Expert: Gary - 5/20/2008

Question
I painted the hood of my car using a PPG one step paint. I mixed it in the ratios recommended by the supplier. I have very bad "orange peal" to the finish. What typically causes that?

Answer
Hi Craig,

Several things could cause it.

1) Spray-Gun Setup
    PPG typically recommends a 1.4 to 1.6 mm tip size for most single stage finishes.   
2) Poor choice of reducer
    I usually recommend 1 step slower reducer for overall paint jobs over the normal recommendation for the air temperature.
3) Painter Technique
     Distance from the panel is the biggest mistake most painters make. With newer HVLP model guns you need to be 8-10 inches from the panel.
4) Temperature and Humidity
     Warmer temperature and higher humidity can drastically change re-coat times and solvent and hardener selections.
5) Insufficient Air Supply
     The newer spray-guns need more of a volume of air than pressure. Many people think that since their compressor puts out 120 psi they can attach a spray-gun and start painting. However that's not always true. The rule of thumb for air is if while you are painting the compressor runs over 50 of the time then it's to small.
6) Poor quality Spray-Gun
     Not all spray-guns spray the same. Spray-guns are all about quality. Not all countries build spray-guns under the same specifications. If you opt out for a cheap spray-gun expect to fight it trying to get a good finish.

You might also check out this article I wrote a while back: http://www.repaintsupply.com/sgtroubguide.cfm

I hope this helps you out.