Typical smooth powder finishes run about 2 to 3 mils (50 to 75 microns), textures 3 to 5 mils, and FBE or thermoplastic films much thicker. Film build is read with magnetic-induction gauges on steel and eddy-current gauges on aluminum, after cure or on uncured powder with an ultrasonic gauge. Too thin hides poorly and leaves more orange peel; too thick costs money, invites back ionization and gassing and chips more easily.
Film build is all over the place, 1.8 on the faces and 6 on the edges, check the recip settings.
Measure film build on the edges and in the recesses as well as the flat faces, because that is where the out-of-spec readings hide.
Also heard as
- DFT
- dry film thickness
- build
Related terms
Mil
One thousandth of an inch, exactly 25.4 microns, the everyday unit for coating thickness in North America.
Orange peel
A dimpled surface texture like the skin of an orange, the most common appearance complaint on powder.
Theoretical coverage
The area one pound of powder covers at one mil if every particle lands on the part.
Picture framing
A visible border of heavier or darker coating around the edges of a flat panel.