Definitions and Causes
Alligatoring/crocodiling: A term used to describe a pattern of cracking that resembles the scales of an alligator or crocodile. This type of cracking is typically caused by the aging or drying out of the paint or coating, which causes it to lose its elasticity and crack in a pattern that resembles scales. It is also commonly caused by applying a topcoat before the underlying coat has fully dried or cured.
Checking: A term used to describe a pattern of cracking that resembles a series of small, interconnected lines. This type of cracking is typically caused by the shrinking or contracting of the paint or coating as it dries. It can also be caused by exposure to extreme temperatures or weather conditions, as well as by applying a topcoat.
Examples of Alligatoring and Checking
Paint: Alligatoring in paint happens when a topcoat is applied over a still-drying basecoat, causing shrinkage and cracking resembling scales. Checking occurs under stress, like temperature changes, leading to more random cracking.
Wood: Wood alligatoring arises from extreme temperature or humidity, causing shrinkage and scale-like cracking. Checking in wood is a natural aging process, leading to small, shallow cracks parallel to the grain.
Metal: Metal alligatoring happens under extreme temperatures or stress, forming scale-like cracks. Checking occurs due to stress like bending, resulting in small, shallow cracks perpendicular to the stress.
The occurrence of alligatoring or checking varies depending on the context, requiring an understanding of their causes, appearances, and severities for appropriate solutions.
Exceptions in Paint Failure
Surface Preparation: Improper preparation, like dirty or greasy surfaces, can lead to alligatoring or checking even with correct paint application.
Weather Conditions: Extreme temperatures or high humidity during painting can cause improper drying or curing, leading to cracks.
Type of Paint: Oil-based paints are more susceptible to alligatoring, while latex paints to checking, due to their drying behaviours.
Age of Surface: Older surfaces, especially those exposed to elements, may require extra preparation like sanding to prevent cracking.
Application Method: Incorrect application, like uneven or improper thickness, can lead to drying issues and subsequent cracking.
How to Repair Them
To banish these eyesores, we need a fresh start. Grab your sanding equipment and buff away the old paint, revealing a clean slate. Primer, the unsung hero, takes centre stage next. It’s like the double-sided tape of the paint world, ensuring your new coat adheres flawlessly. Next, it’s time to ditch the brittle oil-based paints and rather use a flexible high-quality latex paint. This paint ensures durability and resilience against the tests of time and temperature. Chat to a knowledgeable staff member to ensure you select the correct products, ensure you have taken all the above information into account to prevent reoccurance and be sure to allow the correct drying time between coats.