CPES- (clear penetrating epoxy sealant)- uses, and how to make your own…

Discussion in 'Materials' started by hansp77, Jun 6, 2006.

  1. bntii
    Joined: Jun 2006
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    bntii Senior Member

    PAR- you do much peel/re-lam blister repairs?

    I've done a good many and use epoxy exclusively but just had yet another emphatic:
    "we stopped using epoxy 20 years ago for blister repairs for good reason- epoxy just doesn't stick to old polyester"

    Same guy gave some complex explanation of how entrapped styrene in old poly boats chemically bonds to poly used so makes this a better choice than using epoxy resin for all repairs:

    "Polyester boats should be repaired with polyester, only use epoxy on epoxy hulls"

    Both these statement don't fly with my understanding and experience but are strongly held by the guy.

    "Can't teach a old dog" or?

  2. TeddyDiver
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    TeddyDiver Gollywobbler

    Helps a lot if water soaking blister are all cleared away and the laminate had a good time dried out, but if someone wont do the job right from the beginning.. :rolleyes:
  3. michael pierzga
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    michael pierzga Senior Member

    If you are in Maryland and need technical advice for an osmisis blister repair contact Craig Bumgarner.


    " Epoxies, if done well, offer much higher resistance to moisture but are less compatible with the original hull resin and are very costly and hard to work.
    Vinylester resins offer a high degree of durability at a cost in between epoxies and polyesters and though harder than polyester to work, experience permits us to use vinylester for all our layup work these days. "
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I don't see as much blister repair as I use to, but epoxy is the usual choice. Any argument that epoxy doesn't stick to polyester flies in the face of all testing independent and in house. When I hear things like this I immediately discount it for self serving BS. He probably just doesn't want to learn epoxy and is completely comfortable with poly, which is a common thing among laminators and repair personal. Just look at some of the biases you've seen here and multiply by a few decades of familiarity.

    Michael, don't misinterpret the results of that test. Incompatible chemistry is a given (and necessary), but the physical properties of one, on another are well documented and vinylester doesn't come close, though compared to polyester, it's quite good.

    This debate is long over folks, the jury has come in on all long term studies and though some advances have been made with the poly's, they pale in comparison to epoxy in most every regard. The cost difference is negligible, once all things are consider (vinylester/epoxy comparison) and the physical properties "package" significant.

  5. bntii
    Joined: Jun 2006
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    bntii Senior Member

    Thanks guys- that is what I was thinking.
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