fran said: December 28, 2009 1:22 pm PST
Hey Gui
For me, the issue was the overall pressure of the system, meaning that if the pressure was high, the system worked better than if it was medium or light. I used to use salvaged latex whoopie cushions quite a bit for the pressurized air-bladder, and I found that if I doubled them up, one inside the other, that they were sufficiently robust to provide the higher air-pressure. An added benefit is that when one breaks, the instrument continues to function, but at a reduced volume...
As for the air inlet/water inlet connection where the 3/4,3/4,1/2" cpvc tee meets the sprayer...It might give you a stronger mechanical connection if the stub coming off of the cpvc tee was 1/2" rather than 3/4" (like of you used a 3/4, 1/2, 1/2' cpvc tee). Here's why: often these sprayer things have a conical opening in the handle that the 1/2" pipe jam-fits into nicely...
good luck!