Poxy-Shield and humidity

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John_C
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Poxy-Shield and humidity

Post by John_C » Sun Aug 16, 2015 3:23 pm

Hi,

I'm ready to start the fiber-glassing process. However, it's been fairly humid lately and it doesn't look like it will end soon. It's been in the low to mid 80s with 60-70% relative humidity, and Glen-L's Poxy-Shield directions state not to use in the resin in high humidity. Do you think the humidity levels in my area would be considered "high", or can I still achieve a strong bond in these conditions?

Thanks,
John

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Bill Edmundson
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Re: Poxy-Shield and humidity

Post by Bill Edmundson » Sun Aug 16, 2015 6:03 pm

John

I don't know where you are. It would help us if you added it to your profile.

That is pretty high humidity. It would probably work if you are not going for a clear finish (bright). Epoxy can get cloudy in high humidity.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

John_C
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Re: Poxy-Shield and humidity

Post by John_C » Sun Aug 16, 2015 7:20 pm

Thanks for the reply, Bill.

I'm in south-eastern Wisconsin. I live a couple miles from Lake Michigan so it gets pretty humid here in the summer.

The fiberglass will be painted over so clarity isn't an issue. As long as it's smooth and bonds well to the plywood it's fine.

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vupilot
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Re: Poxy-Shield and humidity

Post by vupilot » Sun Aug 16, 2015 8:43 pm

I agree with what Bill said. I've had trouble with clarity for bright finish in high humidity but not had trouble with bonding. After some experience I now prefer to do fiberglassing for bright finish with the MAS epoxy that Glen-L also now sells. It seems to stay perfectly clear in a wider range of humidity levels. If its going to be painted, no worries. I would apply it in the late afternoon when temperatures are steady or falling and not rising, this helps prevent a bunch of tiny gas bubbles as the epoxy cures which can be time consuming to sand away later.

John_C
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Re: Poxy-Shield and humidity

Post by John_C » Sun Aug 16, 2015 9:45 pm

vupilot wrote:I agree with what Bill said. I've had trouble with clarity for bright finish in high humidity but not had trouble with bonding. After some experience I now prefer to do fiberglassing for bright finish with the MAS epoxy that Glen-L also now sells. It seems to stay perfectly clear in a wider range of humidity levels. If its going to be painted, no worries. I would apply it in the late afternoon when temperatures are steady or falling and not rising, this helps prevent a bunch of tiny gas bubbles as the epoxy cures which can be time consuming to sand away later.
Thanks for the info!

If I do apply resin in the evening, would it matter if the temperature fell below the dew point before the resin has a chance to set up? Also I'm going to be fiber glassing inside my garage (Door and windows open of course) and it's supposed to rain on and off the next couple of days. Obviously the boat wouldn't come in contact with the rain. However, would the added humidity be a problem, or would I still be good to go?

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vupilot
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Re: Poxy-Shield and humidity

Post by vupilot » Tue Aug 18, 2015 8:16 pm

Youll want it to be pretty firm before the temp drops so much that it meets the dew point. A couple hours before sunset should give you enough time. I found working in the shade after 3pm or so and the temp was steady enough that I avoided the out-gassing bubbles.

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