In the professional world of coating applications, accurate estimation of coverage is critical. This guide will focus on the concept of 'mils' and its relation to coverage per gallon for various coating types.
What is a Mil?
A mil is one-thousandth of an inch and is a crucial measure in the coating industry, dictating how much area a specific volume of coating can cover. Understanding and applying the correct mil thickness is essential for the performance and economic efficiency of the coating, as well as correctly estimating jobs and required materials.
Coverage Estimation Formula
General Calculation: Coverage can be estimated using: Coverage (ft²/gal) = 1604 / Desired Thickness (in mils)
Example: For an epoxy base coat applied at 16 mils, the coverage would be 1604 / 16, or approximately 100 square feet per gallon.
Determining Mil Thickness from Coverage
Reverse Calculation: To find the thickness required for a specific coverage area: Thickness (mils) = 1604 / Desired Coverage (ft²/gal)
Example: For a high-wear urethane that covers 600 square feet per gallon, the thickness would be 1604 / 600, about 2.67 mils.
Practical Coverage Examples
Epoxy Base Coat: 100-150ft²/gal is equivalent to a 10-16 mil thickness
Polyaspartic Top Coat over Flake Broadcast: 130-150ft²/gal is equivalent to a 10-12 mil thickness
Coverage Chart
| Mil Thickness | Coverage (Sq. Ft. per Gallon) |
|---|---|
| 1 | 1604 |
| 3 | 534.67 |
| 5 | 320.8 |
| 10 | 160.4 |
| 12 | 133.67 |
| 16 | 100.25 |
| 20 | 80.2 |
| 30 | 53.47 |
| 40 | 40.1 |
| 50 | 32.08 |
| 100 | 16.04 |