Non-smooth varnish & epoxy

Discussion in 'Boatbuilding' started by trunge44, Jan 29, 2016.

  1. trunge44
    Joined: Jan 2016
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    Location: NY

    trunge44 New Member

    Hi, I'm a novice builder and realized I probably messed up my finish. I'm building a wooden sailrig to attach to a kayak. It is fiberglassed/sealed with epoxy. I was a bit hesitant when I began to varnish since the amas/outriggers do not have even epoxy layers (were applied with rollers). I sanded them with 320 grit sandpaper which did not eliminate the wavy appearance from the uneven layers before I began to varnish.

    I read something that made me believe enough varnish layers would correct/hide the uneven epoxy, however after 4 varnish layers (light wet sanding with 400 grit in between coats) I still see the wavyness. The varnish I'm using suggested 4 coats at minimum.

    If I continue to add varnish, will it eventually fill in the wavyness/uneven layers? Or will the epoxy wavyness show through regardless of the varnish smoothness? If the latter, would the only fix be to sand off all varnish and to fix the epoxy layer (I would probably just accept the non-perfect finish)?

    I just applied a 5th layer tonight. My next thought is to more aggressively wet sand followed with 2 more layers.

    I would appreciate any advice. Thank you!
     
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    If you paint over 40 grit sand paper, what do you think will be the result and how many coats of paint do you think it'll take to make it look better? This is what has happened, you've painted a clear coating over a rough surface, so yeah you can apply more clear, but you're just wasting material at this point and the rough surface is still visible.

    Start over, by sanding all the varnish away, in the process knocking down the high spots in the epoxy. Once you're down to the epoxy, knock it smooth with a long board if necessary and you might need more epoxy, to seal things up where you've ground down to raw wood again. As a rule, rollers will apply a nice uniform film thickness, but they also leave lots of bubbles and stipple, so you need to address these before the goo hardens.

    In a nutshell, you apply clear coats (varnish, urethane, etc.) over fair and smooth surfaces, if you want it to look right. If the surface is rough, it'll look like what it is - a clear coating over a rough surface.

    Log onto westsystem.com and systemthree.com and download their free user's guides and epoxy book. This will cover the basics. My site has some information too.
     
  3. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    +1 for Par's explanation.

    A rough epoxy base will always look bad.
    Epoxy is always rough when applied, it doesn't self level - it has to be sanded level.

    Sorry
     
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    I agree with you both. No amount of varnish will cover a rough epoxy surface. It will always show under it.
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Epoxy does self level, once you understand how to apply it, in the conditions you're working in. Brushes and rollers aren't the best way to put down finish coats, but squeegees and plastic applicators are, much more forgiving, in this regard. Temperature for the hardener/resin combination is very important, both on the substrate and the resin.

    It's just like any other coating, you build film thickness and smoothness with each and subsequent coats, until you're at the desired point in both (smoothness and film thickness).
     
  6. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Epoxy doesn't self level like paint or varnish.

    Is that OK?

    I completely agree, you can do better than a novice if you have the right technique and experience. I don't think the OP has either.
     

  7. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Agreed, epoxy doesn't self level like paints or varnish, but with technique, you can get it very close.
     
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