CO2 tank?

[Delphinus]

Last cylinder I picked up was from the Recharge Centre over by Blackfoot Inn. They sometimes have used cylinders (mostly converted fire extinguishers I think). Kari suggested this place and I checked into it and that's where I get my cylinders refilled now. Anyhow I got a nice bright red 10lb steel cylinder from them.

There are two types of CO2 cylinders, aluminium and steel. Steel tends to be cheaper. Supposedly what happens is that aluminium cylinders use an O-ring type seal on their valves whereas steel cylinders use a tapered thread tapping. So everytime the cylinder needs to have its hydrostat retested (every 5 years, if not current you will not be able to get it filled), on a steel tank the valve will grind into the cylinder just a little wee bit more than the time previous. This means after about 4 or 5 tests the tank is done (doner than done). However at 5 year intervals that means a tank will last you at least 20 years anyhow and frankly at $80 or whatever for the tank, I think I'm OK with that (Your mileage may vary!) I guess it's a more important consideration in terms of how many times the tank has been hydrostat'd before you come to own it yourself.

Hydrostat testing usually costs around $50 I think. Anyplace that fills them will be able to do this for you if you need it done.