Aviation Oxygen

[drifter1430]

Just trying to get an "Advanced" discussion started...

I was surprised to find out that it all comes from the same manifold and after years of being told that welding gas was bad or dirty, that "we have been told by the suppliers of welding oxygen, the purity level required for welding and cutting purposes is more critical than for breathing".

I don't have a mix station completely set up yet, but through where I work I can get a discount on all kinds of gas (industrial, medical and aviation, not to mention helium.) After paying roughly $55.00 for a fill of 21/35 in a set of double LP85's at a local shop. It's time to get going.

[Vtach]

Its good to see some activity in the advanced discussion forum.

I agree with you that all oxygen probably comes from same bulk area.  I think the bigger issues for me are how the tanks are treated and guaranteed purity.  I have been told by my supplier that industrial tanks are not routinely vacuumed and are not guaranteed for the same purity as breathing gases.
I think in general you are getting a relatively equal purity between grades of oxygen but contamination is more likely to happen to unvacuumed cylinders and the gas companies liability is much higher with breathing gases, hence the guaranteed purity standards.  I guess I don't see a prohibitive financial issue with using ABO versus medical and industrial.  So I go with what will work best for me and gives me peace of mind in knowing I have a generally accepted standard of purity in each breath.

FWIW, I have 3 T's of oxygen and 3 T's of helium.

$16 oxygen.....
$60 helium......
$300 yearly tank lease.....
$400 digital fill whip......
my own personal trimix/deco gas filling station.......PRICELESS

[divbum]

[quote='Drifter1430 link' pid='981' dateline='1134914776']
Just trying to get an \"Advanced\" discussion started...

I was surprised to find out that it all comes from the same manifold and after years of being told that welding gas was bad or dirty, that \"we have been told by the suppliers of welding oxygen, the purity level required for welding and cutting purposes is more critical than for breathing\".
I have sat through 3 lectures on gases and the supply chain (fell a sleep a few time in one) and read specs on gases.  Welding grade can be as low as 97% or 98% pure.  All manufactures have a minmum spec for there gases at each grade.  If you are looking into setting up a fill station ask for this sheet on ABO and industrial and even USP from your supplier.  I have gone through this argument several times - the closer for me was when I went to pick up 6 bottles of 4.7 He - and it wasn't deleviered yet.  I ask why and was told it did not meet specs.  So there was no way I was goiing to grade the industrial bottles which are a lower spec to fill for my dives.



I don't have a mix station completely set up yet, but through where I work I can get a discount on all kinds of gas (industrial, medical and aviation, not to mention helium.) After paying roughly $55.00 for a fill of 21/35 in a set of double LP85's at a local shop. It's time to get going.

I start my home fill station - because I couldn't even buy Nitrox in 1990 in the midwest - One shop did blend 60 minutes plus each way from my house.  If it was currently avaible at the hours I needed it.  I doubt I would fill from home.  But that is a choice every person can make for whatever reason - now where this is going.

I don't see this as an outrages price - and I can only break it down partily as I will not know all the LDS variables.
Air fills I guess are 10-20 in doubles - so you best case savings is $45.00
Now firgure in the cost Todd has for a fill station $1000.00 (for your first fill plus the air at your LDS)- which is a contiual expense and work towrds a break even point figuring in waste and gas loss - your supply bottles need to maintain pressures to get your fills.
Next out of that entire $55.00 shops need to supply everything listed plus maintain a $5000.00 plus compressor ( many shop comprssors are more then this), rent a building to keep it in, and pay someone to fill it, and utilites. 
Air fills and mix fills can be one of the biggest pain in the LDS.  I am sure any mix diver on the board has been around a fill station for more hours then they would have liked.  Add some beers and make it fun - but if it is not for convience and a true need - saving piles of cash off your fill station will take a while.  You might also get a lot of new friends as they can save a couple bucks off your investment.  I bulid a few every year for customers.
Yes this above opinon comes from myself which I consider to be an LDS for some.  I maintian 15 bottles on lease annualy and the gases are a large expense - next month my accountant will probaly ask me again why I do this....  It simply is because I have to.  Continue disscussing away.  I believe gas grades were covered pretty well already...

[/quote]

[ethanb]

Greg -

I'd be interested to hear more about the tech diving scene in the midwest in 1990 (since Nitrox would've been considered "tech" back then).  There's so few people on this list who have been diving the Great Lakes that long - it'd be great if you could share some of your diving experiences from the early 90s. 

Ethan

[divbum]

Greg -

I'd be interested to hear more about the tech diving scene in the midwest in 1990 (since Nitrox would've been considered "tech" back then).  There's so few people on this list who have been diving the Great Lakes that long - it'd be great if you could share some of your diving experiences from the early 90s. 

Ethan
[/quote]
We always share plenty of stories over beers at the end of the day - come join us sometime.
The guys that were prominent in the Great Lakes since the 60's - 90's probaly don't have computeres.  I wouldn't even consider myself actively tech until mid to later 90's.  It has been quite the evolution.  and I really can't hunt and peck that long on a key board - but I can babble forever.
Black Magic in Libertyville was the first shop in IL to offer any formal training and fills. In thinking a little harder I will say 1990 is off a little should have been early 90's.  But even into the late 90's Nitrox was hard to get in IL.

[Corndogg]

I started diving trimix last spring and was also disgusted with the price of fills.  I had plans to buy a compressor, a booster, and set up a mixing station at a cost of over 5000. I still think its fun to mix gas and thought it would be more conveinient.  However, I could never win the argument over the back mounted self contained portable gas blending and recycling system: 

The Rebreather

[Chris H]

I'm sure there aren't any costs associated with owning a rebreather.... :

Care to break it down for us?  I can start.  One Inspiration Rebreather $6000....

[divbum]

Which rebreather have you purchased or are planning on?

[chuck_northrup]

I would like to preface this statement by saying that saving money on gas fills is NOT a reason to buy a rebreather  :-*  Saving money on a gas blending station however  >

By the time everything is "said and done" with a rebreather (CCR Trimix ready) you are looking at an investment of around $7000-12,000 depending on the unit and "aftermarket" additions (training included)  :-\

BUT, a (GUDC retail price) gas fill is about $20 for Mix and $20 for O2.  These cylinders (13-25 ft3) provide an approximate 6-12 hours of diveable time.  This would equate to around $200-800 worth of OC gas (depending on SAC).  Greg mentioned earlier that mixing is a lost leader for diveshops so even mixing yourself those numbers should be fairly close (especially adding in compressor costs)  :o

Stage bottles could stay filled all season long...unless the SHTF or you are prudent about practicing bailout drills    I once had a former student diving with OC Mix divers for the first time...he couldn't get over the fact that EVERY dive they made they had to drain their stages 

I dive AL 19's on my KISS and  I can dive 4-5 dives (at almost any depth) without changing cylinders.  With larger cylinders the gas would last longer, but considering you have a 3 hour scrubber duration it doesn't make much sense.

You may be wondering about bailout options, I have high-flow quick-disconnects plumbed into the Open Circuit DSV so all of the "off-board" or bail-out gas I carry can be directly injected into the unit without needing to "switch" mouthpieces or regulators  ;D 

Take these numbers and apply them to your "average" diving year and see where you end up...but don't let that number justify whether or not you dive a rebreather  8)

Chuck Northrup
Going Under Dive Center

[divbum]

Hey Chuck -
Good info, could you add a little bit more like cost to fill your scubber.  I know 3 hours but when would you say on average you refill it 2 hours or do you always get three.  And approximate cleaning and dissinfecting times and cost ( which most likely cost less then the beer I drink filling but for grins) Next is how often would a unit be serviced like an annual over haul or x hours.

I know you VIP your can annually >  - the last comment is an inside joke

Thanks