For larger painting jobs, an airless sprayer is the most efficient way to apply paint. An airless sprayer uses an electrically run hydraulic pump to move paint from a bucket or container, through a tube, into a high-pressure hose, to a spray gun, and, finally, to the surface. Once you get the knack of it, an airless sprayer is easy to use, but if you rent one, make sure you get a set of written instructions.
The instructions will tell you how to flush the system with solvent (usually water or mineral spirits, depending on the paint you'll be using) and how to pump the paint through the hose to the spray gun. For cleanup, the procedure is reversed: Pump the leftover paint out and flush with solvent.
You'll only need the spray rig for a day or two, but plan to spend at least another day beforehand to thoroughly mask off everything you don't want to paint. Tape drop cloths to every floor surface. Drape windows, the fireplace, and doors. Remove all hardware or cover it with masking tape. Mask switches and outlets. Paint from a sprayer travels on the tiniest of air currents and settles a fine mist of overspray on just about every surface in a room.
Plan to keep at least one window in each room open and set up an exhaust fan to draw paint vapor out of the room. Be sure, too, to wear a painters' mask, a hat, and old clothes with long sleeves to protect your arms.
Airless sprayers are equipped with several filters to keep paint particles and foreign matter from clogging the spray tip, but it's a good idea to filter the paint yourself through a nylon stocking or paint filter before you pump the paint through the hose.
Effective Airless Sprayer Use
Using an airless sprayer effectively takes some getting used to, so plan to practice on some scrap plywood or an inconspicuous part of the room or the house. The object is to cover the surface with a uniform coating of paint. Hold the spray gun a constant 6 to 12 inches from the surface and maintain this distance with each pass of the gun. Keep the gun precisely parallel to the wall. Don't sweep it back and forth or you'll end up with a wide arc of paint on the wall; the paint will be concentrated in the middle of the arc and almost transparent at each end.
Paint about a 3-foot horizontal strip at one time, then release the trigger and drop down to paint another strip of the same length, overlapping the first strip by one-third to one-half. Once you've covered a 3-foot-wide area from the top of the wall to the bottom, go back to the top and start another 3-foot section adjacent to the first, overlapping the edge of the first painted area by several inches as you work your way down the wall again.
Examine the painted areas to make sure the entire surface is receiving a uniform coat of paint. Too much will run or drip; too little will let the old paint show through. If you notice these flaws, it means you are not keeping the spray gun a uniform distance from the wall at all times or that you are tilting it. An upward tilt will deliver excess paint to the bottom of the painted strip. A downward tilt will concentrate paint at the top of the strip.
To prevent paint buildup at the end of each strip, release the trigger on the gun a fraction of a second before the spray gun stops moving at the end of your stroke. When beginning a new strip, start moving the gun a fraction of a second before compressing the trigger. Always keep the gun moving when it's spraying.
Be sure, too, that you've properly thinned the paint and adjusted the pressure control according to the manufacturer's instructions. If there is too much or too little thinner or too high or too low a pressure, the spray of paint won't atomize properly.
Using an Airless Sprayer Safely
Airless sprayers are fast and efficient because they supply pressures of up to 3,000 pounds per square inch. This force moves the paint at 100 to 200 miles an hour through the spray tip. All that power can be dangerous. Consequently, treat an airless sprayer with lots of respect, follow the manufacturer's instructions to the letter. Use the following precautions to prevent accident or injury:
- Keep the spray gun's safety lock on when you're not painting.
- Make sure the spray gun has a trigger guard and a safety shield around its tip.
- If the spray tip becomes clogged, do not try to clear it by pressing your finger on it while the paint is being sprayed. Keep your fingers away from the tip when the sprayer is operating.
- Never point the gun at anyone else or allow anyone to point it at you.
- Always turn the sprayer off and disconnect it from its electrical source before you clean out the gun or the sprayer's filters. Even then, if you have to clean the tip, squeeze the trigger to release any built-up pressure in the hose.
- Only work in a well-ventilated area, wear a painters' mask to avoid inhaling fumes, and don't smoke or work around open flames. If you're working outside, don't leave containers of solvents sitting in the hot sun; put them in the garage or another shady spot.
- Never leave the sprayer within reach of children or pets.