How to Prepare for Complete Gelcoat?

Discussion in 'Boatbuilding' started by michael.brito, Sep 21, 2010.

  1. michael.brito
    Joined: Sep 2010
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    Location: Bristol, RI

    michael.brito New Member

    Hello Everyone. I own a 1985 Hobie 18. I would like to completely refinish the boat in white gelcoat. It is currently a very sun-faded, chipped and scratched orange with a brown pinstripe. There is no fiberglass damage to worry about. I'd like to prepare the boat as much as I can to be gelcoated by a local boat shop. The goal is to save money by performing the prep work myself.

    From what I have read I figure I need to remove the hardware, remove the pinstripe, sand the old gel down and feather the cracks. Is this right?

    What is the best way to remove the pinstripe? Heat gun? Acetone and a knife?

    How much of the original gelcoat should I remove? Should I sand right down to the fiberglass? Should I wipe the boat down with acetone after sanding?

    Am I missing anything?:confused:
  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    A heat gun and a plastic ice scraper work well to remove the pin stripes.

    You need to fix and cracks, not just feather them, this means you need to grind them out, they may only be in the gel coat, but they may go into the laminate. If they do you need to grind them out and re-glass them.

    Don't sand the gel coat off, just use 80 grit sand paper and make sure the entire surface has been sanded, no shiny spots can be left.

    Leave the cleaning to the guy doing the gel coat job, it needs to be done right before its sprayed.

    Have you thought about painting instead?
  3. Landlubber
    Joined: Jun 2007
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    Location: Brisbane

    Landlubber Senior Member

    ...misssing the whole plot mate, the boat needs to be painted now, not gelcoated. Sand down and spray with epoxy high build primer, then followed with two pack linear polyurethane, she will be better than new.
  4. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    I fully agree with Landlubber.

    The 2-pack polyurethane is often sold as "Gel Gloss" or "Top Coat", hence the confusion.
  5. michael.brito
    Joined: Sep 2010
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    Location: Bristol, RI

    michael.brito New Member

    You really think paint will do the job? My concerns are that:

    • This is a beach cat, won't beaching scrape the paint off?
    • There are deep scratches and large chips in the gel that leave the fiberglass exposed, shouldn't there be gel there to protect the fiberglass?
    • Because of years of beaching, the gel coat has thinned under the hulls to the point where I can begin to see fiberglas through the very thin layer of gel left. Paint will not protect the boat as well as gel right?

    What path should I go down to get this boat looking new and protect the fiberglass hull structure from damage due to frequent trailering and beaching?

  6. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    My boat was Skandinavian built with Navy-gray gel coat. To avoid being regarded as a Navy vessel in the tumultuous Balkan region, I sanded it and painted it white with "Veneziani Gel Gloss". That was 12 years ago and except on a few spots where I scratched it accidentally with sharp metal objects, it is still looking very good.

    Where the glass is visible in deep scratches you must repair the hull with a filler first. In fact, polyurethane and epoxy protect the fiberglass much better than any gel coat.
  7. psarvich
    Joined: Sep 2010
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    Location: sfla

    psarvich New Member

    I tried to reply to your post yesterday,but somehow my computer went haywire.Do it yourself!If you are prepping the boat for someone else to do the work,you are doing 80% of the entire job.E-mail me and I'll tell you how to gelcoat the hobie cat.I am gelcoating a 40 foot Marine Trader trawler and it looks great.Why pay someone to do the work,when you can do it yourself.You'll have more pride in your boat if you do the work.My e-mail is
  8. pauloman
    Joined: Jun 2010
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    Location: New Hampshire

    pauloman Epoxy Vendor

    google LPU - linear polyurethanes for more info on 2 part polys.. they commonly go over a solvent thinned epoxy primer. cost is $100 per gallon to about $500 per gallon -one of those big marine rip-off products. Cheaper might be an enamel with a clear lpu topcoat (sort of alike auto clearcoat)

  9. keysdisease
    Joined: Mar 2006
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    Location: South Florida USA

    keysdisease Senior Member

    Paint. Forget gelcoat. Find a local boatyard (you're in RI should be easy) and talk to the paint foreman. See if you can make a deal for the next time they spray a boat for them to shoot your little hulls at the same time. They will be using Awlgrip or Imron or Sterling all very good products.

    At the same time ask about prep. They will recommend the primer (awlgrip 545) and tell you what grit to sand to. You can actually make a surface too smooth for paint to get a good grip so don't get carried away.

    These guys mix up a bunch of this stuff, use it all the time, and get great results. You would never know just how good a good paint job looks unless you see two hulls next to each other, one gelcoat and one paint. Night and Day. They have to use the paint they mixed or put in the frig and hope they can use it in a day or so because it will go off after being catalized. Give them a chance to shoot a little project like a couple of lil hobie hulls with "leftovers" and you might all be a little happier.

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