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Materials for Homemades FAQ

Last updated on 2008-02-06


Can I use regular party balloons to make a CPS bladder?

Regular party balloons like the ones used in K-modding can be used to make a spherical CPS bladder. They would need to replaced occasionally and do not seal as easily in large numbers. Balloons are easier to achieve extremely high pressure, however.

Does anyone use ABS pipe for homemades?

PVC is prevalent in homemades because of its availability. Guns made of copper, steel, and ABS pipe are still possible, just not made because PVC is cheap and available.

How can I solvent weld or PVC cement?

To solvent weld or PVC cement, you need both PVC cement and PVC primer. Always follow the instructions on the cans as they can differ. If you want a guide with photos, read this page.

Go in a large, clean, open room or area, like a patio or garage with the door open. Make sure there is adequate ventilation. Lay out newspaper to provide a large, clean area.

First, apply primer to the ends of the pipe and the insides of all parts. Apply it to all surfaces that will touch. Applying primer is an important step: the pipes joint much better with it. Forgetting about primer leads to the project's failure in many cases.

After applying the primer, wait until it is dry to the touch. Apply the cement then in the same manner as the primer: on every area that will touch. However, apply cement to a piece and then to the next piece to that it will connect, as the cement becomes solid quickly. Join the two pieces together and twist then to ensure that the cement permeates all touching surfaces. Press and hold the pieces together for at least 10 seconds. Repeat until the project is joined and finished.

Lastly, wait at least 24 full hours until the parts cure.They can't take pressure during this period. Place the project in a dry, clean area (can be the same place as before) that is at least 50 degrees Fahrenheit. After 24 hours, enjoy the success of your project.

How much does PVC cost?

PVC is very cheap. For prices, visit local home improvement or hardware stores or check online websites like McMaster-Carr.

How much pressure can latex rubber tubing take?

Most of the latex rubber tubing on McMaster-Carr operates at 35 psig. This should not alarm builders, however, because CPS operates on the expansion of the rubber, not pressure. If higher pressure water is pumped in, the pressure will be reduced to the rated pressure. Higher pressures can be created through layering of tubes.

How should I glue my PVC cannon together?

Use PVC cement and primer. See the previous question "How can I solvent weld or PVC cement?" for instructions on how to do this.

What is cellular-core pipe? What is the difference between schedule 40 and schedule 80 pipe?

Cellular-core pipe is pipe with tiny air bubbles in it. These bubbles reduce the weight of the pipe, and the amount of pressure it can take. Cellular-core pipe is used in non-pressurized applications. Cellular-core pipe is similar to drainage pipe. Drainage pipe is about an eighth of an inch thick and extremely light. It can take no pressure as well. In water gunning, both are great for reservoirs, containers, and structure.

Schedules describe the amount of pressure pressure rated pipes can take. Schedule 40 pipe takes "lower pressures;" schedule 80 takes "higher pressures."

What is the difference between brass and plastic ball valves?

Brass ball valves are easier to open, stronger, and are only available in threaded sizes. They are more expensive. They can also be modified to accept torque arms other than their originals.

Plastic ball valves are harder to open but are much cheaper. Torque arms can be added to allow them to open more easily.

What is the difference between swing check valves and spring check valves?

Spring check valves always close not matter what position they are in. A spring closes on. Swing check valves rely on gravity to close them, which makes them only work in certain positions. In most applications, spring check valves should be used.

Where can I buy a schrader valve?

Schrader valves are available in most hardware or home improvement stores (Lowes, Home Depot) and online at websites like McMaster-Carr. They may also be available in bike shops.

Where can I buy check valves?

Most hardware and home improvement stores (Lowes, Home Depot) offer them in the plumbing department.

Where can I buy PVC and PVC parts?

In the United States, Canada, New Zealand, and Australia, PVC is readily available at most hardware and home improvement stores. In the UK and Europe, it is fairly hard to come by. McMaster-Carr and the UK Spudgun Supplies Sites are available. If all else fails, copper pipe is available, albeit in much smaller sizes.

Where can I find CPS/elastic/latex rubber tubing?

McMaster-Carr sells it under latex rubber tubing.

Would bicycle inner tube work well for a CPS bladder?

It will work to a certain extent, but it does not expand enough to be very useful. Use latex rubber tubing instead.


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