Some help before.....

[psycix]

C:B ratio doesnt matter much on a pneumatic.
Examples

If you choose a 1:1 or something around that its fine, if you choose 1.5:1 its fine if you chose 0.8:1 its fine, if you choose 2:1 its fine or whatever it doesnt matter that much.
Its more like: how much do you want to pump for the blast.
Smaller chambers just get pumped up faster. (DUH!)
But larger chambers will yield a bit more power. (with diminishing returns as you are getting larger!)


About your 40$ budget:
It depends on your design and what you want.
Rough estimations:
-A few small pieces of pvc will cost not much more then 15$ .
-Ball valve: 10$ or so?
-Glue/primer: 10$
Total: 35$
Maybe something is more expensive, so add 5$.
Makes 40$

[Mr. Beaver]

About your 40$ budget:
It depends on your design and what you want.
Rough estimations:
-A few small pieces of pvc will cost not much more then 15$ .
-Ball valve: 10$ or so?
-Glue/primer: 10$
Total: 35$
Maybe something is more expensive, so add 5$.
Makes 40$

ty you just made me a bit happier

[psycix]

ty you just made me a bit happier

Good! Now get going and build that cannon!

I suggest you to go to your hardware store and check out all prices of all parts and check if they have everything you need for your design.
Sometimes some parts are not available in the area where you live and you will have to change design and improvise to solve that.
The price calculation I gave you was very rough, it could be way less OR way more, so you should check that asap.

Good luck!

[Mr. Beaver]

The price calculation I gave you was very rough, it could be way less OR way more, so you should check that asap

yeah i tought so, but you know it's more or less but also the problem here that is i need to know what i need befor i go cause i talked about it with leav is a user here from israel also and i know where to get the pressure rated PVC pipes but even knowing that is not enough cause when i'll go buy the stuff it's my dad driving me to the place with the pipes and stuff then i'll need to go to a bike shop for the schrader valve and my father count on me on that it wasn't that easy to convince him about all of this......

[mega_swordman]

Since no one really answered your question about the barrel support, I feel that it is my patriotic duty to answer it (cue flying American flags and jets flying overhead).
I think the best idea is to take a T-joint the same diameter as your barrel, file down the pipe stops, and then you can slide the t-joint onto your barrel. Then all you need to do is connect that to the elbow like you described in your diagram.

[SpudUke5]

Sometimes

Hence the reason i used sometimes

[DYI]

When people ask for C:B ratios on pneumatics, one can assume that the chamber size is fixed, since adding chamber volume always increases performance. Since adding more barrel volume can increase performance after 1:1, the information was inaccurate.

[Mr. Beaver]

ty but i'm done with the C:B ratio it's not complicated after you got it the first time .....