Film Thickness
Guide to Film Thickness
A guide to film thickness and how it relates to coverage on an ideal surface. One"s actual coverage will vary and greatly depends on how smooth or absorbent a surface is, as well as how it is prepared and primed.
Film Thicknesses
When a material is applied in a thin layer it is generally referred to as a film. These films whether they are paint or plastic sheeting or paper can vary in thickness depending on how they are applied, manipulated or based on how their physical wet state properties dry. The thicknesses of these films are often measured in mil. A mil or one mil is equal to 1/1000th of an inch and should not be confused with a millimeter. Below is a list of everyday products and their thickness in mil.
- Grocery store plastic bag - 1/2 mil
- Human hair - 1-3 mil
- Retail store shopping bag - 2 mil
- Standard copy paper - 4 mil
- Paper dollar - 4.43 mil
- 30 lb bond paper - 6 mil
- Premium Glossy Photo paper - 10 mil
- Standard business card - 15 mil
- Standard credit card - 30 mil
- Penny - 60 mil
- Nickel - 75 mil
Often when dealing with paint films it is important to know how thick to make materials so they perform accordingly. In determining how much material is needed for a given product knowing the coverage of the product and the square footage needed to be covered can help in determining the amount of product needed to complete the task. Brushed paint application is approximately 5 mils or 300-400 square feet per gallon and as you increase your impasto you decrease your overall coverage.
| Wet Film Thickness (mil) | Wet Film Thickness (inches) | Wet Film Thickness (metric) | Coverage (sq. ft. per gallon US) | Coverage (sq. meters per liter) |
|---|---|---|---|---|
| 1 | 1/1000 | .0254 mm | 1604 | 39.3701 |
| 5 | 1/200 | .127 mm | 321 | 7.8784 |
| 10 | 1/100 | .254 mm | 160 | 3.9270 |
| 50 | 1/20 | 1.27 mm | 32 | .7852 |
| 100 | 1/10 | 2.54 mm | 16 | .3927 |
| 200 | 1/5 | 5.08 mm | 8 | .1963 |
| 1000 | 1 | 25.4 mm | 1.75 | .0429 |