 | Gary Potts is the owner and operator of Professional Automotive Detailing. Gary was born and raised in Wichita where he graduated from Butler County Community College with an associate degree in business. He has been in the automotive industry for past 24 years, and has owned his businesses since 1998. If you have any questions call him at (316) 871-1025 or stop by at 3027 S. Broadway; pottsprodetail@yahoo.com |
Automotive Service & Repair
2011-04-01 13:55:00
Ask the vehicle “inside and outside” guy
Question: I have some questions about painting a vehicle. For instance, how does one properly adjust a standard spray gun? Is it ever recommended to strip the paint and use an aerosol spray paint to repaint? Why do body shops need such a high powered compressor when most spray paint guns I’ve seen only require 10 cfm? What about air-brushing designs on a motorcyc? Are your recommendations the same as they are for any other vehicle?
Answer: I thank the folks at The Q&A Times for allowing me to answer your questions. You’ve got several. Let me get started, with assistance from Bob Story, one of the best in vehicle exteriors.
First, in regards to properly adjusting a standard spray gun…I’m assuming it’s a conventional suction feed spray gun. An HVLP is a little different. Set your air pressure first. The gauge at the gun should read approximately 55 lbs with the trigger pulled far enough to allow air and not fluid. Point the gun at a piece of masking paper, and pull the trigger a bit further to allow fluid. The pattern should be convex, with slightly more paint in the center than the edges. The idea is with a 1/2 overlap, to evenly distribute the material.
Next, in regards to stripping and using an aerosol spray paint…I would not recommend this, unless you’re practicing on an old junk car for some reason.
Next, in regards to the compressor size...you need to think about theory and practice. It’s like apples and oranges. Does a compressor really put out its rated delivery, and does a paint gun really require only 10cfm? Or does it meet VOC requirements if you spray at 10cfm? As Bob Story puts it, “I’ve been spraying paint for a long time, more than twenty years, so I suppose I’m just asking you to take my word for it.”
Finally, in regards to air-brushing…you will find that most professional body painters use an acrylic enamel (uncatalyzed and reduced to a very thin viscosity) for air brush work. It might be a good idea to get your base color finished with a urethane clear coat so you have a nice base to work with. After you are happy with your design, clear over the acrylic enamel with the same urethane clear. It sort of goes against the rules, since uncatalyzed acrylic enamel should wrinkle when clear is applied over it, but maybe because it is so thin it doesn’t, or it doesn’t for most. Lacquers dry too quickly and plug up on the tip of the air brush, and catalyzed paint cannot be stored. Acrylic enamels are cheap, and you’ll only need a few basic (bright) colors to tint with blue, red, yellow, black and white to give you all the colors. One last thing, don’t buy tinting colors, buy mixed colors. The tinting colors don’t have driers added and may not work properly.
