My HVLP spray gun came equipped with a standard metal fluid-pickup tube. It works fine until I tip my gun to get inside a cabinet. Then the gun sputters and spits because the pickup tube is no longer in the finish. I mentioned this problem to a buddy who flies remote-control model airplanes. He provided me with the perfect solution. It’s called a clunk, as in clunker. It’s a metal nozzle that model airplane hobbyists attach to the end of the fuel line in their airplanes. It keeps the fuel line in the fuel when they perform acrobatic flying. I bought the large 1/4-in version at a hobby store for $2. I cut off the spray gun’s original metal pickup tube and replaced it with a piece of 1/4-in. plastic tubing and the clunk. This modification won’t make my gun fly, but at least it keeps the pickup tube in the finish no matter what angle I tip the gun.