Air bubbles in an epoxy floor can appear in the finish as isolated, small and dark pinheads – however in some instances they can occur in much greater diameters and even in large clusters! While air bubbles will rarely affect the floor’s functionality or durability, they can significantly diminish the floor’s visual appeal.

In most cases, the bubbles are caused by air entrapment during the mechanical mixing of a resin system’s component parts. If the mixing action is too aggressive, such as a power drill set at over 600 rpm, it will lead to the formation of small, entrapped bubbles that are hard to break and which will form into the unwanted pinheads as the epoxy coating dries.

Causes and Cures of Air Bubbles

1. Mixing: Improperly mixing, casting or moulding a resin floor coating can lead to bubbles forming in the finish. Cure: Make sure to use the equipment that is recommended by the manufacturer during the mixing and application processes. In particular, use a Jiffy mixer at slow to medium speeds when mixing the coating, and if air bubbles are still present allow the resin product to sit briefly before pouring.
2. Temperature: If it’s too hot or humid when the floor is being applied then it can result in rapid drying that will also subsequently cause air entrapment (and hence bubbles) in the coating. Cure: Make sure that the ambient temperature in the area being coated is kept cool and that the humidity is maintained at the recommended levels during the application and while the floor is curing.
3. Sunlight: Direct sunlight can cause an epoxy floor to become tacky before enough of the air has been released. Cure: Cover windows and doorways to prevent the new floor from being exposed to direct sunlight until it has fully cured.
4. Air Movement: Air moving quickly over a freshly laid epoxy floor, such as from fans, doors or vent, can cause flash drying and result in bubbles. Cure: Take care to ensure that anything that might generate fast air movement is removed from the environment, in fact if it’s possible to suck air out of the area using ventilation then this will be advantageous.
5. Substrate: An absorbent substrate or one that releases an excessive amount of moisture can cause a variety of issues, including bubbles. Cure: Analyse the substrate and make certain that the concrete is properly dried prior to applying the coating.

In general an epoxy floor installation should remain bubble free so long as the proper surface preparation methods are employed, the mixing method is appropriate and the coating is laid within an environment that is not excessively warm, humid, windy, sunny or damp.