I have two gravity fed airbrushes (where the paint cup feeds from the top) and another siphon airbrush (that feeds from the bottom) and I've never had the problem you describe. I'm wondering if you're not cleaning yours after using them (no criticism intended) and if investing money in some off-the-wall, with no name other than Lifetime Guarantee, side feed is worth it. Once again, I'm not being critical, just analytical.