I have a Fuji XPC spray gun. I've read they are notorious for leaking at the cap. Mine has lived up to that reputation. When I'm spraying WB finishes, I wet the gasket with water and that does the trick.
I've been spraying lacquer lately and I've just been trying to tighten the cap best I can. Sometimes it works, sometimes it doesn't. It leaked badly today and I started wondering if I could use spray gun oil on the gasket? If not, does anyone have any idea what I could use to create a better seal?