Monday, November 17, 2014

Spray Gun Instructions

A paint sprayer makes quick work of your project.


If you do any painting, chances are that you'll have the opportunity to use a sprayer. Whether it's a hand-held airless spray gun, a large airless sprayer or an air gun, sprayers make quick work of painting and are sometimes the only tool for the job. Although the inner mechanisms of air and airless sprayers are different, and you use them to spray different materials, there are simple techniques that will work for both types of sprayers.


Instructions


Airless Sprayers


1. Fill the cup of a hand-held paint sprayer about two-thirds full of paint; you can use any kind of oil- or water-based house paint in an airless sprayer. For larger jobs, fill a 5-gallon bucket about half full of paint. Straddle an airless pump over the bucket, with the intake hose immersed in the paint. Connect the pump to an airless gun with a high-pressure hose.


2. Choose a tip for the gun based on the kind of paint you are using. For most latex and alkyd paints and primers, House Painting Info recommends a tip with an aperture between 0.015 and 0.019 inches. Use a wider tip for need heavier materials. For stains and varnishes, use a tip between 0.011 and 0.013 inches.


3. Plug in the sprayer. Test the spray pattern on a piece of old wood or cardboard. Start at one edge of the cardboard or wood, pull the trigger, and move the gun steadily across the face of the material to the other edge. Adjust the distance of the tip from the surface and the speed of movement until you get a solid area of color in the middle of the pattern, without drips.


4. Spray the surface you want to paint in the same steady motion, keeping the gun pointed directly at the surface at all times. If you are painting a large, flat surface, move the gun back and forth from one edge to the other, overlapping about half the width of the spray pattern with each pass. When you have finished spraying in one direction, spray again in the perpendicular direction to cover up any streaks.


5. Empty the gun, or remove the intake hose from the paint bucket. Spray water or another appropriate solvent through the gun to clean the insides. Unplug the gun, remove the tip and clean it with a rag dipped in water or solvent.


Air Sprayers


6. Fill the cup of an air sprayer about two-thirds full of finishing material. Air sprayers give the best results with fast-drying materials, such as lacquer and urethane. Thin the material to the amount specified on the container with an appropriate solvent.


7. Screw the cup onto the gun. Plug the gun into an air compressor and plug the compressor into a wall outlet. Spray a test surface to adjust the fan width. Adjust the width by tightening or loosening the nozzle and by regulating the air pressure. The ideal fan width will leave a full wet coat from a distance of about six to 10 inches with minimal overspray.


8. Spray the surface you want to paint in the same way you would with an airless sprayer, but be sure the surface is wet and shiny after you have sprayed it. If it is grainy, you may be holding the gun too far away or moving too quickly, or the solvent may be too volatile and may be evaporating before the paint hits the surface. Adjust your spraying technique accordingly or change the solvent.


9. Move the gun farther back or move it more quickly if the paint drips or sags. Dripping and separation also can be caused by the presence of silicone or wax on the surface. Dripping also may be a sign that you added too much solvent to the mixture.


10. Let the finish coat dry, then sand it lightly with fine wet/dry sandpaper. Materials that you spray with an air gun usually have to be built up with several coats. Spray the surface again after you have sanded it, then let it dry. Repeat the process as many times as needed to get a satisfactory finish.


11. Empty the material out of the cup when you are finished spraying. Fill it about half full with solvent. Spray the solvent through the gun, then unscrew the cup, remove the tip and drop it in the solvent. Leave it there for 30 minutes or until you are ready to spray again.