now that you have the paint chamber complete we can now build the air chamber.
Step 1: Pressuizing cap
Take one of the galvanized end caps and drill a hole to fit the tire valve. Put valve in. I suggest to seal everything from hear out with gasket sealant including the tire valve.
take other end cap and drill a 7/16" hole and tap with the 1/4"-18 pipe tap.
Clean, seal and tightly screw together the end caps with the 2" galvanized pipe. This will be the air chamber.
Take the 3/8" ball valve and screw in both 3/8"to1/4" adapters. On the opened side of the lever, file a small square notch into it for the trigger tooth to set in and drill a small hole to put the spring to. The farther out the hole is the better! the valve is in the closed position in the pic, the air tank will be at the bottom of the pic.
When the valve is open you want the lever of the valve to point to the air tank, the longer 1/4" nipple goes between the tank and the valve. VERY IMPORTANT!! With the valve in the OPEN position, screw in the long 1/4" nipple into the side that the lever is pointing.
On the opposite side of the valve, screw in a short 1/4" nipple then the bottom hole of the 1/4" T to that nipple(make sure flat part of the T is parallel with valve lever), then screw in the other short 1/4" nipple into the side of the T that is on the same side the lever is on when the valve is closed. The last hole will get the 1/4" plug(this is how you fill the paint). This is the air plumbing.