New cannon question

sully4 · Tue Aug 12, 2008 1:49 pm

I am looking to build my first air cannon and was hoping for help. I am Looking for something of smaller size but i can not pick a cannon. One of my choices is the Mini Paintball Launcher at Free Paintball Plans, It is the small size that is nice, but it is almost too small. And I would have to buy the 12 gram change and 12 grams...Have any of you built that?

My next pick would be a cannon that has the chamber under the barrel and a sprinkler valve. But I Don't know all what I need for that. If I could get some help, It would be great. Could I have the barrel and the chanber both 2", and could i fill it with a bike pump easily?

Oh and I would like to use it for backyard paintball and spud launching.

Thanks,
Sully

daberno123 · Tue Aug 12, 2008 2:08 pm

Sure Sully, you could easily build a cannon that meets your expectations. However, if you come looking for step by step plans, here isn't the place. Look around through the Pneumatic Showcase section for some more ideas and to get some more specific questions.

But for the ones you have already asked...

1.Yes you can have both the chamber and barrel 2"

2. As long as the keep the chamber length under 2', a bike pump would be feasible.

sully4 · Tue Aug 12, 2008 2:13 pm

Thanks for the Help Daberno,
No I was not looking for step by step. Just some help.
And would it just be easier to have the chamber bigger than 2" Dia? And would I be able to fill the chamber if it is lets say 3" dia? I will have to do the volume math..
Sully

daberno123 · Tue Aug 12, 2008 2:25 pm

It really just depends on how long you want to have to pump before firing. There is nothing wrong with a 3" diameter chamber, but keep in mind it will take longer to pump up.

For paintball you'll want a minimal amount of time between shots, so a small chamber and and a long barrel (more efficient) will probably be your best bet.

Another thing to keep in mind if you decide to use a 3" chamber is that Nsf-pw fittings are harder to find, most notably bushings. Most likely your local Home Depot or Lowes won't carry them, and instead will carry DWV bell reducers that ARE NOT rated for pressure. This shouldn't be a problem if you have a plumbing supply store near you though.

Oh and I almost forgot, welcome to Spudfiles!

sully4 · Tue Aug 12, 2008 2:31 pm

Seeing as you put it that way I might stay with the 2" PVC I have. I do not have a plumbing store anywere near by to my knowing. Are bushings the flat reducers? I think I used one on my potato cannon. If so then I have a place to buy it.

Thanks for all the help. I was hoping for help like this.

p.s: I have been playing with that GGDT thing. It is helpful and I will be checking out my options.

daberno123 · Tue Aug 12, 2008 2:52 pm

This is the bushing I was talking about.

Don't use one like this.

A read through this page should answer all your questions about PVC fittings.

I'm glad to see you utilizing GGDT. I seldom design a gun without consulting it first.

sully4 · Tue Aug 12, 2008 2:55 pm

Thanks for the help man, After messing with GGDT i think I will go with the 2". ANd posibly make the Mini paintball launcher if I have some extra time/chash

daberno123 · Tue Aug 12, 2008 3:05 pm

Sounds like a good plan.

Make sure you post it when you finish it!

sully4 · Tue Aug 12, 2008 3:10 pm

One more thing I just read about:
Will I be able to fill the chamber fast enough to close the valve? If i have a 2ft long 2" pipe?