Home > Parts > Pat's TECH TIPS BLOG > My Chamber Broke on the Lock Tab (or Piston Were the Chamber Locks on)

Try decreasing your air supply down to 80psi.

Many run at 120 Increasing the line pressure increases the force thinking they get a better fan pattern.Truth is, the air supply does 2 things.1: purge air supply to the front of the gun. For purge air you need volume, not pressure.

Graco assembly #49 is 1/4" air hose. SPF Depot part #15B772 assembly #49 is 3/8" and that will give a higher volume of air if you want it.2: the air supply shifts the piston when you pull the trigger. This is were you will understand air pressure -vs- shifting force.The piston 2 diameter.

Pi times the radius squared. So 3.14 (pi) x 1(radius of a 2" piston) x your inlet pressure.3.14 x 80psi =251.20 pounds of shifting force.

3.14 x 100psi=314.00 pounds of shifting force.3.14 x 120psi is 376.8 pounds of shifting force.

As you can see, the shifting force is like a hammer on your parts. The shifting speed is not effected. With that amount of force, it is easy to see why OEM chambers will break.

Turn your pressure to 80psi. You will not see any difference in the speed and the fan pattern has nothing to do with the air pressure, that's controlled by system pressure - 1100-2000psiAt 120psi, most of you could sit on the gun, pull the trigger and the gun will shift (if you weigh under 300lbs)