Understanding the Importance of Film Thickness
OEM Film Builds
The dry film build, or dry film thickness (DFT), is the measurement of the total cured paint layer in microns (µm) or mils. It is important that film builds are kept within the specifications provided by original equipment manufacturers (OEM) and paint manufacturers.
Paint film thickness gauges are available from various equipment manufacturers, and they are simple and easy to use. It should be standard practice to check the DFT during the initial vehicle inspection, prior to commencing repairs.
Excessive Paint Film Thickness
An OEM paint finish has a thickness of approximately 90-120 µm, which is around the same as a strand of human hair. When refinishing vehicle parts, it is recommended that a paint finish of 300 µm or greater should either be removed completely or sanded back to an allowable tolerance. This ensures that the refinished surface will not exceed the allowable limit.
Excessive paint film thickness can cause durability problems such as:
- Cracking
- Excessive stone chipping
- Loss of gloss
- Sinkage
- Pickling
- Delamination