New to site and need assistance with Gelcoat

Discussion in 'Fiberglass and Composite Boat Building' started by Judd Berman, May 4, 2018.

  1. Judd Berman
    Joined: May 2018
    Posts: 1
    Likes: 0, Points: 1
    Location: Massachusetts

    Judd Berman New Member

    Hello,
    I'm new to this site and need some advice/help. I recently had to have some repairs done on a livewell for my boat. The fiberglass work was completed and I had someone spray it with gelcoat. The guy who sprayed it isn't used to spraying gelcoat and the finish is far from smooth. It almost looks like the skin of a cantaloupe. Can this be sanded flat with 200 grit and shined up? Any advice would be appreciated?
     
  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    That finish is normal for sprayed gel coat.

    Yes, it can be sanded and polished to look much better, you want to start with as fine a grit as possible, otherwise you will spend much more time than needed sanding out the scratches from an aggressive grit.

    You'll need to sand with a series of grits up to around 800, and maybe finer depending on a few variables, then buff and polish. Sanding with just 200 would leave you a nasty looking scratched and dull finish. Try 400 first, if that's too slow try 320, hand sanding will be very slow, so try a DA if you have one.
     
  3. ziper1221
    Joined: May 2018
    Posts: 28
    Likes: 5, Points: 3
    Location: florida

    ziper1221 Junior Member

    You need to progressively sand it if you want it to look good. Depending on how orange peeled it is start with ~200 and work progressively to 2000 grit. After that hit it with a polishing compound. Alternate sanding in 90 degrees. That way you know when you can move to the next grit when you can no longer see the scratches from the last grit.
     
  4. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    2000 grit on gel coat is a waste of time and money, rarely do you need to go past 1000, and you don't need to use 1000 often. Again, there are some variables involved with certain gel coats.
     
  5. ziper1221
    Joined: May 2018
    Posts: 28
    Likes: 5, Points: 3
    Location: florida

    ziper1221 Junior Member

    Is the difference in the buffing compound then? Because I saw a noticeable difference when working between 1000 to 2000.

    Edit: I guess it depends on what kind of finish you are looking for too, probably a little laxer with a livewell
     
  6. ondarvr
    Joined: Dec 2005
    Posts: 2,468
    Likes: 292, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Sand papers and buffing compounds can vary a great deal, so can the gel coat you're working with.

    Hand sanding leaves much deeper scratches than a DA will, so you may need to go finer.

    Starting with a coarse cutting compound and then going to finer polishing compounds will yield a much better gloss. Using a wool pad to cut and a foam pad for the finish works well.

    I can normally sand with 800 on a DA, then polish and get an excellent finish, and on some gel coats you can get there from 600 grit. (I'm very lazy and hate hand sanding, so 95% of the time I'm not hand sanding)

    Tooling gel coats tend to be harder and need finer grits and more buffing.
     

  7. Blueknarr
    Joined: Aug 2017
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    Location: Colorado

    Blueknarr Senior Member

    Ondarvr is who I go to if I have gelcoat questions. I spray gelcoat weekly.

    Wet 600 grit by hand quickly removes orange peel. 800 is easily buffed.

    Black gelcoat gets 2500 to remove any swirls created by buffing compound, then I use a polishing compound specialty formulated for black
     
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