Ask the Expert Question-and-Answer Archive

by Ron Joseph

October, 2003

Dry Film Thickness of Paints and Coatings

Q. Are there any advantage or disadvantage, if the DFT coating on any applied surface becomes more or less thickness than specified?

A: Yes, when the film thickness is too thin then the coating does not properly protect the substrate. In the case of a metal corrosion can take place prematurely. When the film thickness is too high the coating can blister or become brittle. On the other hand, if more than one coat of paint is applied and if you allow sufficient time between coats, then the advantage of the high film build is that you will get better protection of the substrate.

Q. How do you know the required DFT to any surface (metal wood, masonry)?

A. The paint vendor (manufacturer) usualy tells you what the film thickness should be. This value, or range of values is given on the technical data sheet.