TargetTalk

Where I live scuba companies are far and few between, but a friend of my acquired some decommissioned medical aluminum oxygen tanks and is offering them to me. They are smaller and seem more portable (essential for taking them to our practices). The only question is would they work? I'm not sure why they were taken out of circuit, they were provided by a medical supply company and perhaps they have to be specially inspected due to their use or circulated out after so many years?

I'd appreciate any thoughts on the subject, as free is better than new as long as it doesn't wreck our pcp rifles!

I am pretty sure it will not have the correct fittings. Generally oxygen is filled to 2200 psi, so that is pretty low.
I bit the bullet and have a 4500 psi SCBA cylinder. That is the best cylinder for your application.

Absolutely not. Oxygen can burn just about anything.

You might look for nitrogen. It would be much cheaper, too.

I think (hope) the OP was just referring to using the cylinders for air. But no, they'll have the wrong fittings. And you don't want to put Oxygen through an air gun. Things burn that don't usually burn, and at lower temperatures when you increase the O2 content from 21% to 100%.

Sorry for confusion, wasn't planning on running oxygen, they are just old aluminum medical oxygen tanks. Sounds like though they might not be pressure rated high enough, so if I cant get above 3K probably not worth it.

Talk with your local Welding supply store they deal with all sorts of gasses

COBelties wrote:Sorry for confusion, wasn't planning on running oxygen, they are just old aluminum medical oxygen tanks. Sounds like though they might not be pressure rated high enough, so if I cant get above 3K probably not worth it.

To prevent filling tanks with the wrong gas, i.e., oxygen in an air tank, the fittings are generally gas specific.

There are plenty of places you can buy a scuba tank online and I have heard that local fire departments will usually fill them for you if you have no other options and are using them for junior programs and such.

I was wondering the same thing about decomissioned oxygen tanks. If purged and you had say 6 tanks hooked together in series and all 6 could hold 3000 psi., wouldn't it work as a fill station then? They basically have the same type of valve as a scuba tank and if hooked together in series you could regulate the pressure between the tanks to make the right pressure to fill your pcp gun tank right? I'm not sure about it just wondering if it could be done. Any experts on this?

Use this to calculate how many times you can fil based on each tank https://www.airgunsofarizona.com/Tanks/FillCalc.html

The anschutz is 200cc. Now you can compare how many times you can fill from the 3k tanks, 3442psi tanks or the 4500 psi tanks. Then compare costs as well. I'm thinking of getting a high pressure steel at 133 cubit feet, about half the price of the SCBA tanks, does about 2/3 of the number of fills of the SCBA as well but will weigh more.

A new scba is about 45$ per year for 15 years, use that as a baseline when trying to "save" money on other tanks

"Basically the same type of valve as a scuba tank" is very different than exactly the same == will work without expensive adapters. It's very easy to spend a lot of money on fittings in order to save a few bucks on the tank.

But in regard to your question about hooking several up in series, don't bother. Yes, that will give you more volume (but not more PRESSURE), but there's no reason to deal with a bunch of tanks hooked together -- just use one until the pressure drops too low to be useful, then move on to the next full one.

marky-d

Oh, and good luck getting someone to fill your oxygen bottles with air -- unless you can fill them yourself, you are probably out of luck.

i am constantly suprised at the lengths some g to just to try to save a couple bucks by seriously overcomplicating things. All new pcp guns come with the adapter fitting to hook to the appropriayely rated tank for failsafe filling. Some say the 4500 psi tanks are best.... thats their opinion. A 4500 psi tank will not fill any FWB PCP guns fail safe. You run the risk of overfilling them. All I had to do to fill my P44 or 800x was to crack the valve and let the tanks equalize. I bought a 200 bar tank and was done. easy peasy.

Possible future Darwin Award......

Check fitting spec. they are very different.

▌▌DIN 477 (German Institute for Standardisation - Deutsches Institut für Normung)
DIN 477 PART 5 2002 INLET CONNECTION CONNECTOR TYPE CONNECTOR DESCRIPTION GAS PROPERTIES

D9 DIN 477-1 No. 9 G 3/4" Oxidizer Oxygen
10 DIN 477-1 No. 10 W 24.32 x 1/14" RH Inert Nitrogen
D11 DIN 477-1 No 11 G 3/8" Oxidizer Nitrous oxide (>3 l size)
D12 DIN 477-1 No. 12 G 3/4" INT Oxidizer Nitrous oxide (<3 l size)
D13 DIN 477-1 No. 13 G 5/8" INT Non-flammable Air
D14 DIN 477-1 No. 14 M 19 x 1.5 LH Various Mixtures
D54 DIN 477-5 No. 54 W 30 x 2 (Ø15.9/20.1) Non-flammable, non-toxic and non-oxidizing gases and gas mixtures
D55 DIN 477-5 No. 55 W 30 x 2 (Ø15.2/20.8) Non-flammable, toxic and corrosive gases and gas mixtures
D56 DIN 477-5 No. 56 W 30 x 2 (Ø16.6/19.4) Pressurized air

David M wrote: ↑Mon Feb 14, 2022 4:33 am Possible future Darwin Award......

How 'bout acetylene?