Portable Oxygen ....Steel or Aluminum tank?

[Mooney13]

I am looking at portable oxygen systems and I am wondering if there is anything besides shape and weight that I should consider with steel vs. aluminum systems?

I see the shape is a bit different and the regulator is placed on the side of the steel tanks vs. on top with aluminum....

Anything else I am missing?

 

Thank you for any advice

[KSMooniac]

I went with an aluminum Precise Flight 22 cu. ft. system and am happy with the capacity and especially the weight.  I try not to carry any extra weight as a general rule...

[Piloto]

Go with the aluminum. It less prone to internal corrosion and lighter in weight. I have a 15 cu-ft that is compact enough to be placed in between the rear seats with Velcro strips. The valve is forward so it is easy for me to open and close it. I pay $18 at a Scuba dive shop for oxygen fill up.

José

 

[Jerry 5TJ]

Many steel O2 tanks can be recertified every 5 years indefinitely, at a test cost of $20 (current 2009 prices).  Some lighter-weight steel tanks, and composite tanks have service life limits. 

In the USA, the DOT regulates these tanks:

Type 3AA 1800 steel cylinders must be tested every five years.  They have indefinite service life provided they pass inspection criteria.

Type 3HT 1800 steel cylinders must be tested every three years, and they have a service life limit of 24 years, after which they must be destroyed.

Type 3AL seamless aluminum cylinders require test every 5 years and generally have a 15-year service life.

Composite cylinders (often Aluminum with Kevlar wrap) must be tested every three years and have a 15-year service life, after which they must be destroyed.

Another point on O2 costs -- most shops charge a flat rate to fill your tank, be it large or small.   So I have a big one, oxygen tank that is, and that makes my O2 at least twice as cheap per hour as the smaller tanks more commonly seen in portable systems.

[Piloto]

Go with the aluminum. It is lighter and less prone to corrosion. The only time steel tanks make sense is for Scuba diving. Steel tanks do not need weights like the aluminum tanks when on water.

José

 

[Jerry 5TJ]

If you really want to save weight, buy a composite tank.  They are super in volume-to-weight ratio.   But they cost a lot; like a nice bicycle, you pay for the weight you don’t have to carry.

Those old, low-tech 3AA series steel tanks are cheap.   I have one with a 1960s manufacturing date.   It has been hydro tested any number of times, most recently last week.  It holds 50 cu feet and cost me $5 at a pilot swap meet plus a hydro test.  Yes, it weighs 32 pounds, but it will give 40+ man-hours with an oxymizer at 12K feet.  

Cost to fill is $40 at the airport -- so that's $1.00 per hour.   I go on O2 at 9000’ day and 5000’ at night.

Yes, you can get your O2 bottle filled at the scuba or welding shop, but make sure they put in O2 and not air or Nitrox.   No, that's not a joke -- I recall an accident report where the NTSB found the O2 bottle contained 21% oxygen, to wit, compressed air.    Reference NTSB IAD97FA060.