Soda bottle or PVC?

elad311 · Mon Oct 13, 2008 3:47 am

I want to build my 1st pneumatic and I don't know what to use as
a chamber:
1.75L Soda bottle, Or 2" 1 foot long PVC
I don't know how much psi they can take!

burke_a_lot · Mon Oct 13, 2008 3:58 am

I would go with the PVC to be safe....

littlebro05 · Mon Oct 13, 2008 5:32 am

Actually PVC is more dangerous than a soda bottle.

Soda bottle = Burst and rupture = fright
PVC Tank = Burst and shatter = injuries

Make sure you don't use PVC DWV and find out if it's pressure rated. Oh btw a soda bottle can generally hold up to 160PSI or 11bars... but to be safe I'd operate on it on 100PSI because soda bottles aren't pressure rated, it's just that I've heard from people it can go up to 160PSI but not recommended to use it at that level of pressure

.

elad311 · Mon Oct 13, 2008 7:01 am

I want to use a plastic soda bottle, but I don't know if mine is
good, I can squeeze it, Can I use it? Or I need another kind of soda bottle:

littlebro05 · Mon Oct 13, 2008 7:07 am

If that's a coca cola bottle 1.25L then you're in luck. I've actually tested it when I was making portable pre charged air tanks for my BBMG's and don't worry it should be able to handle up to 100PSI with no problem. You can go higher if you want but 100PSI is probably the most safe bet since they're not pressure rated, shouldn't try to go any higher... but I will, you can if you want and report back.

And yes don't worry mine was squishy too and it could handle the pressure. Worse case scenario bottle breaks, you probs drop your nuts in surprised but not injuries will sustain... but where glasses JUST incase. Every precaution counts you know.

elad311 · Mon Oct 13, 2008 7:16 am

Actually, I'm using a 1.75L plastic one, Do you thing it can went up
to 110-120 psi with no problem?

O, and, Can you give me a link to a video or a picture that shows
how connect the bottle to the valve with no leaks?

littlebro05 · Mon Oct 13, 2008 7:21 am

elad311 wrote:Actually, I'm using a 1.75L plastic one, Do you thing it can went up
to 110-120 psi with no problem?

O, and, Can you give me a link to a video or a picture that shows
how connect the bottle to the valve with no leaks?

Umm 1.75L should be fine too 110-120PSI should be fine and if it blows up cost like 2 bucks to replace anyway + excuse to drink coca cola <,<.

Well this is how I connect my valve, but IF you're making a pneumatic launcher I have no experience with it... This design is strictly for me for BBMG's.

Take a look at some of pneumatic cannons that uses soda bottles that might help you.

http://www.youtube.com/user/littlebro05

take a look at my BBMG prototypes.

Ragnarok · Mon Oct 13, 2008 7:29 am

I would recommend the PVC, as it's much less likely to fail, and also looks more professional. Cannons with drinks bottles tend to look like they've been built out of what you've found in your dustbin.

Seriously, don't use plastic bottles, they might be safer IF they fail, but they're far more likely to go in the first place.

elad311 · Mon Oct 13, 2008 7:45 am

Well, I still don't know what to use, I think, or to use
the 1.75L plastic bottle, or to use a 40cm 1" PVC PIPE (as a chamber)

And, should I use 3/4" valve and barrel, Or 1/2" valve and barrel?

Ragnarok · Mon Oct 13, 2008 7:59 am

My own suggestion would be the PVC chamber and the 3/4" valve/barrel (because I like barrels of about that bore).
Alternatively, you could get excellent results from the 3/4" valve with the 1/2" barrel, which should produce decent velocities.

Ultimately, your barrel choice should be based on the ammo you can get your hands on. Although you would do well to remember that smaller things can fit in larger barrels if you put some wadding behind them.

elad311 · Mon Oct 13, 2008 8:29 am

Ragnarok wrote:My own suggestion would be the PVC chamber and the 3/4" valve/barrel (because I like barrels of about that bore).
Alternatively, you could get excellent results from the 3/4" valve with the 1/2" barrel, which should produce decent velocities.

Ultimately, your barrel choice should be based on the ammo you can get your hands on. Although you would do well to remember that smaller things can fit in larger barrels if you put some wadding behind them.

Well, I have an awesome ammo for this: a 1/2" metal ball,
But what do you mean 1/2" barrel with 3/4" valve?
Can't that make an explosion?

A pic of the ball:

Ragnarok · Mon Oct 13, 2008 8:35 am

elad311 wrote:Can't that make an explosion?

No, not at all. Many cannons have a larger valve diameter than their barrel diameter, which provides a higher air flow to the barrel, and thus more performance.

Indeed, my cannon HEAL has a barrel with a 20.3mm bore, but the valve is 22.1mm across internally, which helps promote it's performance - it's not blown up yet.

elad311 · Mon Oct 13, 2008 8:52 am

Ragnarok wrote:yet.

yet? what do you mean yet?!
I can explode after some shots?

And, about the chamber, I don't care if it doesn't look professional,
I just want it more powerful, so, Bottle can reach about 100 psi,
how much the 1" 1 foot long PVC can take?

Ragnarok · Mon Oct 13, 2008 9:03 am

elad311 wrote:yet? what do you mean yet?!

Exactly what it says. I am not expecting it's failure, but I cannot say with 100% certainty it will never fail (but that is because you can't say that for anything), thus, I qualified it with an addition that confirmed I was only speaking for time passed so far.

In other words, it has been used so far without any problems. I cannot speak for the future, but things should be fine.
The valve configuration is in no way related to the likelihood of if it's failure.

And, about the chamber, I don't care if it doesn't look professional,
I just want it more powerful, so, Bottle can reach about 100 psi,
how much the 1" 1 foot long PVC can take?

I wouldn't recommend using the bottle at 100 psi, probably 80 psi at maximum.

However, the PVC should be capable of taking around 150 psi.

elad311 · Mon Oct 13, 2008 9:10 am

Ragnarok wrote:However, the PVC should be capable of taking around 150 psi.

But, normally, PVC explodes at 100 psi... right?