Definition - What does Blister Liquid mean?
A blister liquid is a type of liquid that has been pulled underneath a coating, which causes blistering on the coating's surface. A blister liquid moves underneath the coating from the exterior through a process called osmosis. A blister liquid can be detrimental to a coating.
Corrosionpedia explains Blister Liquid
When a blister liquid moves to the interior of the coating, two types of failure may occur. There could be isolated failures to wherever a blister liquid aggregates - an area known as a blister. There could also be a complete failure of the coating because a blister liquid, once between the coating and the base material, may exert enough pressure to cause the coating to lose adhesion.
The most common type of blister liquid is water. Water soluble salts trapped beneath the surface can attract blister liquids and pull them from the surface of the coating to the space between the coating and the base material. This is one of the reasons why it is extremely important to clean the base material prior to applying the coating - it becomes much more difficult for water to cause blistering and coating failure without any water soluble salts beneath the coating.