Humidity and Blush/Curing

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jbo_c
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Humidity and Blush/Curing

Post by jbo_c »

I took next week off to work on my build and, of course, we’re forecast for overcast, rainy, humid weather most of the week. Rescheduling the time off isn’t an option. So . . .

1. I’ve always understood that humidity increases opportunity for blush.
2. I typically try to work wet on wet or wet on green when planning is possible to avoid concerns over washing/sanding between coats/layers. Wet on green” for me means maximum of 24hrs between coats.
3. I’m using MarinEpoxy slow(which I’ve never experienced blush with).
4. I’ll be working under a pole barn, so outside, but protected from direct rain impact.
5. Temps expected to be low 60s to low 80s.(I know, slow hardener not necessary at these temps, but it’s usually hotter, so that’s what I have.)

Should I take extra precautions to avoid blush? Like shorter maximum recoat times or only work wet on wet? Or should I just soldier on as usual and stop overthinking?

Thanks.

Jbo

TomW1
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Re: Humidity and Blush/Curing

Post by TomW1 »

Jbo I have never heard of anyone experiencing blush with slow hardener. I would not worry about it. But of course, do as much wet on wet as you can. Tom
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fallguy1000
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Re: Humidity and Blush/Curing

Post by fallguy1000 »

Stop overthinking. Every morning do the finger test for greasy blush, wash if needed.
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Jaysen
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Re: Humidity and Blush/Curing

Post by Jaysen »

fallguy1000 wrote: Sat May 20, 2023 3:52 pm Stop overthinking. Every morning do the finger test for greasy blush, wash if needed.
This.

And be very clear. WASH do NOT sand or scrub blush into the epoxy. Use a mild detergent like simple green if you have any stubborn spots. A microfiber rag is about as aggressive as you want to get.

You really have nothing to worry about if you are using BBC epoxy though. Even the fast is pretty blush free.
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jbo_c
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Re: Humidity and Blush/Curing

Post by jbo_c »

Yes. BBC epoxy.

And sorry for my lack of clarity. I meant to refer to sanding between coats once full cure had been reached.

Thanks, all for the advice. I’ll proceed as planned.

Jbo

fallguy1000
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Re: Humidity and Blush/Curing

Post by fallguy1000 »

jbo_c wrote: Sat May 20, 2023 8:10 pm Yes. BBC epoxy.

And sorry for my lack of clarity. I meant to refer to sanding between coats once full cure had been reached.

Thanks, all for the advice. I’ll proceed as planned.

Jbo
I always sand if the cure happened overnite. I have had zero blush incidents using Silvertip, but I am climate controlled.
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jbo_c
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Re: Humidity and Blush/Curing

Post by jbo_c »

Based on Jacques’ past statements, I’ve never done additional prep as long as it’s been less than 24 hours since the last application of Marinepoxy(usually 14). Has never let me down.

In fact, I have been known to put another coat on last thing in the evening just to make sure it hasn’t been too long if it will be the next afternoon before I can get to work. Costs a little more in epoxy, but saves the time and effort sanding - I can just come in and get to work.

Jbo

Dougster
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Re: Humidity and Blush/Curing

Post by Dougster »

Four boats, silvertip and marinepoxy---never saw a blush.

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Re: Humidity and Blush/Curing

Post by BarraMan »

I used West System epoxy with slow hardener, in a high humidity environment - never saw any blush!

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