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Posted: Tue Dec 18, 2007 7:39 pm
by ShowNoMercy
Jesus Christ almighty, if your using a system that is not plumbed directly into your cannon, aka using a schrader valve, then watch your gauge and relax. I have my reg plumbed directly into my cannon and I just use the on/off on the tank to fill the chamber, and good golly I still have all body parts and still 20/15 vision. Go figure.

Posted: Tue Dec 18, 2007 8:00 pm
by EGOed
Well , you dont know the specifics of the cannon he is designing or how much experience he has using compressed gases , so it is better to explain the safest way to do this .........Anyone who posts on this forum should know that this is what Spudfiles is all about.....You may be comfortable putting CO2 into a PVC chamber with no safety pop off , but I have seen paintball regs and guages fail , more than once with CO2 and HPA.....You can check out my website , www.highenergypaintball.com as I own this paintball field and have seen a lot of inexperienced people do dangerous and stupid things with compressed gases.

Posted: Tue Dec 18, 2007 8:04 pm
by DYI
IN CORRECT!

The Problem with CO2 is in the liquid state, if something causes a no siphon tank to get past horizontal the liquid WILL Freeze your REG in an open state and allow the CO2 liquid to expand into a gas causing a massive Rise in pressure. This will cause a catastrophic explosion and send PVC schrapnel a couple of hundred feet.

I know someone who nearly lost their life in an accident described just above. He cause a 3 inch chunk to the neck, slicing him from collar bone to ear, and missing his jugular by milimeters.


Co2 + PVC = MmmmBad K??
INCORRECT (not in correct) Your statement assumes that proper safety measures are not followed. It is often dangerous to make assumptions, one way or the other in this hobby.

I obviously didn't word my response correctly. PVC is reasonably safe to use with CO2 if the proper safety precautions are taken. These include a relief valve of some sort on the pressure vessel, as well as keeping the tank upright, and not being a complete idiot.

It is a violation of building codes in almost all of North America to use PVC piping for ANY compressed gas system, so the entire idea of making a pneumatic from PVC is shaky at best to begin with. Unfortunately, some people insist on using PVC anyway. In this case, as long as the proper (and rather numerous) precautions are taken, it is no more dangerous than using PVC with most other inert, compressed gases.

Whether a gauge or regulator fails or not, a well set burst disk relief valve of any decent diameter will be enough to avoid a chamber explosion.

Posted: Tue Dec 18, 2007 8:10 pm
by Novacastrian
Deleted wrong thread. :oops:

Posted: Tue Dec 18, 2007 8:14 pm
by DYI
I was just about to point that out when you deleted the post...

Posted: Tue Dec 18, 2007 8:18 pm
by EGOed
Thank you DYI as this is the only correct answer I have seen so far in this post........Anyone who says a safety pop off valve on a PVC chamber is totaly unnessesary , is definitely not building the safest launcher possible and probably shouldnt be giving advice on safety of CO2 and PVC.

Posted: Tue Dec 18, 2007 8:28 pm
by Erlex
Wow, very mixed answerers. I guess ill just take it from you guys. Ill just use a smaller HPA paint ball tank I own. But, this whole ordeal with cold PVC being brittle, sounds like a fun experiment because it seems as to one is sure. I am definitely going to test that. Should be fun. :D

Posted: Tue Dec 18, 2007 8:31 pm
by ShowNoMercy
Dont take the argument above the wrong way, C02 is completely safe if used the right way. A pop off valve set at a good pressure, keeping the C02 tank level and of course using proper regulators. And if your smart about things and respect how much force is contained in that C02 tank then you should be fine.

Posted: Sat Dec 22, 2007 12:58 pm
by Zippster
I remember reading something about CO2 being safer if you charge an expansion chamber which you then fill your cannon with. Is this completely irrelevant? You'd think it would help to evaporate any liquid that may make its way in and make the shots more consistent/etc., but again would this do any good?

Posted: Sat Dec 22, 2007 1:18 pm
by bigbob12345
I dont see how it would

Posted: Sat Dec 22, 2007 1:28 pm
by frankrede
BigGrib wrote:Man I don't even know what to say to all of this.
The Problem with CO2 is in the liquid state, if something causes a no siphon tank to get past horizontal the liquid WILL Freeze your REG in an open state and allow the CO2 liquid to expand into a gas causing a massive Rise in pressure. This will cause a catastrophic explosion and send PVC schrapnel a couple of hundred feet.
Ummm What?? CO2 evaporates off inside the tank and if liquid went up through the regulator if you were that big of an idiot to turn your tank on it's side while filling your chamber (i travel with mine on the side with the main valve off and the regulator attached) and get a slug of liquid through the regulator you might freeze your regulator but you're not gonna blow the whole thing up in a huge catastrophic failure.

It happened to turbohackers father.
A catastrophic explosion due to regulator failure.

Posted: Sat Dec 22, 2007 1:51 pm
by Brian the brain
Regulator failure...not regulator freezing..


THere is nothing but CO2 in there, so what exactly is FREEZING ???

As far as I know, only water "freezes"..

Or do you mean the temperature drop is so radical..the fluid CO2 turns SOLID and crystalises... :shock:

I don't think so buddy!!
Get a decent regulator and keep the bottle upright, it should be fine. 8)

Pressure is potentially dangerous (that is the very reason we use it!!) so make sure your equipment is in order..( stop checking your pants!! That's not what I mean!!)

Posted: Sat Dec 22, 2007 3:18 pm
by socoj2
The temprature drop causes the Spring to Freeze open..

You guys are posting on a forum where 90% of people who build their first cannon dont know any better and use Non Pressure rated DWV.

ACIDENTS HAPPEN why take chances.


Image

This was the after math of someone nocking over a C02 bottle and causes the cannon to blow up. This would have causes a pressure increase to about 900 PSI in 2" pipe. But in reality it probably only made it to about 500 PSI before blowing.

C02 under pressure is a liquid, When it is released from a pressure state it causes a temprature drop liquid C02 is VERY cold *reason number 2 not to use C02 with PVC*

Posted: Sat Dec 22, 2007 4:19 pm
by goathunter
Yep,Socoj2.I remember that blow up.Your guy got off lucky on that one.To tell you the truth I'm half suprised that Brain and Skeeter hadn't set up a ban on launchers yet.I had a freak nerf from my team's JCS(I hate that thing) nail Brain's oldest son in the gut.Partially the kids fault,he unfortunately learned the hard way why you don't stand a foot off the back corner of a tank.

To everyone else:
I for one can tell you that I've run cannons off of Co2 for years and have yet to have any problem.If you do your homework and take care of your equipment there is no reason to get hurt.And people, you won't hear me stress it enough.If your building a low pressure system,pop off valves are a must.In fact all but 1 field I've gone to has required a pop off on cannons.If you don't like one on your gun, mount it after your reg in the backpack.Simple as that,$12 or an appendage.Your choice.

Posted: Sat Dec 22, 2007 4:41 pm
by grumpy
@Brian the brain;
Dry ice is the genericized trademark[1] for solid carbon dioxide. It is commonly used as a versatile cooling agent. Dry ice sublimes, changing directly to a gas at atmospheric pressure. Its sublimation and deposition point is -78.5 °C (-109.3 °F). Its enthalpy of sublimation (ΔHsub) @ -78.5 °C (-109.3 °F) is 199.0 kJ/kg (245.5 BTU/lb). The low temperature and direct sublimation to a gas makes dry ice a very effective coolant, since it is colder than ice and leaves no moisture as it changes state

http://en.wikipedia.org/wiki/Dry_ice

i have had my paintball marker completly ice up and freeze at high rates of fire, took 2 to 3 minutes to thaw out. and co2 can be safe as long as proper safety precautions are followed.