Epoxy resin reacts to the environment in which it is mixed/applied. There are several factors that can lead to a cloudy, milky or translucent finish. These include small bubbles forming under the surface when used when the temperature is too cold. (Applying heat during curing may straighten this out.) Cloudy or dull epoxy is typically caused by excessive moisture. Specifically, moisture from excessive humidity in the area where the epoxy was applied or excessive moisture in/on the application surface. It can also be caused by moisture that has gotten directly into the mix of epoxy, but this is a rare occurrence.
There are a few simple ways to avoid this issue:
- Be sure to eliminate all water before applying epoxy
- Never apply epoxy when relative humidity is over 75%
If you do have an issue with cloudy epoxy there are a couple of ways to correct it. Once the epoxy has fully cured, test the problem area with a water-moistened rage to see if the cloudiness can be “wet out.” If it works simply wipe down the entire area. If the cloudiness cannot be wet out you will need to lightly sand out the cloudiness and apply a thin new coat of epoxy.