Epoxy 7 day window

L

Lone Star

Promoted Users
How is the 7 day window effected by the 105 degree heat days? Around here its in the 90's at midnight and I am wondering does this high heat shorten the window for epoxy and if so what do you recommend.

Especially for applying filler and not sanding etc.
Wait times may change?

Your thoughts
 
It shortens it , by how much , not sure. Here last year when it was 90* for about two weeks I noticed the left over primer in the cup had started to set up quicker than normal. Usually I could get about three days in a sealed cup but by next afternoon it had started to turn to a solid. What most people don't think about is that most things are tested at 70*. So of course the higher temps will shorten the open window.
Also under normal circumstances I usually would sand anything over three days.
 
elwood said:
It shortens it , by how much , not sure. Here last year when it was 90* for about two weeks I noticed the left over primer in the cup had started to set up quicker than normal. Usually I could get about three days in a sealed cup but by next afternoon it had started to turn to a solid. What most people don't think about is that most things are tested at 70*. So of course the higher temps will shorten the open window.
Also under normal circumstances I usually would sand anything over three days.
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Elwood I noticed my left over epoxy had already setup over night in the mix cup and usually it takes 2-3 days. Sanding on the second day was like it was a several days old too. I could tell a difference on filler bite on the second day but the next day seemed about the same but I scuffed with maroon pad anyway. Just a reminder for those out there in the heat and using the 7 day window data.
 
Barry has said temperature doesn't really matter. It is still seven days. Seeing you are going to apply filler, Do one spot as a test if you are concerned. As you are sanding note how it is featheredging. If it is nice and smooth and you can't lift the filler edge with your fingernail, then it is OK. I'll go out on a limb and say that if you are still in the original window then you will be fine.
 
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Urethane, temperatures matter. Every 15 degree increase shortens cure time by half. Epoxy is not the same and the urethane rules don't apply. UV light is the main factor in accelerating the cure with epoxy. Heat is not.
 
idk, i am very leery of epoxy recoat windows. i have had adhesion issues with many different epoxies in the past when waiting too long. not just spi. for filler, 2k primer or single stage, if its sanded i would give it 5 days max. i have never given the epoxy a 7 day window even when its cold. a good polyester base i would never let the epoxy go more than 36 hrs max
 
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Jim C said:
idk, i am very leery of epoxy recoat windows. i have had adhesion issues with many different epoxies in the past when waiting too long. not just spi. for filler, 2k primer or single stage, if its sanded i would give it 5 days. i have never given the epoxy a 7 day window even when its cold. a good polyester base i would never let the epoxy go more than 36 hrs max
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I agree, always best to error on the side of safety.
 
Maybe @Barry can clarify. I was speaking to the OP's question about filler. All I know, being I never re-coat it without sanding unless it's 24-48 hours and applying filler, 2K, or Polyprimer.
 
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