I think hes confused at what *hypertek* said about HVLP gun spray it. Witch stands for High Valume Low Pressure, that is required to have an air compressor. You can get a much more durable clear coat and finish after using one but if you cant find one your only choice is to use spray clear..
I got my gun from devilbiss and it is an HVLP but i have a 60 gal compressor to push it because i personally use it for painting the whole body.. but if you have a compressor and wanna get one youll probably have enough pressure to last for a bumper.
This is what i got.. great gun and great quality.
http://www.tcpglobal.com/spraygundep...-lgcup700h.jpg
DeVILBISS - FinishLine Master Kit
i dislike the blue i got a chrome one. but yeah its a good gun.. cost effective.