West System fast set (205) Epoxy set-up failure

Discussion in 'Materials' started by SpiritWolf15x, Nov 26, 2012.

  1. SpiritWolf15x
    Joined: Apr 2010
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    SpiritWolf15x Senior Member

    Hi all, I was doing some repairs on my powerboat back in October using Westsystem 105 Epoxy with 205 fast hardener and 403 filler. I followed the ratio chart and it seemed like it was mixing properly.

    I had to leave the repair to set and could not check on it until last weekend (Nov 24). The mix had not set at all properly leaving me with a semi set goopey, snot like mess. It had been raining a lot between then and when I checked it but the repair wasn't exposed in any way and despite the temperature dropping to about 1 or 2 degrees a few times I was sure it'd set up properly while it was still about 7 or 8 degrees at night during the last dry week of October.

    My question is, how do I go about fixing this? Has this happened to anyone before?

    Pictures coming eventually...
     
  2. DCockey
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    DCockey Senior Member

  3. SpiritWolf15x
    Joined: Apr 2010
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    SpiritWolf15x Senior Member

    I'd say the warmest the repair has been was back in october when it was still 15-16 degrees Celsius during the day and about 5 at night. It was like that and dry for about a week after the repair.
     
  4. DCockey
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    DCockey Senior Member

    Was that an outside air temperature of 15-16 C during the day and about 5 C at night? Is the repair exposed to the atmosphere? Is it shaded? Boat in the water or on land?
     
  5. DCockey
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    DCockey Senior Member

  6. DCockey
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    DCockey Senior Member

    How did you measure and mix the epoxy?
     
  7. SpiritWolf15x
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    SpiritWolf15x Senior Member

    Following the directions on the tin and the measure lines on the cup, standard 2:1 mix with about MAYBE a 1/4 of a cup of filler? If that.
     
  8. DCockey
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    DCockey Senior Member

  9. SpiritWolf15x
    Joined: Apr 2010
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    SpiritWolf15x Senior Member

  10. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    MAS epoxy is 2:1 ratio. Different epoxies have different ratios. Some West System is 5:1, some 3:1.
     
  11. SpiritWolf15x
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    SpiritWolf15x Senior Member

    OH well, more work for me to do.
     
  12. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Yep, 205 is a 5:1 and it'll never cure with a 2:1 ratio. Scrap clean, then remove all remnants of uncured goo and start over with a clean slate. If any of the first attempt is still on the surface, you'll have a lousy bond.
     
  13. pauloman
    Joined: Jun 2010
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    pauloman Epoxy Vendor

    my friend PAR is pretty much right on, but you don't have to get 100% of the old stuff off. A little 'sticky' film is OK. The correctly mixed epoxy will be able to 'fix' the little bit of goo left behind. - Maybe I would say you need to remove 95% of the mess.... Generally you can be off ratio with epoxy by about 15-20% before you have problems, that is why the fresh epoxy can 'cure' a bit of off ratio stuff next to it. Note that I might be more concerned about 100% clean surface if it was a life or death type situation.

    we have epoxies that can be used in temps down to freezing (but cannot ship to canada)

    Everyone screws up from time to time - often the cause cannot ever be explained, even with hours and hours of debate and talk..... At least here we know it was a mix ratio issue (it is also common to get the ratio backwards, 1:2 instead of 2:1)

    paul oman
    progressive epoxy polymers inc.
     
  14. Submarine Tom

    Submarine Tom Previous Member

    Remember, when all else fails, read the instructions.

    Sorry for your misfortune.
     

  15. rwatson
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    rwatson Senior Member

    Yes, and the local West Systems retailer knows one carpenter who got it backwards 5 of hardener to 1 of epoxy. :)
     
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