(A) Chalking

Identification:

A chalky deposit on the surface which can be removed by a slight application of pressure.

Description:

The entire coating surface turns into a powder after a period of exposure. The binder disintegrates by the active rays of the sun and leaves residues of pigments on the surface. The process of chalking is accelerated by alternate wet-dry cycles and improper mixing ratio of pigment to binder.

Fortunately, the coating film underneath the chalky surface remains intact. The process is very slow which affords a chance of repair before the damage reaches the substrate.

Prevention:

• Remove the powder from the surface

• Apply chalk resistant binders such as acrylics and polyurethanes in a proper ratio with pigments.

• Do not add more than the recommended quantity of thinners.