How to use an airless paint sprayer
Airless paint sprayers are a great way to apply a lot of paint in a short amount of time – much faster than using a brush or roller.
You can also get a smooth, flawless finish on tricky things like paneled doors, cabinets or wainscoting. You can apply thin materials such as stain or varnish just as easily as thicker liquids like latex paint.
Airless sprayers pump paint through a hose and out the spray gun tip at very high pressures – up to 3,000 psi. The tip breaks the liquid evenly into a fan-shaped pattern of tiny droplets. This atomization of the paint allows for perfectly smooth finishes with a little practice, but novices can run into trouble the first time they use one, including runs, drips and overlap marks.
And not all of those tiny droplets of paint will stick to the surface. Much of the atomized paint lingers in the air, and if you don’t know what you’re doing, you can waste 40 percent or more of your paint.
Preparing the area
As with any type of paints and primers, before you begin, all surfaces need to be smooth, clean and free of imperfections that could show through the finish. With a paint sprayer, you’ll need to spend more time masking off adjacent surfaces and spreading drop cloths over anything you don’t want to have covered in tiny specks of paint.
If you’re painting inside, you can set up a large fan in an open window or door to draw atomized paint droplets and fumes to the outside. Just make sure those droplets won’t be settling on anything like porches, decks, furniture, shrubs, etc.
Using an airless sprayer outside can be tricky. Don’t use paint sprayers on breezy or windy days, as the droplets can move and settle on trees, windows and even vehicles.
Preparing the sprayer
The first thing you need to do when using an airless sprayer is to prime the pump. There are two tubes in a sprayer: a large suction tube to draw paint directly from the can or bucket, and a smaller prime tube to get the material into the pump.
Place the suction tube in a bucket of strained paint and the prime tube in an empty waste pail. Select “prime” on the sprayer valve and turn it on. When paint starts flowing from the prime tube, you can move it into the paint bucket and let the pump run for about 30 more seconds, or until no bubbles come out of the tube.
Next, hold the gun – with no tip installed yet – over a waste bucket. Pull the trigger and turn the spray valve to “spray.” When a steady stream of paint is flowing from the gun, release the trigger and follow the instruction manual for relieving pressure. You can then install the guard assembly and spray tip. Be sure the arrow on the tip is facing forward, toward the material to be painted.
Never use a worn tip. Tips may have to be replaced after spraying 15 gallons of paint or they can last through 60 gallons, depending on how abrasive the paint is that you use.
The final step is to adjust the pressure. Using a large piece of cardboard or other fairly clean waste material, spray a strip of paint to check the pattern. If the pattern has tails or gaps at the top and bottom of the pattern, the pressure is too low. Adjust the pressure until the paint is evenly distributed across the fan pattern.
As you spray, the paint sprayer tip wears and enlarges. Starting with a tip hole size smaller than the maximum will allow you to spray within the rated flow capacity of the sprayer.
Painting with an airless paint sprayer
Always keep the tip of the paint sprayer parallel to and roughly the same distance from the surface you are painting – usually about 10 inches. Don’t angle the tip up to reach high spots, bring it down parallel to the middle and then angle it down to paint lower on the surface. Always keep the tip moving in a straight line parallel to the surface, not in an arc or angle.
Squeeze the trigger before you get to the surface you want painted, and move the sprayer fairly quickly across it (keeping it parallel). Release the trigger just past the point where you want the paint to stop. For example, if you are painting a door, begin by aiming the gun about 8 inches to the left of one edge.
Then, as you move the tip toward the leading edge of the door, press the trigger so paint starts spraying before you actually reach the door. Keep a straight, parallel line all the way across the door and release the trigger just after you get past the opposite side.
Overlap the next pass about 30 percent, again making sure the gun tip is perpendicular to the surface and you move it parallel across the entire surface. Move fast to prevent drips and runs – several thin coats are better than one thick one.
Fan width is the size of the spray pattern you put down and it determines the area you will cover with each stroke. Select the fan width that is best suited to the surface you are spraying. Wider fans deliver a thinner coat and provide better coverage on broad, open surfaces. A narrower fan delivers a thicker coat and provides better control on small confined surfaces.
Plan your spraying sequence before you start. For example, if you are spraying doors, spray the edges first, then spray top to bottom, and then spray at right angles side to side. This will ensure even and complete coverage with minimal chance of lap marks or drips.
Most spray problems are the result of clogged filters, clogged tips, or a pump that is leaking or has stuck ball-check valves. If paint sputters or stops, you may have a clogged tip. Most tips are reversible, meaning you can twist it in the guard 180 degrees until the arrow is pointing at you. Then you can spray into a waste bucket or against a piece of scrap to clear the clog, rotate it back and begin spraying again.
Use paint hose that’s at least 25-feet long and wrench tighten it, using two wrenches. Every time you spray, check the hose for damage. Don’t try to repair the hose if the hose jacket or fittings are damaged. Replace it.
Always work in a well-ventilated area, and wear safety glasses and an approved mask or respirator. Gloves and hearing protection is also recommended.
Follow safe procedures when painting. Never point the spray gun at another person or at any part of your body. Do not put your hand over the spray tip. Do not stop or deflect leaks using your hand, body, glove or a rag. Keep the trigger locked when you aren’t spraying. This not only prevents accidental spraying, but it helps prevent injuries.
The high-pressure fluid from a gun, hose leak, or ruptured components will pierce skin. While it may look like just a cut, it is a serious injury that can result in severe health problems, including amputation. Get immediate medical treatment.
When spraying flammable oil-based products, follow all grounding precautions to prevent sparks. All pertinent safety information will be included in the paint sprayer manufacturer’s instruction manual.