Paints are divided into two broad categories: oil-based paint, also known as alkyd paint, and water-based paints, known as latex paint. Oil-based paint uses petroleum-based solvent as its medium, while latex paint uses water as its medium [source: JoePullaroInc].
There was a time when you could only spray with oil-based paints, since they were thinner than latex paint, did not dry so quickly and did not clog the spray gun's nozzle. But today’s latex paints are made of new synthetic resins, which are compatible with water, have a thinner consistency and are wet enough to be used in a spray gun. Today you can use an airless gun or aerosol can for spray painting with latex paint. However, you still may find that your latex paint is too thick for your spray gun's nozzle and needs thinning. Here's how to thin latex paint so it can be used in a spray gun.
Materials you will need:
- 5-gallon (18.9-liter) bucket
Here's what you do:
- Pour the paint into the bucket.
- Add ½ cup (118 milliliters) of water for every gallon of paint.
- Mix thoroughly.
- Check the thickness by running the paint through a funnel. If it flows freely through the funnel, you know the paint is thinned enough. If the paint is too thick, add an additional ⅛ cup of water (30 milliliters) per gallon (3.8 liters) of water and mix.
Remember, adding water will change the color of the paint and alter the drying time. The water also will necessitate using more coats of paint to achieve the desired finish [source: Sherber].
If you want to get a smooth finish, you may want to spend a little extra money and rent an airless paint sprayer, which doesn’t require you to thin the paint to a precise consistency. Be sure to wear a respirator mask and cover anything around you that might get paint droplets on it [source: Stimpson].