The winter months can be tough ones for coatings contractors, especially those who install epoxy coating systems. Although epoxy typically is best suited for application in temperatures above 55°F, there are ways to successfully install epoxy during cold weather. Here are a few tips to help ensure that the epoxy coating application process goes smoothly even when the temperature plummets.
How the Cold Affects Epoxy
Before we delve into the ins-and-outs of applying epoxy when the temperatures drop below 55°F, it is important to understand why temperature is such an important factor in the proper application of epoxy floor coatings. When epoxy resin and hardener are mixed together, a chemical reaction is started. This reaction produces heat and is called an exothermic reaction. The ambient, or surrounding temperature, affects the mixture’s temperature, its rate of reaction and degree of cure. Warmer ambient temperatures accelerate the chemical reaction, while colder temperatures slow the reaction down, directly affecting the cure time of the epoxy.
In addition, ambient temperature has an effect on the handling properties of epoxy resin. As the temperature drops, epoxy becomes much thicker and will not flow out easily. This means that it is much more difficult to meter and mix the resin and the hardener which can lead to inaccurate metering, incomplete mixing and a greater risk of an insufficient bond to the substrate. Thick epoxy is also much harder to apply, resulting in uneven layers of coating material and the creation of air bubbles.
Tip #1: Warm it Up
So, how can a coatings contractor ensure that epoxy floor coatings are properly applied in cold temperatures? The key is to add some heat to the situation. First, whenever possible warm the ambient air by turning up the thermostat in the application area or use radiant heaters to keep the temperature from dropping too low.
Second, warm the material. The warmer the material, the lower the viscosity of the epoxy resin. As mentioned above, thinner resin and hardener will flow better, ultimately leading to a better bond with the substrate. In addition, keeping the epoxy resin and hardener warm will get the initial chemical reaction off to a better start, even if the mixture cools after it is applied to the surface. Storing the material in a temperature-controlled area near the application site and/or warming it with heat lamps are two ways to make sure the epoxy and the hardener stay at an optimum temperature.
Tip #2: Don’t Forget the Slab Temperature
With the ambient temperature and the material at a balmy temperature, it may seem that everything is on the right track. However, there is one other critical element – the temperature of the substrate to be coated. Warming the surface of the slab with portable heaters, hot air blowers, and/or heat lamps will ensure that the material flows smoothly, penetrating porous surfaces and creating a strong bond with the substrate.Hot Air Blower, Photo courtesy of Leister.com
It is extremely important to note that daily variation in temperature can also create issues for epoxy coatings. When overnight temperatures drop well below daytime temperatures, moisture contamination problems can occur. Water vapor can condense on a cooler surface and affect the adhesion and cure of the epoxy that is applied over it. To avoid this potential problem, the application area should be kept at a fairly constant temperature. If this is not possible, then the surface should be allowed to come up to the air temperature prior to the application of epoxy.
Tip #3: Use The Right Product
It is also important to use the right epoxy products when applying coatings in cold temperatures. For example, PlexiGlaze IFF “Cold Set” is specially formulated for cold area applications when temperature cannot be maintained over 50°F. Always look carefully at the epoxy coatings tech sheet for information about whether or not the material can be applied in temperatures under 55°F.
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