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Outgas Bubbles – What is It? How to Prevent It?

February 11, 2019

An outgas bubble in a resinous coating is a term used to describe a type of visible surface defect found in the cured resinous coating after substrate outgassing. When outgassing occurs during the initial cure, any air pushed through the coating forms an outgas bubble that is captured in the setting resin. Outgas bubble appearance will vary depending on product composition, thickness, and the stage of cure during which the outgassing occurred, but typically present as small circles or tiny crater-like structures, often with a pin hole in the center of the circle or crater that may or may not be visible to the naked eye.

In order to minimize outgassing and prevent the formation of outgas bubbles, the substrate should be evaluated and any coating intended to seal the concrete should be applied when the substrate temperature is warmest and the slab temperature will be decreasing. This is because when the coating is applied to the substrate as the temperature is decreasing, the resins will be drawn into the slab sealing the pores and minimizing outgas bubbles. Note: There is no guaranteed way to prevent outgassing – this is intended only as a possible way to minimize the chances. Dur-A-Flex, Inc does not warranty against outgassing.

Rob Pacheco Jr.
Technical Manager – Northeast

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