- You will need a propane torch to apply heat to the pipe. This makes the pipe extremely hot. Do not touch it until it cools. Cooling can take several minutes.
- Use no more than 5 to 10 milliliters of water.
- The metal ball, along with the steam jet pushing on it, exits the barrel with substantial velocity. Clear the area in front of the cannon of people, animals, and breakable objects for 100 yards, or use an acceptable shooting backdrop.
- Never, ever look down the barrel of the cannon.
- Wear safety glasses and heat-resistant gloves.
- Handle the propane torch safely. Read and follow the propane torch manufacturer's instructions.
- This project is not intended for children. For use by adults or under close adult supervision.
- Your experience may differ from ours. Accidents happen, and things can and do go wrong. Therefore, tackle this project at your own risk.
- 10-inch-long 3/8-inch diameter pipe nipple
- 4-inch-long 3/8-inch diameter pipe nipple
- 3/8-inch diameter pipe elbow
- Ball valve with 3/8-inch NPT openings
- Pipe reducer, 3/8-Inch Male NPT to 1/4-Inch female NPT
- 2-inch-long 1/4-inch diameter pipe nipple
- ¼-inch pipe tee
- Pressure gauge, ¼ inch NPT connection
- Pressure relief valve, 1/4-inch NPT connection
- Pipe sealing compound
- Metal-jawed vise
- Safety glasses
- Heat-resistant gloves
- Propane Torch
- A quantity of 7/16-inch steel balls. Steel balls can be ordered online from places such as McMaster-Carr or Amazon.
- Pipe wrenches
Connect the pipe fittings and valve together as shown in the assembly drawing. It is very important that all fittings are screwed together tightly with no leaks. Poorly connected joints will leak hot steam and cause poor performance.
Find a safe, suitable area for testing your steam cannon.
Securely clamp the cannon in a vise. Angle the barrel at least 15 degrees from the horizontal, but not more than 45 degrees.
Open the ball valve. Pour in 5 to 10 milliliters of water, making sure it reaches the reservoir section behind the valve.
Don safety glasses and heat-resistant gloves.
Close the ball valve. Use the propane torch to apply heat to the reservoir portion of the cannon. As you heat, watch the pressure gauge while looking carefully for leaks around the joints. If leaks are present, wait for the device to cool before fixing the joint. Stop heating when the pressure gauge reads 20 PSI. Do not exceed 20 PSI.
If no leaks are present, test-fire the cannon by quickly opening the ball valve. Then load it up with steel balls and follow steps 4 through 6 to fire at a target. WARNING: Follow the safety instructions, and fire the cannon at your own risk!