Do I Need to Use Thinner When Painting With a Sprayer?

Compressed Air Sprayer

• If you have an air compressor, you might consider getting a paint spray tip, which has a reservoir attached for paint storage. Mixing air into the the paint spray, air sprayers have the most overspray. They can't handle thick paint, so thinning is often necessary.

High Volume/Low Pressure

• A high volume/low pressure, or HVLP, sprayer is often favored for interior projects because it creates a smooth finish with little overspray. Because of its low pressure, it cannot handle thick paints and thinner is needed.

Diaphragm Pump

• Diaphragm pumps find favor because they are easy to use and paint large areas quickly. Thinning is not required. They produce so much overspray that less than half the paint ends up on the surface. Because of the overspray, diaphragm pump sprayers are recommended mostly for exterior projects such as siding and decking.

Piston Pump

• A piston pump sprayer is the fastest, most powerful and most expensive sprayer. A favorite of professionals, it sprays thick paints without thinning. Costing $1,000 or more, a piston pump sprayer can be rented for less than $100 a day. It is suitable for large projects, exterior or interior, as long as precautions are taken to cover nearby surfaces.

Thinners

• Choosing a thinner is quite simple. Latex paints are usually thinned with water, while oil paints are thinned with mineral spirits, or paint thinner. The amount of dilution varies, with guidance being found on paint can instructions. A typical dilution rate is 8 ounces of thinner per gallon of paint.