How To Use Paint Mixing Cups For A Better Finish

When it comes to painting your project, one of the most confusing steps for many first-time painters is how to accurately mix all of the different components. In addition to the urethane base coat or clear coat you’re using, you’ll need to add an activator (sometimes called a catalyst or hardener) and perhaps a reducer to help it lay down more evenly or even a fisheye-eliminating surfactant. Each paint material has its own specific chemistry that requires precise proportions of each component in order to achieve results worth showing off.

Mixing cups are a convenient way to get the proportions just right, but understanding how to use them can challenge a novice painter. What exactly do all those different marks mean and which one do you even use? The answers are quite simple if you follow the steps below.

MIXING YOUR PAINT

Choose your paint – The paint system you choose for your project will dictate what proportions of other components you’ll be adding. For instance, if your color coat is a 4:1 finish, you’ll be mixing four (4) parts paint to one (1) part activator. You may finish with a 2:1 clear coat, meaning you’ll use two (2) parts clear base to one (1) part activator. Always use the correct-ratio activator for a given base material.

Choose the right mixing cup – Estimating how much material you’ll need for a spray job can be tricky, and it’s something that’s learned with experience. When in doubt, it’s better to mix more material than you’ll need rather coming up short near the end of a project. Mixing more paint partway through a sprayout can lead to inaccurate measurements if you rush. You may also encounter poor blends if too much time passes between sprays.

Paint mixing cups come in a variety of sizes to accommodate different sizes of projects. If you’re spraying a whole body in a single pass, you may need to blend a couple quarts or more. If you’re just hitting a bumper or some other single panel, maybe only a few ounces will do the job.

Find the correct ratio on the paint cup – Now that you’ve selected your mixing cup, find the appropriate mixing ratio on the side panel. The cup may be marked with several ranges for a given base ratio, depending on whether you’ll be using additives like reducers or fisheye eliminators. For instance, in addition to a 4:1 range for the base materials, you may also see a 4:1:1 or even a 4:1:1:1 to accommodate other additives.

The first number in the range (from left) is for the base material and the second is for the activator, with subsequent numbers being used for other additives. refer to instructions on each component’s label to determine the correct amount to use.

Pour your base material to the desired level – Once you know which range you’ll be using, you can begin pouring materials into the cup from left to right. You’ll see graduations marked between 1 and some other number, usually between 4 and 9 If you plan to fill the cup. Add your base material until it reaches the maximum number (for this example we’ll say 5) in the first column. If you plan to fill only part of the cup, only fill up to the line for that final amount you’ll be mixing.

Pour your activator – Add your activator to the cup until the total material in the cup reaches your desired level (again for this example, 5) in the second column.

Pour additional components – If they’re required, add any reducer/thinner/extender and/or fisheye eliminator to match the same desired level in the third and/or fourth columns.

Mix your paint and spray – Once you’ve added all your components, you can stir your paint and prepare to spray. You’ll now have an activated mixture with a finite pot life. How long the paint remains sprayable depends on a number of factors. Ambient temperature, volume, the speed of the activator, and many other things will affect its active window. Just be aware the clock is ticking.

If you’ve mixed more paint than your gun can hold, put a lid on your mixing cup until you’re ready. This will help prevent a skin from forming on the top of the paint and will also keep dirt, bugs, and other contaminants from entering.