Cold temperatures will slow down the epoxy reaction and in the extreme cold, the reaction can stop altogether. The gel time and full cure time will be extended in cool temperatures. All of our published gel times are based on a room temperature cure of 77 deg F (25 deg C), a general rule of thumb is that for every 18 deg F (10 deg C) drop in temperature the gel time is doubled. Some epoxies can develop an amine blush when applied in cooler temperatures as well.
The most common question we receive is when a customer wants to work on a project in the cooler months and the temperatures will drop below the product application temperatures at night. In these cases, we recommend applying the epoxy in the warmest part of the day when temperatures will be above the working temperature for as long as possible. When applied this way, most of the reactions can take place as intended. The final part of the reaction will resume when the epoxy warms back up in subsequent days. If an amine blush develops an extra step of washing the coat with warms soapy water before moving on to subsequent coats will be required. Also, the extended gel time can lead to a greater chance of dust and other debris settling into the coat.
If the initial temperature is below the recommended application temperature or if the temperature is not expected to warm back up in the following days, we would suggest utilizing a hardener that is formulated for cold conditions. (#1 Fast, SilverTip Fast, Cold Cure, T-88).