Can you mix brands of polyester resin?

Discussion in 'Fiberglass and Composite Boat Building' started by PNW_Dave, Jan 31, 2020.

  1. PNW_Dave
    Joined: Jan 2020
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    PNW_Dave New Member

    I just started laying up a project using Orca 200 polyester resin and realized I won't have enough resin to get as many layers as I need. Its Friday and my local Fiberlay shop is closed on the weekends so I can't get more of the Orca 200.

    There are a few boating shops open on the weekend (like West Marine) that carry their own poly resin. Can I finish the job with one of these while I'm still within the curing window?
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    If it is "general purpose" polyester, I don't see a great problem, but is the original waxed or unwaxed ?
     
  3. PNW_Dave
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    PNW_Dave New Member

    Yes it's general purpose and unwaxed. I assume match those characteristics with the other brand?
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    There shouldn't be any great issue, but if in doubt, scuff the surface with sandpaper before applying the new.
     
  5. PNW_Dave
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    PNW_Dave New Member

    Hope not because I'm 2 layers in on the new stuff! There wasn't really another option though. I grabbed some West Marine "Polyester Boaters Resin" - gen. purpose and unwaxed. Fingers crossed.

    ...this stuff gels up a good 5-10 min faster which through me off. It started kicking as I was halfway through soaking a piece of CS. Luckily I ripped it up right before it set.
     
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  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Well, I wouldn't be too worried, is possible one has more accelerator than the other, or possibly you used a little more catalyst ?
     
  7. PNW_Dave
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    PNW_Dave New Member

    It does ask for more "hardener" than the Orca 200 did. 12 drops / oz. compared to 8. Is slowing it down as easy as reducing the amount I mix in?
     
  8. Mr Efficiency
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    Mr Efficiency Senior Member

    More catalyst, less gel time. You don't want too little though, much depends on ambient temperature, and laminate thickness, a thick laminate will cure faster.
     
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  9. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    You can mix and match resins without a problem chemistry wise.

    You shouldn’t drop below about 1% on the catalyst ratio.
     
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