How to clean an HVLP spray gun??

I've been spraying quite a bit of epoxy primer, and I had thought that spraying lacquer thinner or acetone between uses would suffice to keep it clean inside. That was wrong. The epoxy paint did build up inside the passages of the gun, despite spraying lacquer thinner each time after I used it, until it quit spraying completely. I took it all apart, scraped out all the built-up paint and got it working again, but it was time-consuming and tedious, and I would like to avoid having to do that again. I guess I'm just not clear on how you are supposed to clean the gun after spraying paint like this. Would it have made any difference if I had sprayed reducer instead of lacquer thinner between uses? Or do I need to disassemble the gun completely to clean it after every use? I'd appreciate suggestions of any easy-ish ways to clean an HVLP gun. Thanks.