Onboard Nitrox System

[padimanatee]

Again, thank to all for the information. We've decided at least one thing. We've placed the Bauer for sale on the equipment board. It's a good compressor for air, but i feel, after reading some of the older threads, that it would be best to get a new compressor if we are going to pump nitrox.
The question I have now centers on O2, and the choices of onboard production or supply. First, for onboard production, what filtering must be done for the low pressure air, if we go with membranes.
If I just carry oxygen, can I use large (new) aluminum tanks which have worked well for the Argon we used for aluminum tig welding...or must I use steel. Are there any issues with pure O2 in aluminum tanks? The aluminum argon tanks are about 5' tall and I can lift them!
They don't hold as much, but I can move them easily. I've also thought about a "portable" nitrox bank system. Not everything onboard. Just moving large nitrox aluminum tanks which we fill dockside.
The boat can be seen at Ted Brewer Yacht Design under aluminum sail, shennigan.
We are only going to take 4 or 6 divers, and I hope some rebreather folks, so I don't really need huge supplies for some of the trips.
I wish I had found this board earlier because the advice is excellent and I truly appreciate the time people take to reply.

[rjack321]

Large ~125cf aluminum O2 tanks with CGA 540 valves do exist. Its a matter of finding them and a gas supplier to fill them. The gas industry is weird and you may not be able to track down a supplier.

[padimanatee]

I found some DOT 2015 aluminum O2 cylinders with 265 cu ft cap, the pressure rate is 2015 psi. Empty they are 93 lbs.
Maybe this is the answer. Anyone have any recommendations on a technical course for nitrox blending and fill operations?
I can see there is a lot to learn.

[DennisS]

I found some DOT 2015 aluminum O2 cylinders with 265 cu ft cap, the pressure rate is 2015 psi. Empty they are 93 lbs.
Maybe this is the answer. Anyone have any recommendations on a technical course for nitrox blending and fill operations?
I can see there is a lot to learn.

Have you read Vance Harlow's Oxygen Hacker Handbook

Vance Harlow's OXYGEN HACKER'S COMPANION From AIrspeed Press

[rjack321]

Why do you want AL supply cylinder so bad? They are "non-standard" in both the welding and medical O2 universes and are probably gonna be tough to get filled.

[padimanatee]

I'm going to get the book!! I can see why it is so popular!
When we started to build the boat, I bought two aluminum cylinders for argon (for TIG welding) and it was one of the best decisions we made. We use one while our gas supplier fills the other. Weight is my main reason for using aluminum. If you look at the layout of the boat, you will see two lazarettes on either side of the aft "dive" compartment. These have watertight deck hatches and I can lower my current argon tanks and they stand up nice and safe, so what I need is oxygen tanks about the same size. If I put oxygen on one side of the boat, I'll have it in a gas tight compartment away from any source of problems. Almost all the aircraft people I've spoken with, use aluminum, and smaller aluminum cylinders are common in medical applications so I don't think filling would present a problem. There are some real high tech alu tanks wrapped in kevlar and stuff, but I think it's just as easy to use aluminum.

[rjack321]

If you are successfully getting the AL filled with argon you should be able to get them re-valved and filled with O2 at the same supplier.