Epoxy versus vinyl ester

Discussion in 'Materials' started by Roly, Sep 25, 2010.

  1. Roly
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    Roly Senior Member

    If epoxy is significantly more temperature sensitive than VE in terms of permeability and the range the resins were tested at (to speed the process) was way outside normal immersion temperatures, then surely this would skew the results?
     
  2. Landlubber
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    Landlubber Senior Member

    ...you think like i did mate, but I understand the "aging " process, the high temp forces results, but are they practical results when the mix is never going to face such real life temps, no, but the fact remains, it IS a good way to see "time" results.....
     
  3. Roly
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    Roly Senior Member

    No.
    I can only rationalize it as valid if the two resins behave the same at higher temperatures.
    Otherwise another variable is being added other than "equal time immersed", that being their differing permeabilities with temperature. This, in effect, makes immersion times unequal.

    Their permeability and subsequent strengths should have been measured at service temperature, not at double service temp.
     
  4. apex1

    apex1 Guest

    We are coming closer!

    Bravo.
     
  5. fg1inc

    fg1inc Guest

    A word of advise to rwatson....salesmen are not and usually have never been fiberglass techs. In my business there have been more problems caused by salesmen than any other single source. They haven't spent time on the shop floor and they do not understand the chemistry involved. Most manufacturers have excellent tech lines manned by knowlegable techs. That's where you'll find real answers.
     
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  6. PAR
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    PAR Yacht Designer/Builder

    Absolutely correct Fg1inc. You have to talk to the chemists or technical advisers if you want answers to real questions. If you're well versed in the chemistry involved the the chemist will do. If you need to be hand held and have "plane" language used, then the technical advisers at the ticket.

    Speaking of which, I apparently set off a bomb over at West System and the Iranian PDF is now revolving through several of the technical staff. They'll get back to me again eventually.
     
  7. apex1

    apex1 Guest

    You can be a nasty guy Paul, no doubt.:cool:
     
  8. rxcomposite
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    rxcomposite Senior Member

    In real life? well, it is predicted for 25 years before a laminate will lose 30% of their original strength value. (Springer-Environmental Effects on Composites Material)

    Note that there were other studies made on degradation of composite materials due to water absorption.

    Considering that a properly designed laminate (as with most class standards) uses only 33% of the ultimate strength of the material. That gives us a safety factor of 3. If you lose 30% of the strength in 25 years, that will leave you with 70% of the strength available, or a safety factor of around 2. That is after 25 years.
     
  9. Roly
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    Roly Senior Member

    Ir#*ian and B#*B?
    Expect your cell ph's to be monitored today boys!
    Better skip seeing the mistress.
     
  10. srimes
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    srimes Senior Member

    lol. Good thing nobody said anything about Al-Qaeda, Bin Laden, or Jihad!
     
  11. PAR
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    PAR Yacht Designer/Builder

    I make it a point to mention those three phrases each time I'm on the phone, just to keep the boys in the dark blue Crown Vic in front of the house. It's cut down crime in the neighborhood by a huge factor.
     
  12. rwatson
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    rwatson Senior Member

    Well, thats why I persist with questions. But ever try talking to the 'guys that know'. They are so busy educating salesmen, they never return calls or put anything in writing.

    Rxcomposite - thanks for the feedback on the 'real life' expectation. No-one has ever said out loud that FG craft are designed with redundancy to cope with 30% strength loss in 25 years before. That will make the 'boys in steel' sit up, I bet. Still, they rust just as quickly, and wooden boats are like the old family axe - had 4 heads and 7 handles, but lasted 100 years.
     
  13. PAR
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    PAR Yacht Designer/Builder

    Actually Rwatson, steel designs take a considerable amount of corrosion into consideration when developing scantlings. As much as 50% of the plate thickness may be solely to account for rust.
     
  14. mydauphin
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    mydauphin Senior Member

    Steel boat perform better over time, they get lighter... if you remove the rust.
     

  15. apex1

    apex1 Guest

    No, be calm, as the "boys in steel" are! Well protected (that is worldwide standard since 25 years) steel outlasts FRP by some magnitude. And wood is not worse, when well protected and maintained.
    In fact, under ideal conditions, the fatigue issues with FRP can make it the worst of all three!
     
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