Expert: William Forster - 6/24/2007

Question
Hello William,
    I tried to spray paint my car yesterday using Standox paint and a $20. HVLP spray gun bought from a going out of business sale. The coating is similar to an orange peel and after three coats of two part clear coat there is no shine.
    What went wrong?

Thanks,
John Weiss

Answer
Probably just about everything that could. What sort of air filtration set up do you have for the compressed air? Oil and water from a compressor will contaminate air, and make paint look like hell. Was the gun rated with a spray tip rated to spray clear? It should have a number very close to 7.0 on the fluid tip. All guns are not created equal, lower number than 7.0 are usually base coat guns. Numbers much higher are usually primer guns. Base or primer guns won't shoot clear well, especially an overall. How high was the humidity? What sort of clear was it? Some clears are fast clears, only rated to do a panel or 2. Others are overall clears- they dry MUCH slower. What temperature was the hardener rated for spraying at? Was the temp within those parameters? What sort of air flow did you have in the spray area? Too little flow, and the overspray in the air comes back down, and lands on the car. What air pressure were you using this gun at? HVLP's don't require a lot of pressure, like a siphon feed DeVilbiss JGA gun spraying acrylic enamel.