How to Read Automotive Paint Mixing Cups

by Kimberly Johnson

Paint cups are used primarily in the automotive painting industry to achieve the correct mixtures of paint prior to application. Paint is never applied straight. It is first mixed with an activator solution and occasionally a third component like a paint thinner. Since paint manufacturers provide exact ratios for each of these products, the math can get tricky. That is why most people use mixing cups, which have all of the ratios written on the side, just like a measuring cup.

Step 1

Look on the side of the paint can to determine how much activator, or hardener, to add to the paint. The measurements will be displayed in a ratio such as 8:1:1. This means to use eight parts of paint, one part hardener and one part thinner. Some paint mixes leave off the third number since they don't require thinner.

Step 2

Hold up the paint mixing cup and locate the corresponding mix ratio along the top of the cup, in this case 8:1:1. You can look through the outside of the cup or the inside, as the ratios are printed on both the interior and exterior of the cup. Each ratio contains three adjacent columns on the cup, one for each of the three numbers. If the mix ratio only has two numbers, then ignore the third column.

Step 3

Place the mixing cup on a flat surface. Pour in paint until it reaches the line in the first column of the ratio; then stop. Using the 8:1:1 example, you will pour until reaching the number 8 in the first column.