In finishing you can feed material into a
spray gun via gravity, suction, or pressure. Each method of material delivery
has various benefits and drawbacks, in this post we will cover those benefits
and drawbacks.
Gravity fed guns offer the ideal for
portability as they only have one hose connection for air, while pressure fed
guns have a hose for air and fluid. Gravity guns are also simpler to clean up
due to having a cup that holds only 2 quarts vs a pressure tank that holds a
larger amount of material. In most situations users choose a gravity gun for
touch up work or if they will be primarily spraying thin material in smaller
quantities.
The best way to think of the methods of
delivery is to break down what matters most to you as a user. For example if
control of material and atomization air is your primary control, pressure fed
spray guns are going to provide the best control. More specifically pressure
fed guns that utilize a pressure tank with dual regulators. A dual regulated
pressure tank gives you precise control over pressure of fluid both to the
material and to the air that breaks the material up (the atomization air). An
additional benefit of pressure guns is that they can spray thicker materials
where gravity and suction spray guns may not effectively move material through
the gun due to the material being to thick. The downside of pressure guns is
they can be more expensive because you typically have to have both a spray gun
and a pressure tank rather than a gravity or suction spray gun that do not have
a pressure tank as a separate expense.
Finally a suction gun often is described as
most comfortable to handle because the fluid component is below the gun and
again there is only one hose connected to the gun. The biggest difference
between a suction gun and a gravity gun is that the suction spray gun is even
more limited in material thickness that it will spray because it depends on the
suction force that is created from air movement to draw material through the
gun while gravity depends on gravity to feed material to the gun. To be best
informed about whether a gravity, suction, or pressure fed spray gun will best
meet your needs it's always best to try out the different kinds of guns.