On Saturday, March 11, 2017 at 11:26:29 AM UTC-5, trader_4 wrote:
On Saturday, March 11, 2017 at 11:14:05 AM UTC-5, Chuck wrote:
replying to Don Klipstein, Chuck wrote:
20 degrees F is roughly 30 degrees C below a fairly normal room
temperature.-----that does not make sense. 30C is 86F so you are saying a
fairly normal room temp is 106F. I would say that 20F is 9C below a normal
room temp of 20C. So do your calculation using the number 10. In your example
you use 5 minutes. Double that once for an answer of 10 minutes

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Not that it really matters, because the post you're replying to is 9 years
old, but what he said was that 20F is roughly 30 degrees C BELOW normal
room temp. That is correct. 30 centigrade degrees is 54 F degree units.
20 + 54 = 74F. Or the other way of looking at it is 20F = -7C,
-7C + 30C = 23C = 74F (room temp)

But I wouldn't count on epoxy hardening correctly at 20F period.
I'd put a small heater on it until cured.

There are hardeners formulated for cold weather, such as West Systems 205,
but even that is only speced for "as low as 35°F".

As far as using a heater, there is a technique known as post-curing which
calls for applying heat after an partial cure at ambient temperature.
Applying heat too soon or too fast can cause out-gassing and bubbles in
the cured coating.

Lots of info and techniques can be found in this doc:

http://www.westsystem.com/ss/assets/...neversion..pdf