Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 56 users online :: 4 registered, 0 hidden and 52 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Wich gas use?

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Unread postAuthor: Lentamentalisk » Sat Mar 07, 2009 12:33 pm

oops sry, I misthought sry sry sry.

Yes, air may be "better" but that is qualitative and unspecific. First of all, it is not one of the 3 choices we were offered. Second, it may be cheaper, if you have a scuba or paintball shop around, but it also requires a heavy high pressure tank, or a $200 carbon fiber tank, if you want to store a reasonable amount of gas. Also, you need a paintball or scuba shop, which it seems like our man here doesn't have, seeing as how he wants to use gases from the hardware store. Last but not least, CO2 and HPA both require an expensive regulator, because they run at such high pressures, unlike propane, which runs at 50-180psi depending on temp.

In some cases it is better though. For example, anything stored as a liquid, though more dense, will vary pressure dramatically with temperature, and will begin to freeze if you use it too quickly, because the gas needs to boil off.
  • 0

Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Unread postAuthor: Demon » Sat Mar 07, 2009 12:35 pm

By air you mean oxygen?
  • 0

User avatar
Demon
Colonel
Colonel
 
Posts: 743
Joined: Sun Apr 13, 2008 8:46 am
Reputation: 0

Unread postAuthor: Lentamentalisk » Sat Mar 07, 2009 12:39 pm

by air, i mean HPA. Oxygen is something entirely different. the air we breathe is only 21% oxygen

Oxygen is not one of your options. It either will have next to no air in it at all, or will cause something to detonate in your face.

As for the fire hazard of propane, it depends on what your conditions are. If you are playing outside, then you are fine. Even the slightest breeze will blow it all away. I would not use it inside though.
  • 0

Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Unread postAuthor: john bunsenburner » Sat Mar 07, 2009 12:40 pm

No by air we mean air 20%oxygen 79%nitrogen and 1%argon(some other gasses are also in this mixture)
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: Demon » Sat Mar 07, 2009 12:52 pm

There is a refuelling port on the side of the bottle, is it an standard one so i can refill in paintball stations or an special fitting one?I mean by special that its hard to get.

What psi can handle the cylinders?
  • 0

User avatar
Demon
Colonel
Colonel
 
Posts: 743
Joined: Sun Apr 13, 2008 8:46 am
Reputation: 0

Unread postAuthor: john bunsenburner » Sat Mar 07, 2009 12:54 pm

Which cylinders?
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: roboman » Sat Mar 07, 2009 1:40 pm

@John: I'm guessing he's asking about HPA/CO2 cylinders. And yes, if you use a paintball tank, they have a standard fitting for refills.

If I were you, I wouldn't use mapp or propane in a pneumatic. They smell really bad, and if you plan to use bottles from the hardware store it can get really expensive. HPA or CO2 are your best options here. At Harbor Freight, they sell a cheap CO2 regulator for ~$45. Also, you can get CO2 for that at Lowes or Home Depot.
  • 0

User avatar
roboman
Sergeant Major
Sergeant Major
 
Posts: 176
Joined: Tue Nov 25, 2008 11:18 pm
Location: Long Beach, CA
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: ramses » Sat Mar 07, 2009 1:52 pm

hpa tanks can take up to 4500psi, but the pressure drops with use CO2 pressure varies with temperature, and the pressure doesn't necessarily drop with use. CO2 tanks get cold with use, and should be used with a metal expansion chamber, as coldness makes pvc brittle.
  • 0

POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
User avatar
ramses
Major General
Major General
 
Posts: 1679
Joined: Thu May 29, 2008 6:50 pm
Reputation: 3

Unread postAuthor: john bunsenburner » Sat Mar 07, 2009 2:43 pm

HPA pressure varies with pressure too of coarse, but not quiete as much. And you cannot control the pressure you get from tank refills for HPA and CO2, so i was not sure if that was the cylinder ment :D
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: Lentamentalisk » Sat Mar 07, 2009 2:48 pm

practically, HPA doesn't vary with pressure. A drop in temperature from room temp to freezing will decrease the pressure by ~7%, where as with propane, going from room temp to freezing is at least a 50% drop in pressure. Besides, if you are using HPA not regulated down to more practical pressures, then you have much bigger problems to worry about than temperature changes.


Back on topic, your best choices are either propane, or splurge and go for a nice CO2 setup.
  • 0

Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Previous

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot]

Reputation System ©'