I don't have part numbers for the paintball components, because I ordered these from a local paintball pro-shop. They retailed the parts and put together custom tanks with anti-siphon tubes and on-off valves. I recommend this "in-person" approach, because the pro was able to describe the tank-filling process and suggest possible solutions to various engineering problems.

Breadboard pneumatic setup

1. Catalina Cylinders 20 oz. aluminum CO2 cylinder
2. Shocker regulator (see regulator closeup)
3. Safety Lockout Valve
4. McMaster part 6124K152, Solenoid & Air Operated Directional Valve, Single Solenoid, 5 PORT/2 Position, 3/8", 24 Vdc
5. 24 volt switched power source for solenoid valve
6. 3" bore 6" Bimba reservoir with 3/8" NPT ports, used for expansion tank
7. "War Machine" surplus 3" bore 6" double acting pneumatic cylinder, 3/8" NPT ports

Note the coating of frost on the 20 oz. tank (1) after testing. At room temperature, liquid over gas CO2 will be between 800 and 900 psi. The regulator cuts that down to 150 psi. We get about 10 shots at full pressure, and 9 more shots at partial pressure.

CO2 filling station

1. 50 pound "dip" tank of CO2
2. chain to hold tank upright securely
3. Main shut-off valve
4. Fill valve
5. Bleed valve (with plastic tube attached to discharge to carry away exhaust)
6. Tank fitting with depression valve
7. Paintball tank with on-off valve
8. Digital scale with Tare function

Regulator closeup

1. CO2 tank
2. On-off valve and anti-siphon fitting factory installed on tank (note black mark showing the up position for the anti-siphon tube).
3. Shocker regulator, with 1/8" NPT output ports.
4. Steel tubing between regulator and expansion tank, tubing is McMaster part 89895K24 (Type 304 Stainless Steel Seamless Tubing, .12"ID X 1/4"OD X .065"WALL), fittings are McMaster part 52215K139 (Bite-Seal Compression Steel Tube Fitting, Male Adapter, 1/4" Tube Od, 1/8" Pipe Size).

 

Updated for TI-2 Safety Rules

This larger photo shows the final setup after installation in the robot, and updated for the BattleBots Tech Regs V1.0 as used for TI-2, Season 4.0. Note that the pneumatic valve was upgraded from a 3/8" port to a 1/2" port valve, increasing the flow rate from 1.6 to 5.0 Cv, and making the weapon much faster. Also note that the cylinder used in the final version was a smaller McMaster 2.5" x 4" stroke cylinder, giving about 14 full pressure shots with the weapon (out and back counts as one activation), and another 5-10 weaker shots.

1. Paintball tank, 20oz (with anti-siphon tube installed by Paintball supplier)
2. Burst disk mounted on paintball tank
3. Shut-off valve mounted on paintball tank
4. (new) Pressure gauge on high pressure side (0-1500 psi, McMaster part 40565K18)
5. Shocker regulator, adjusted to 150 psi
6. Low pressure gauge (0-300 psi, Small Parts, came with regulator)
7. (new) ASME pop-off valve (175 psi, McMaster part 48435K716)
8. Bimba 3" diameter resevoir 6" length
9. Purge valve
10. Solenoid operated directional valve, 5 port 2-position (McMaster part 6124K56)
11. (underneath, not labelled) 2.5" bore 4" stroke pneumatic cylinder (McMaster part 6491K264)

This setup passed safety, once we demonstrated that the nylon tube fittings (McMaster part 5016K466. 5016K699, and 5016K144) were rated for 220 psi.