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Film thickness describes a dimension, not a complete measure of protection. Wet-film and dry-film values differ, and meaningful comparisons require a defined measurement method and product-specific context.
Wet film and dry film
Wet-film thickness is measured soon after application while liquid is present. As volatile components leave or the material cures, the final dry film may be thinner or otherwise change. The relationship depends on solids content and chemistry; do not derive it without product data.
Microns and mils
One micron is one-thousandth of a millimeter. One mil is one-thousandth of an inch; one mil equals 25.4 microns. These units are often confused. Check whether a manufacturer reports wet or cured thickness and whether the value is a target, range or measured result.
Measurement matters
Methods can include gauges or cross-section analysis suitable for the material and substrate. Surface curvature, texture, coating hardness and test procedure affect readings. Ask how the number was obtained, how many locations were measured and what variation is expected.
Thickness is not performance
A thicker layer is not automatically tougher, clearer or more durable. Adhesion, flexibility, toughness, defect sensitivity and exposure all matter. Compare thickness alongside relevant standardized tests and installation controls.
Related questions
What is wet-film versus dry-film thickness?+
Wet-film thickness is measured before drying or curing; dry-film thickness is measured after the process. They are not interchangeable.
How is PPS tested?+
Tests should match the claim and report the method, substrate, conditions and results. Demonstrations are not standardized tests.
References and further reading
- ASTM D3359 — Standard Test Methods for Rating Adhesion by Tape Test.
- ASTM D523 — Standard Test Method for Specular Gloss.
- ASTM G154 — Standard Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Materials.
Consult the current published editions and confirm that a method is appropriate for the substrate and claim. Listing a standard does not imply that LIQVIX or any other product has been tested to it.
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