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Wich gas use?

Posted: Sat Mar 07, 2009 11:25 am
by Demon
I want to make a paintball gun with an compressed gaz bottle to give air power, but what gas use? (they all cost 5 $ for 14 oz)

-Propane

-Mapp

-Oxygen(this one i think)

I dont intend to use propane or mapp because its flamable but is oxygen dangerous? i mean, to breath or just like that for some reason( like attacking metal fittings)

Wich one?

And also, is there enough pressure in these 14 oz bottle to make something of it?

Re: Wich gas use?

Posted: Sat Mar 07, 2009 11:32 am
by ramses
you are best off using propane or mapp. Oxygen has the following problems:
1. it is under extremely high pressure
2. the bottle is left hand threaded (meaning you can't just put it on a propane torch)
3. under pressure, any oil can spontaneously combust

where are you able to get mapp for the same price as propane? I must know.

look at this

Posted: Sat Mar 07, 2009 11:32 am
by brplatz
Oxygen is also flammable. :) But unlikely in a PVC cannon.

It would be better to use CO2 or HPA. More shots per Tank. And its inert.

EDIT: Damn beat... :D ramses, what are you talking about oil for? There is no oil here.

Posted: Sat Mar 07, 2009 11:42 am
by ramses
Oxygen is not flammable. It is an oxidizer, that is to say that it makes other things burn. that is why I brought up about oil. valves require lube, which is normally an oil, which oxygen likes to make burn. that is why they sell special oxygen rated gauges and fittings/valves. normal valves and gauges are lubed with oil, and oxygen rated ones are lubed with something else, maybe silicon oil. whatever, doesn't matter, because he would spend more on an oxygen regulator than a CO2 reg.

Posted: Sat Mar 07, 2009 11:44 am
by Demon
where are you able to get mapp for the same price as propane? I must know.
Maybe not the same, i did'nt checked, but in the same bottle.

Is it really under more pressure then the mapp or propane bottles?How much?

And no i cant use co2 or hpa because they dont sell them under 5 $ and in propane or mapp gaz bottle. I am trying to find cheap solutions here.

Heres what i am talking about:

http://www.homedepot.ca/wcsstore/HomeDe ... nada_4.jpg

Posted: Sat Mar 07, 2009 11:56 am
by john bunsenburner
Well overall HPA and/or CO2 are both cheeper to use than mapp, O2 or propane, it is just sold in larger amounts thus more expensive, try bulk air...

Posted: Sat Mar 07, 2009 11:59 am
by Lentamentalisk
Ok, I have never really understood those bottles. They most def are not storing the oxygen as a liquid, so I doubt they actually have 14.5g of gas in there. I would check the label on that. I doubt you will get more than a single fill for your cannon off that.
Go for propane.

Does anyone know anything about those propane style bottles filled with oxygen?

Posted: Sat Mar 07, 2009 12:01 pm
by ramses
yeah, that should work fine. you might go thought it fairly fast in a larger gun. oxygen bottles hold about 40 liters of gas in 1 liter of volume, or 40 bar or 600 psi (pressure drops with use)

propane maxes out at like 150psi, and you get 218 liters of gas, which stays at a pressure based on this chart.

when you draw propane from the bottle, the bottle and gas get cold, so I recommend a metal expansion chamber, since pvc gets brittle with cold. again, read through this thread.

Posted: Sat Mar 07, 2009 12:03 pm
by Lentamentalisk
john bunsenburner wrote:Well overall HPA and/or CO2 are both cheeper to use than mapp, O2 or propane, it is just sold in larger amounts thus more expensive, try bulk air...
Wrong. Propane can be bought for about $1/lb if you buy the 20lb tanks. Good luck finding a place that will sell you CO2 for $1/lb.
Mapp and O2 on the other hand, since mapp is no longer being produced, will keep raising in price, and O2 is just a PITA to deal with, and not stored as a liquid, so it will tend to cost more.

Posted: Sat Mar 07, 2009 12:07 pm
by ramses
MAPP isn't produced anymore? that sucks!

Posted: Sat Mar 07, 2009 12:07 pm
by john bunsenburner
ok if you consider, pressure, volume and efficiency then air is definately better and i think CO2 is too.

Posted: Sat Mar 07, 2009 12:10 pm
by Demon
Does anyone know anything about those propane style bottles filled with oxygen?
YES! i know.

They are selling some in my rona in red bottles. So if i understand, its definitly too dangerous to use oxygen???

Posted: Sat Mar 07, 2009 12:20 pm
by Lentamentalisk
Demon wrote:They are selling some in my rona in red bottles. So if i understand, its definitly too dangerous to use oxygen???
Yes, I have seen those. Either it is safe to use, because they are storing it at a very low pressure, so it will empty crazy fast, or it is unsafe, because they are storing it at a high pressure.
Use something else.
Propane will be 2-4x cheaper if you buy it in bulk than mapp.

ramses wrote:MAPP isn't produced anymore? that sucks!
It was the biproduct of a petroleum product that is no longer being made, if I remember correctly what I overheard at the welding shop.

@john: dont double post
edit: also, john, no, air is stored as a compressed gas, so propane, mapp, and co2 will all be more space efficient than air.

Posted: Sat Mar 07, 2009 12:27 pm
by john bunsenburner
I didnt double post, and i am still fairly sure plain air is better, oh well

Posted: Sat Mar 07, 2009 12:30 pm
by Demon
If i use propane, wont it be too much dangerous(like burning if a smoker is near)? i just wanna know which is the safest: Propane or Oxygen...