Sealers And Coatings TROUBLE SHOOTING GUIDE to Air Bubbles
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By Tim Frazier, Lead Trainer and Technician
AIR BUBBLES IN THE COATING: Air 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.
Cause 1: OUTGASSING – Air can escape from porous concrete and be trapped in the coating surface.
AVOIDING PROBLEM – Apply a suitable primer to seal off the air in the concrete. Usually a low solids high penetrating primer works best.
Cause 2: AIR MOVEMENT – Excessive air movement from vents, doors or other sources may cause flash drying and prevent air release.
AVOIDING PROBLEM – Avoid any condition that can generate air movement across the coating.
Cause 3: TEMPERATURE/HUMIDITY – Too hot or humid conditions can result in rapid drying and air entrapment.
AVOIDING PROBLEM – Wait until the temperature and humidity are within the ranges as needed to properly apply the material.
Cause 4: DIRECT SUNLIGHT – Floors exposed to direct sunlight can accelerate before sufficient air release has occurred, forming bubbles. Sunlight can cause your surface to heat up and have excessive out gassing.
AVOIDING PROBLEM – Close all doors where the sunlight could hit the floor, cover windows and coat the areas exposed to possible sunlight before the sunlight hits that area.
Cause 5: IMPROPER MIXING – Do not entrap air into the coating by using fast speed mixing equipment or improper mixing procedures.
AVOIDING PROBLEM – Use slow speed mixing equipment with a paddle type blade. If air is embodied or vortexed into the material, let stand until air is visibly released.
Cause 6: ROLLER COVERS – Too short or too long of a nap roller can cause air to be generated into the coating causing air bubbles.
AVOIDING PROBLEM – Use the appropriate length nap roller and apply without vigorous rolling. Use an air removal tool to remove air that is entrapped if necessary.
Cause 7: MOISTURE/HIGH HUMIDITY – Some sealers are sensitive to moisture in the concrete or excessively high humidity’s, causing bubbles.
AVOIDING PROBLEM – Make certain that the concrete is properly dried and the humidity is at the recommended levels before applying the coating.
Never hesitate to give us a call if you are experiencing this problem. We want your jobs to turn out as planned and sometimes, you just need a little help and a good technician to give you a hand. 888-848-0059
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