Set up a fire dept scba air tank years ago and only problem is it can only hold air, which won't compress, so can't hold anywhere near as much as a nitrogen tank, since nitrogen compresses under pressure and turns to liquid, if IRC?
Fittings on air tank won't allow you to fill with nitrogen either.
Still better than a sharp stick in the eye when you need to air up something.
Nitrogen compressing into a liquid? You are confusing that with CO2.
Anyway, back to the SCUBA vs. CO2 bottle...
Each has advantages and drawbacks. Which one is right is up to you.
CO2 +
A little more compact
Well known in the comunity
Fairly easy to get filled or exchanged at welding shops, fire extinguisher shops, beverage companies.
In a pinch you can use it with your MIG welder if you run out of gas.
CO2 -
Liquid/gas phase means the cylinder should be used in an upright configuration to prevent liquid going through the regulator. This can cause unstable outlet pressures if liqued is going through a gas regulator not designed to handle it.
It is an axphiant, release contents and you can depleat yourself of oxygen. Some people are not comfortable with having one in a closed cabin of a vehicle.
Cost per fill is generally higher. I figure I will generally drop $10-15 per fill depending on the shop, the day, the counter person, etc.
Exchanged tanks are often heavy steel.
Owned aluminum tanks have the added cost of Hydro testing every 5 years.
Hard to know the amount of gas remaining, pressure is not accurate, have to weigh the tank and know the empty weight as well.
Scuba +
For you, you already have the tank.
Amount of gas remaining is easy to determine via simple pressure gauge
Fill cost is generally less. Last check around $4
Also useful for paintball and Scuba
Will operate in any oriantation
Regulators are easy to find. Old first stage can be had for a few bucks. Splice the rubber hose for standard fittings. Flow is generally very good.
Tanks are generally lighter.
A leak inside an enclosed vehicle will not deprive you of oxygen.
Scuba -
Generally less use per fill. A common aluminum 80 tank holds somewhere around 5 pounds of air, so a comparison is half of a 10Lb CO2 bottle and 30% larger as well.
Almost always owned tanks so there is a hydro every 5 years (as opposed to swapping tanks for a current hydro at a CO2 dealer, but same if you own a CO2 tank and have it filled which is common for aluminum CO2 tanks)
There are other local things that may affect the viability as well. In a small town CO2 fills are generally easier to find. Larger cities the SCUBA may be easier to deal with in a retail enviroment (later business hours for easy after work drop off and pickup).
Years ago I ran a SCUBA tank. old steel 72 that only held 2250 PSI. Also happen to have a friend who owned a dive shop. I would go in, piddle around, do a vew visuals and fill some tanks for him, toss mine in for a free fill. So that worked great for me. Then I won a CO2 bottle in a raffle. I switched to that, but I found the benifits of the CO2 never outweighed what the cost would have been. If I had never won that CO2 bottle, I would still be using SCUBA tanks. Even now that the shop closed and I would be paying for them, I would still use the SCUBA tanks filled with air.
Look around the garage, I have a large collection of tanks. Oxygen, Acetelene, Scuba, weld mix, CO2. Multiples of most. I have wheeled and dealed tanks one way or another. I do see why CO2 is good. But I don't see the reason to get one when you have another option sitting on the shelf that will work nearly the same.
disclaimer; I am sure I missed a hits and misses...
