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 Magnetic Dry Film Thickness Gauge |
 Wet Film Thickness Gauge |
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Economics of Painting: In estimating the cost of a paint job or comparing the cost of one paint to that of another, factors other than the cost per gallon must be taken into consideration. These additional factors include coverage rates, material cost per square foot, cost of surface preparation and application, expected service life, and cost of money. The true cost of painting is the cost per square foot per year of protection. As a rule of thumb, only 20-25 percent of the cost of painting is due to materials, the balance going for surface preparation and application. Coverage Rate and Material Cost Per Square Foot: One gallon is equivalent to 231 cubic inches. If this volume is contained in a cube, it would measure 6.14 inches on an edge. If the cube were compressed to a thickness of 1 mil (.001 inch), it would cover an area of 1,604 square feet. If exactly one gallon of paint were poured out on a perfectly smooth, flat surface at 1 mil WET thickness, it would cover an area of exactly 1,604 square feet. But most paints contain a significant fraction of their volume as volatile solvent that must be taken into account. If the above paint has a 50 percent volume solids, when the 1 mil wet film dries, its film thickness would be 0.5 mil. At 30 percent volume solids, dry film thicknes would be 0.3 mil. Or, to determine the area covered at 1 mil DRY film thickness, multiply 1,604 square feet by volume solids fraction:
For film thicknesses other than 1 mil, divide the coverage rate by the desired film thickness. To find the coverage rate for a 50 percent volume solids coating applied at 5 dry mils:
For actual coverage rates, allowances must be made for such factors as surface irregularities, anchor pattern, film thickness, variance, loss, overspray, and incomplete usage. The following factors have been found in actual use to be reasonable estimates of the loss factors which can be expected:
When spraying in high winds or on small, complicated surfaces, loss can be 50 percent or more. To obtain the material cost per square foot, divide the gallon cost by the coverage rate. Film Thickness Chart | Cost Per Square Foot Chart Home |Surface Prep | Product Lines | Safety Info
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