DO-IT-YOURSELF : Spray Paint Coats Exterior Faster Than Flicks of the Wrist
When it comes to painting your home’s exterior, spray painting is at least twice as fast as brushing, and much less fatiguing.
Commercial sprayers may be expensive, but they can be rented for about $75 a day. These units use air to atomize paint to a fine mist by means of an air compressor.
They work like this: Paint follows the air stream out of the tip in a sort of cloud, causing a high percentage of the paint to trail away from the surface being painted. This trail is called overspray.
Airless sprayers, designed for do-it-yourself house painters, cost about $100-$250 and come in two basic designs. In piston-type systems, paint is pumped directly through an atomizing valve at high pressure. The other type, diaphragm pump systems, atomize paint by means of a mechanical screw, and they deliver the paint to the gate valve at relatively low pressure.
Most of the do-it-yourself sprayers have their pumps built into a hand-held unit.
To spray paint, prepare surfaces as you would for brushwork. Trim and siding must be clean and free of unsound paint. All bare spots must be primed, and fixtures and hardware not to be painted must be removed or masked.
You can remove aluminum storm doors and windows, but consider that factory-finished metal surfaces make an excellent base for spraying latex. So if you want them to match the color of your siding, by all means paint them. Just make certain they are clean.
To begin, first prime the pump by spraying onto paper or another uncritical surface. If the pump won’t prime, the paint probably has to be thinned.
Start the sprayer with the nozzle pointing away from the work surface, then move it into position about 12 inches away. Work with rhythmic strokes, keeping the sprayer upright and parallel to the plane of the wall. Don’t go over previously painted areas until they are dry.
Work from the top down, spraying a thin even coat. Several thin coats produce a better finish than one thick one. If drips, runs or sags occur, remove excess paint with a brush.
Remove all masking when the paint is dry to the touch. Inspect the job and finish with a brush any areas where the masking blocked the spray. If your trim is to be a different color from the siding, paint the trim first using a hand-held shield of cardboard or thin hardboard to protect the siding from the spray.
As far as maintenance is concerned, the single most important practice for airless sprayers is to keep them clean. If you work directly from the paint container with a long siphon tube, tape the tube to the container rim to keep it off the ground. Flush the tube thoroughly with solvent if it does contact a foreign substance.
When you are finished for the day, spray solvent through the gun for several minutes. Then disassemble the unit and soak the non-electrical parts in solvent.
Wipe all the built-up paint from both the cap and cup and reassemble the unit and put a drop of light oil in the suction hole. Switch the unit on for a couple of seconds to circulate the oil.