AIR BUBBLES IN THE COATINGAir bubbles may appear in the coating as
small defects or honey comb clusters. In nearly all cases, they are caused by
air entrapment in the coating or applied film. |
| PROBLEM |
SOLUTION TO PROBLEM |
AVOIDING PROBLEM |
| OUTGASSING - Air can escape from porous concrete and be trapped in
the coating surface. |
Either roughen with 60 grit screen or break larger craters and fill with
100% solids material. Vacuum and apply another coat. |
Apply a suitable primer to seal off the air in the concrete. Usually a low
solids high penetrating primer works best. |
| AIR MOVEMENT - Excessive air movement from vents, doors or other
sources may cause flash drying and prevent air release. |
Either roughen with 60 grit screen or break larger craters and fill with
100% solids material. Vacuum and apply another coat. |
Avoid any condition that can generate fast air movement across the coating.
Always suck air out vs. blowing with exhaust fans for ventilation. |
| TEMPERATURE / HUMIDITY - Too hot or too humid conditions can result
in rapid drying conditions and result in air entrapment. |
Either roughen with 60 grit screen or break larger craters and fill with
100% solids material. Vacuum and apply another coat. |
Wait until the temperature and humidity are within the ranges as needed to
properly apply the material. |
| DIRECT SUNLIGHT - Floors exposed to direct sunlight can tack off
before sufficient air release has occurred, forming bubbles. |
Either roughen with 60 grit screen or break larger craters and fill with
100% solids material. Vacuum and apply another coat. |
Close all doors where the sunlight can hit the floor and coat the areas
exposed to the sunlight before the sunlight hits that area. |
| IMPROPER MIXING - Do not entrap air into the coating by using fast
speed mixing equipment or improper mixing procedures. |
Either roughen with 60 grit screen or break larger craters and fill with
100% solids material. Vacuum and apply another coat. |
Use slow speed mixing equipment with a paddle type blade. If air is embodied
into the material, let stand until air is visibly released. |
| ROLLER COVERS - Too short or too long of a nap roller can cause air
to be generated into the coating causing air bubbles. |
Either roughen with 60 grit screen or break larger craters and fill with
100% solids material. Vacuum and apply another coat. |
Use the appropriate length nap roller and apply without vigorous rolling.
Use an air removal tool to remove air entrapped if necessary. |
| MOISTURE / HIGH HUMIDITY - Some urethanes are sensitive to moisture
in the concrete or excessively high humidity, causing bubbles. |
Roughen with 60 grit screen if the problem is minor or remove affected areas
by grinding prior to recoating the area. |
Make certain that the concrete is properly dried and the humidity is at the
recommended levels before applying the
coating. |
