I just did it a few weeks ago. Had my gun too far away when clearing the engine bay and it wound up rougher than hell. Thought I'd wet sand it and apply another coat or two and call it good. Nope. Then went to dry. Went all the way down to 60 grit and that wasn't even doing it so I had to get out the power tools and start all over lol
Another note, I was using that HF gun to spray epoxy and it always came out rough no matter what I did so I switched to my Eastwood gun and it flows much smoother. Either I don't know what I'm doing or HF guns are really hit and miss depending on their quality control. You see some guys online doing beautiful jobs with them but I could never get it down.