    I'd agree with Blueknarr. The two part LPU paints are a bit expensive but they cure to a rock hard scratch resistant finish. I've always used Interlux Perfection but there are other similar products out there, Algrip is one of them. Do some research and practice your application on a scrap piece of plywood coated with epoxy. Follow the manufacturers instructions exactly and you will get nice results. Over the years I've found that people who have problems make two main mistakes. First they over thin the paint. For roller or brush application I start thinning at 5% if painting in cooler temperatures (say about 15 degrees C or so), if it's hot (say high 20's C or above) I usually use no thinner at all or maybe just a splash. The other mistake I've seen is over application. LPU's are thin. They are not like house paint. Use a chemical resistant foam roller, really short nap, 1/8" or so. When applying the finish coats of LPU remember the saying "less is more". I usually do three thin coats. One last thing, don't forget to use the correct primer. Good luck with your project and have fun out there!
     
  5. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    I am doing same project, 13' Whaler, only I just vacuumed a light skin over the old gelcoat. It is a bit non-traditional, I don't care.

    Wanted to avoid gelcoat.

    I used Awlgrip primer rolling and tipping and I absolutely hate it. I put a single coat of Awlgrip topcoat on it and it was a total failure due to the impossible to apply primer and the idiot operating the brush; sort of..

    The awlgrip topcoat was beautiful paint.

    The trouble with the primer is even with the brushing reducer at max; it has a 6 second or so wet edge only. It is a spray paint someone in marketing decided to call brushable. My inexperience shined through. Awlgrip primer is meant to be sprayed. It cost 480$. Then due to the problems with the primer drying so fast to tip; I used the max recommended reducer on the topcoat. The topcoat then took like 8 hours to dry and despite my sanding prep; the wet edge difficulties showed through.

    I sanded the topcoat off and am planning to redo the primer coat now with Epifanes epoxy primer which I am told is much easier to roll n tip.

    Anyhow, avoid the awlgrip primer, embrace the awlgrip topcoat and use minimum reducer in the topcoat unless you are gonna spray it all then I don't know. It is very nice paint if you get the primer prep right.

    My best advice.
     
  6. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    btw, you can refrigerate in a sealed container the awlgrip topcoat overnite for the next coat; despite it being 2 parts; it'll shelf cool for a day or so
     
  7. pescaloco
    Joined: Feb 2006
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    Location: so. california

    pescaloco Senior Member

    As has been recommended use an epoxy primer Awlgrip 545 roll on 3 or 4 coats (following recoat time window)
    sand all smooth with 320 grit
    Roll and Tip Awlgrip 2 part Polyurethane paint with a high quality natural bristle brush

    The Application of the primer is easy
    Use a good quality foam roller (hot dog sized)
    Roll on an even coat of primer and be mindfull of making ridges by pressing too hard on your final strokes. Let the primer tac off for a couple hours then roll your next coat, then repeat. 3 coats should do it if you have layed it down smooth.
     
  8. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    The 545 is the one I hate.
     
  9. daniel freixo
    Joined: May 2018
    Posts: 4
    Likes: 1, Points: 3
    Location: Portugal

    daniel freixo New Member

    Thanks to everyone, I do have some experience with LPU's, unfortunately Awlgrip in Portugal costs more than beluga caviar:(...I'm going with epifanes or hempel LPU, much harder than Interlux, even if it's a bit complicated getting a finish like Perfection. Thanks again and visit Portugal if you can, we got great waters, great sun, best seafood in the world and cold...very cold beer!:) You are all welcome here.
    Carpe Diem!
     
    fallguy likes this.
  10. Blueknarr
    Joined: Aug 2017
    Posts: 240
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    Location: Colorado

    Blueknarr Senior Member

    I bet Awlgrip doesn't taste as good as caviar. It is way over priced everywhere, guess someone has to pay the advertising in the glossy magazines. Look diligently and catalyzed urathanes with similar performance can be found for 1/5 the price of Allgripe.

    Down a cold one or even a vary cold few. Then post a pick of the finished project.

    Paul
     

  11. daniel freixo
    Joined: May 2018
    Posts: 4
    Likes: 1, Points: 3
    Location: Portugal

    daniel freixo New Member

    My point of view also ;)...
    I will post some pictures, It has been a long project, bringing a small 90's fiber boat to the 21st century, with a modular deck system, to fish as open bow in the sea and platform bass machine in fresh water.
    There are crazy guys...then there is me:):). Cheers!
     
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