Epoxy and PR questions

[Haynie]

How does heat affect working time? It gets hot here and my shop is not cooled. What should I expect with the hot and very dry weather?

 

[Russianwolf]

heat reduces working time for both.

optimal temps are usually in the 70-80 range.

 

[Haynie]

Well poop. I will be doing this in the 90-110 range. I know the epoxy will work in this environment because we have used it on boats. We fiber glassed as well but that was not casting resin. Is casting resin the same as what we used for fiber glass?

 

[Justturnin]

I have cast pr in 100 degree weather here. The humidity is high over here but I think that would be more of an issue on my side than it being dry.

 

[Russianwolf]

that doesn't say that you can't cast at those temps, just that the working times that are listed for the resins tend to be in controlled environements in the 70-80 range.

Some like to heat the resin so that it flows more smoothly and is easier to mix, but once mixed the working time is shorter too because of the additional heat.

casting PR in that temp, you will likely want to reduce the catalyst so you don't overheat the resin making it more brittle.

I'm moving to an epoxy myself, and I cast in a shed in direct sun. I may be able to move back into the shop since this doesn't seem to off gas like PR does. But for now, the shed is where its at and temps inside I know get over 100. hasn't stopped me, just means I have to make some adjustments.

But the working time will be shorter than if casting at 80.

 

[Haynie]

Thanks.