non waxed poly resin and sanding

Discussion in 'Boat Yard Basics' started by david_kohler, Jan 13, 2014.

  1. david_kohler

    david_kohler I Love microskiff.com!

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    I am good when working with epoxy, but I have a friend that is wanting to do some work with polyester resin.  I've read that most use un-waxed polyester resin and that it stays tacky in order for adhesion on the next coat of poly, paint or gel.  How does this effect sanding in-between coats? I would think a sticky resin would clog up sand paper pretty quick.
     
  2. PG350

    PG350 I Love microskiff.com!

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    You need to seal it off from air for it fo fully cure.
     

  3. PG350

    PG350 I Love microskiff.com!

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    You need to seal it off from air for it fo fully cure.
     
  4. david_kohler

    david_kohler I Love microskiff.com!

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    Thanks, but how do sand in-between coats if the resin stays tacky or is it really not that tacky enough to clog the grit of say 80 grit sandpaper?
     
  5. cutrunner

    cutrunner Cert. Yamaha technician

    The whole point of the no wax is so you don't have to sand inbetween coats if you do your next layer within the accepted window of time since the last layer.
     
  6. david_kohler

    david_kohler I Love microskiff.com!

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    If I'm filling a hole and using 3 layers of cloth to build it back up to match the existing and my patch it a little bigger than the whole, I'm used to sanding the patch around the edges to make it match. Will this gum up the paper? It's a painted hull and very thin at that. It would be nearly impossible to get the last patch to lay smooth and at the exact height of the surrounding area. Sorry for the confusion and I really do appreciate the help.
     
  7. PG350

    PG350 I Love microskiff.com!

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    I have been told not to sand it cause it will gum up the paper. That is why I bought epoxy. Can someone with more experience chime in please.
     
  8. david_kohler

    david_kohler I Love microskiff.com!

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    I've seen were some have said to add wax to the final coat of poly.

    I might tell my friend the only way I'm will to help is with epoxy. I redid my boat with west systems too. I built some parts with poly but did a final coat of epoxy because the rest of my boat was done with it.
     
  9. DuckNut

    DuckNut Brandon, FL

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    Shallow, you will be fine. It might clog some but it won't be like sanding wet caulking.

    Although epoxy is a better choice, many boats are repaired using esters.

    If the hull is really thin then epoxy might be a poor choice as it flexes differently than ester.
     
  10. david_kohler

    david_kohler I Love microskiff.com!

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    Thanks Ducknut, that's the answer I was hoping for. I just keep picturing sanding wet glue.
     
  11. Brett

    Brett > PRO STAFF <

    You can sand laminating polyester resin.
    In fact it's often necessary on many layups, where an air bubble
    forms between layers due to uneven tension in different sections
    of the woven roving. Can't sand the laminating resin with fine grit.
    On the few hulls I've had to re-stringer, a 36 grit disc
    on an electric grinder removed the problem and feathered the edges.
     
  12. NoeSmyrnaBch

    NoeSmyrnaBch Well-Known Member

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    i didn't add any wax and I didn't have any real issues with my build. As mentioned, sanding by hand isn't really an option unless you hate your arms...and yes you will go through some paper but its not THAT bad. Like DuckNut said...its not wet...just a little tacky from my experience. Not sure what he's using but I was using the FGCI Boatyard resin.
     
  13. DuckNut

    DuckNut Brandon, FL

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    FGCI as well, all levels of their resins. I do not use their epoxy.
     
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