[Pinski]

I would have sworn I'd seen on here that folks had picked them up at Home Depot.  They looked at me like I was nuts. "you mean propane?"  No. Oxygen. SOL today. 
So, where have folks purchased the oxgen supplies to oxygenate the wort prior to fermentation?  Thanks again!

[Hokerer]

Don't know if you have Lowe's (similar to but better than Homer) out west but...

http://www.lowes.com/pd_91314-13877-307343_0__?productId=3087507&Ntt=oxygen&pl=1&currentURL=%2Fpl__0__s%3FNtt%3Doxygen&facetInfo=

...whatever home improvement joint you hit should have it in the soldering/welding section.

[tygo]

My local home depot has them. Like hokerer said it's in the welding section.  I just picked up another the other day.

[Pinski]

OK, thanks guys. I'll try again tomorrow. We do have a Lowe's and I'm not brewing until Sunday so I've got some time. 

[mxstar21]

Not sure about the mainland, but here in Hawaii they are getting hard to find.  Ace, Home Depot, and another local hardware store quit carrying them.  You might be able to find them at welding supply store, or a gas supply store.

[darkmorford]

My local Home Depot also sells them. They're in the welding section near the propane and MAP gas. Look for a bright red canister.

[thomasbarnes]

Ideally, you're wanting food/medicinal-grade oxygen. Go to a medical supply store.

[mxstar21]

You are probably better off with one of these http://www.northernbrewer.com/brewing/brewing-equipment/fermenting-equipment/aeration/aeration-system.html

These work pretty good as well http://www.northernbrewer.com/brewing/brewing-equipment/fermenting-equipment/aeration/siphon-sprayer.html

[tygo]

Ideally, you're wanting food/medicinal-grade oxygen. Go to a medical supply store.

Seems like most people that aerate with O2 use the welding tanks.  What's the difference?

[punatic]

Not sure about the mainland, but here in Hawaii they are getting hard to find.  Ace, Home Depot, and another local hardware store quit carrying them.  You might be able to find them at welding supply store, or a gas supply store.

The Home Depot in Hilo has them.

[mxstar21]

Not sure about the mainland, but here in Hawaii they are getting hard to find.  Ace, Home Depot, and another local hardware store quit carrying them.  You might be able to find them at welding supply store, or a gas supply store.

The Home Depot in Hilo has them.

I should have specified the island.  They are getting hard to find on the Leeward side of Oahu.  The places I have found them were on closeout, and they weren't getting anymore.  This was 3 -5 months ago.

[jeffy]

Ideally, you're wanting food/medicinal-grade oxygen. Go to a medical supply store.

Seems like most people that aerate with O2 use the welding tanks.  What's the difference?

Medical oxygen costs more. 
The purity of welding oxygen is just fine.

[thomasbarnes]

Medical oxygen costs more. 
The purity of welding oxygen is just fine.

You're right. I did some more research on this and my info is out of date. To count as medical or food grade (USP) oxygen must be at least 99% pure and be odorless. These days, for convenience, most distributors sell just USP O2. The only real difference between grades is how the tanks are filled and, at higher levels, the degree of purity. Oxygen tanks are routinely flushed to remove high levels of contaminants before they are refilled, since acetylene/oil + oxygen + compression = bomb.

In terms of purity, there are multiple grades of oxygen, although exact grades vary depending on manufacturer and state regulations. The lowest level will have at least 99% purity; with the remaining 1% usually being some combination of water vapor, CO2, CO2 or hydrocarbon gas (e.g., methane, acetylene). The highest grade is "Grade 5" or "5-9" oxygen, which is 99.999% pure and is used in research. The various grades below that differ in what compounds other than oxygen remain in the tank. Different grades are used by divers, aviators and for medical purposes, but for brewing any grade will do, since the trace contaminants are at trivial levels.

Good info here:

  http://www-personal.umich.edu/~lpt/oxlabel.htm

and here:

  http://www.c-f-c.com/specgas_products/oxygen.htm

@ Punatic. If you're seriously hurting for O2 cylinders, I bet that there are a lot of dive shops in your area.

[punatic]

Ambient air is only 21% O2. That's why bubbling O2 gas is preferable to an aquarium air pump.  Dive tanks mostly use compressed ambient air.

They still sell the small tanks of O2 at The Home Depot here in Hilo. 

[Pinski]

I  found the 2.1oz, oxygen tanks at Home Depot. Unfortunately, they didn't sell regulators individually so I had to buy the mini-torch kit because it was Sunday/BrewDay and all the specialty shops that likely have them were closed.  Anyway, got what I needed and now I have 10 gallons of Denny's Rye IPA fermenting vigorously! Thanks for all of the great suggestions!