Joined: October 01, 2010
|Turbine Time - 9
Posted: Sun Aug 12, 2018 5:29 am Views: 24
Rating: Not rated
|When I attach the gun directly to the turbine outlet (no hose), I get a solid 6psi flow pressure through the air pressure fitting. This isn't the perfect place to catch pressure but at least it's inside the gun. 6psi is about the max you'll get out of this gun with a single turbine because the 7500/7700 is a conversion gun (needs 22psi to get 10 at the cap).
With a 50 foot hose, 6-stage turbine, Apollo 7700 gun (everything adjusted wide open), and 1mm needle/B cap, I have fully adjustable flow pressure from .5-5psi at the air pressure fitting. Hopefully the cap pressure is in the same range or higher. The difference between high and low speeds hovers around 2psi.
The pressure increases when I adjust the overspray control below its recommended setting and also when I narrow the fan. At the smallest fan setting and trimming the air, I can get 9 psi in the gun. I might make a cap pressure gauge to see what's going on up front but a lot can be inferred from the chart for compressed air use.
If you want to shoot this gun to its full potential, there's no such thing as having "more stages than you need". At 2psi per stage, you'll "need" an 11-stage turbine to shoot get a 10psi cap pressure.
About turbine unit pressures - retail turbines market their maximum pressure as a "sealed pressure". Sealed pressure is taken off the capped end of the motor with no hose or gun. You might get half that when you add the required parts to actually spray paint.