Features and working of a gravity feed spray gun

The gravity feed spray gun is often powered through compressed air. The body of the tool is linked to air tanks in which pressurized air is stored. When the lever is depressed, the pressurized air is released and provides the force to propel the contents of the spray gun through the nozzle. The air consumed is around 15 cubic feet per minute (CFM) to generate a force of approximately 29 pounds per Square inch (PSI). The tool is designed for a steady spray of the liquid with very fine atomization. A metallic particle control feature ensures uniform output. The gun uses the force of gravity to ensure smooth spray with minimal air consumption.

A diaphragm regulator enables the user to control the volume as well the speed of the water spray. A two speed trigger feature offers the user added speed adjustment control. Most gravity feed spray guns incorporate the High Volume Low Pressure (HVLP) system, whereby the volume of the air is increased and the pressure is decreased simultaneously to improve the spray efficiency and also increase the coverage. A forged aluminum body provides the tool with a strong and durable casing. Frequently, the spray gun has an approximately 600cc to 1 liter aluminum or PVC container for the paint and other fluids. This container normally has a funnel/strainer holding ring to ease refilling of the relevant liquid.

The pressure and aim of the spray is enhanced with a variable speed fan, which can be controlled by the user depending on the intended application. The fan also incorporates a ‘round to flat’ adjustment. An intrinsic micrometer gauge enables minute measurements of the air volume. The spray gun, which uses an approximate 1/4 inch air inlet, offers a big fan pattern with negligible overspray. The air inlet as well as the fluid outlet can be adjusted. The spray pattern can be modified with a knob provided at the side of some spray guns.

Inline gravity feed filters separate dust particles from the paint to provide a cleaner flow. Subsidiary filters also extract oil vapors, moisture, and rust.

What to look for in a gravity feed spray gun

A stainless steel needle and tip prevents rust formation and increase the lifespan of the product and makes it usable for water based liquids. Durability is further enhanced with solvent resistant Teflon seals and jeweled nickel plating. A hands-free spray gun holder with pre-drilled holes allows the tool to be attached to the wall or a bench. The handle of the gun is ergonomically contoured to increase the comfort Level of the user and also to prevent wrist strain during prolonged use.

The spray gun is designed to enable thorough cleaning without removing the micrometer and other air gauges. Thus the settings of the gun are maintained. The inlet pressure is constantly monitored during use to ensure consistent flow. Considering the pressure at which the tool works, the safety factor for the user cannot be ignored. All spray guns need to pass international safety standards.  The air cap is designed for quick removal and refitting. Often spray guns have a digital pressure management feature for added accuracy. Some reputed manufacturers of gravity feed spray guns include Astro Pneumatic, Campbell Hausfeld, DeVilbiss, Porter Cable, SATA, Sharpe, TD Industrial, and Titan.