OK paint gurus, I've been painting a few motorcycle tanks off and on for a while, now im getting more and more people wanting to paint bigger stuff. I've just been using a touchup gun with a 1.0 tip. The small cup has worked fine for small stuff, but not working on bigger things. I've began looking at guns, and dont really understand the difference between primer, paint and clear guns. (well I do, but not the fine nuances) Can someone explain the differences, and reccomend a good all around gun? Not looking for the best there is, but something decent that I can spray all around with? Maybe something that I could swap some tips to make it work as a multipurpose kind of deal?