Refinishing Gelcoat

Discussion in 'Fiberglass and Composite Boat Building' started by Charlie A Bess, Apr 12, 2019.

  1. Charlie A Bess
    Joined: Apr 2019
    Posts: 2
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    Location: Miami,Fl

    Charlie A Bess New Member

    Hi guys, I am refinishing some gelcoat on my boat. Any suggestions on what kind of dye I should use when sanding with the DA?
     
  2. Blueknarr
    Joined: Aug 2017
    Posts: 706
    Likes: 115, Points: 43
    Location: Colorado

    Blueknarr Senior Member

    Welcome to the forum

    No dye should be used when sanding gelcoat with a DA.

    Exactly what is wrong with the gelcoat that it needs refinishing?
    Are you repairing chipped, scraped or cracked gelcoat?
    Or, simply restoring lost gloss?

    Pictures say a million words.
     
  3. Charlie A Bess
    Joined: Apr 2019
    Posts: 2
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    Location: Miami,Fl

    Charlie A Bess New Member

    I think there is a misunderstanding....Let me re-phrase. I am re-fairing the bottom of a one design dinghy. I have gone through the whole process multiple times so I know how it works. To keep track of what has been sanded using a DA, many people use an ink diluted in acetone. I am asking for suggestions on the ink used to track sections on sanding.
     
  4. Blueknarr
    Joined: Aug 2017
    Posts: 706
    Likes: 115, Points: 43
    Location: Colorado

    Blueknarr Senior Member

    Now I get the picture.

    Try using cheap spray paint. Quickly mist a coat of contrasting color.

    DSC02392.JPG
    Obviously not a boat, but an example of rattle can mist coat. If you use more than one can it is too thick.

    I highly recumend switching to longboards for fairing.
     
  5. redreuben
    Joined: Jan 2009
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    Location: Beaconsfield Western Australia

    redreuben redreuben

    India ink works fine
     
  6. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    What is a DA sander ? Dead ahead ? Dust accumulating ? Dual action ?
     
  7. redreuben
    Joined: Jan 2009
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    Location: Beaconsfield Western Australia

    redreuben redreuben

    India ink in acetone
     
  8. Blueknarr
    Joined: Aug 2017
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    Location: Colorado

    Blueknarr Senior Member

    Duel action. Has the capability to be both a spin sander and random orbital sander. IMO it doesn't do either very well. The ones I have used lack the torque of a dedicated spin sander and is too tall to have the finesse of a random orbital palm sander. Certainly not my first choice of sanding gear for fairing a dinghy hull.
     
  9. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    As mentioned, a cheap rattle can primer works. That or dye, primer may be easier to find.
     
  10. redreuben
    Joined: Jan 2009
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    Location: Beaconsfield Western Australia

    redreuben redreuben

    Sand with block or board. Electric sanders just make mistakes faster.
     
  11. KD8NPB
    Joined: Mar 2018
    Posts: 69
    Likes: 11, Points: 8
    Location: South Carolina

    KD8NPB Junior Member

    Blue machinist layout dye mixed in acetone is popular. Prussian blue is kinda toxic though.

    3M Dry Guide is my preference.
     
  12. Zippydoodah
    Joined: Jun 2019
    Posts: 8
    Likes: 0, Points: 1
    Location: Christopher, IL

    Zippydoodah Junior Member

    Yes there is a thing called ink you can use. Its comes in dark purple. I dont remeber the name brand. We diluted ours with acetone and because it was so dark you want to really light purple when we did ours easy to work with less Sandy and it'll it'll sand off I easily on the areas you don't need it and it'll stay in the cracks we can rout them out and fix them if you have any. Or there's a thing called charcoal dust and now you can put it on there and it'll stay where you got to have it
     
  13. Steve Clark
    Joined: Jul 2004
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    Location: Narragansett Bay RI

    Steve Clark Charged Particle

    Dyekem or equivalent machinist dye found in your local machinist supply shop. Assuming you still have one. If not order on line. The spray paint trace coat works for fairing, but doesn’t get into the scratches left by coarser grit sandpaper, so won’t provide the detail.
    If you are trying to be super fair, you shouldn’t use a DA, but should stick to sanding boards. Even in expert hands, the DA induces some undulations.
    SHC
     

  14. djamson
    Joined: Jun 2019
    Posts: 12
    Likes: 0, Points: 1
    Location: Fl

    djamson Junior Member

    Another vote for 3M Dry Guide. Easy to apply and offers great coverage.
     
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