According to Coating Equipment Technology, Inc. (Chesterfield, MI), abrasive, two-component, or moisture -curing materials can wreak havoc on a spray gun's wearable parts. Specifically, the needle seal packing, which is the most important wearing part in any spray gun, takes the brunt of the abuse from aggressive media use. With enough wear to these parts, the gun can start leaking and a repair would be needed. Depending on your material, this can be quite frequent and can incur significant costs.
WALTHER PILOT engineered the diaphragm spray gun; also known as a membrane gun. Instead of a needle seal packing (the part seeing the majority of the wear from use of aggressive materials), these specially designed spray guns are equipped with a diaphragm (membrane). The diaphragm ensures that all wetted parts are separated from the air components; this ensures that the spray gun is virtually leak-free. The material needle does not go all the way through the gun. Instead, the spray gun is operated by a pneumatic pulse that relieves the pressure of the rear spring located in the air compartment. This design results in significantly longer service life and ensures that repair costs are kept to an absolute minimum. Designed for spraying the types of problematic materials mentioned above, WALTHER PILOT has several spray gun models that are equipped with diaphragms for virtually any spraying application.