Home brew nitrox

[MNawman]

This question is for all those who mix their own nitrox. I want to start blending my own mix of EAN. I have the basic and advanced nitrox certs. I also have a portable Nautica compressor to top off with, and an O2 sensor. Are there any courses out there that teach you exactly how to fill your own bottles with EAN? I have worked in a LDS and have filled hundreds of bottles with air, so I've got that part down. What I want to know is how to blend different mixes as well as what not to do. I also want to fill my own Argon bottle. I am a welder and have the big bottles of O2 and Argon. Thanks for any info.

 

[roakey]

Immediately buy this book: http://www.airspeedpress.com/newoxyhacker.html

Roak

 

[ageddiver]

That is exactly the book to buy. Read it carefully. Mixing your own Nitrox (or trimix for that matter) is not difficult, but absolutely requires you to maintain your equipment clean and oil-free, as well as observe a number of safety rules. Using your own compressor also means you'll want to maintain it to a higher quality as well, and have the air tested more frequently. After reading the book I'd also recommend actually watching someone who's been doing it for a while so you can ask questions.

Good luck!

 

[pescador775]

You implied that you want to "blend gases". That is a flow process which suggests that you intend to use an atmospheric pressure chamber, aka "nitrox stik". The other type of nitrox process is called PP mixing and that involves decanting a gas into a scuba cylinder followed by injection of a second or third gas usually with a compressor. I suggest you read the Hacker's Companion with an eye towards building a stik. Come back after reading the book.

Argon can be transfilled or pumped into a cylinder. This requires a booster, cascade or special compressor hookup. The latter method should be possible for small quantities of argon and is a practical method when supply pressures are too low for transfilling. Every gas is different and some will generate more heat in a compressor than others. Otherwise, this is exceedingly easy to do. Purchase a single stage regulator called "Mistral". Test and make sure it is in good shape. Remove both hoses from the regulator. Using an adapter to the argon supply tank, connect the Mistral to the supply tank. Run a clear plastic hose from the output of the Mistral to the compressor intake. Pressurize the Mistral and start the compressor. Fill the small argon tank with gas.

 

[Scuba Cowboy]

You could also take a gas blender course from an instructor whose experienced in blending gases. This, in conjunction with the Oxyhacker book, should give you the basics to get started.

 

[ageddiver]

Ahhh, that just takes the fun out of it

 

[kidspot]

the Oxyhacker book IS fun... he's got a great writing style that's quite memorable (in a good way)

 

[rjack321]

Build yourself a booster for the argon though. It generates alot of heat in a compressor. You can build one for less than $300 from a hydraulic cylinder and some check valves.
Airspeed Press has a book about them too, although I modeled mine after a friend's
http://pg.photos.yahoo.com/ph/rjack321/detail?.dir=a616&.dnm=52a9.jpg&.src=ph

I drive mine with scuba gas, although you can also build a frame and use a jack to drive the cylinder (in which case you don't need a double acting).

 

[JEScholz]

I have the "handbook" and it is full of practical common sense ideas! If you have been filling cylinders, you should be able to to either PP mix or blend. My understanding is that blending requires less equipment modifications since you never deal with O2 higher than 50%.

 

[MNawman]

Hey guys, I got the handbook, great reading. Thanks for the info. I do a lot of welding, so I have most of the tanks and gas except for helium if I get into trimix. I get good deals on the gas and cylinders from the local welding supply store. I have a portable Nautica dive compressor which I was hoping to use. I haven't read that far into the book yet, but does anyone use such a compressor for PP nitrox, and if so, how do you clean it for O2. I had thought about adding a second filtration unit and changing out the compressor oil to a food based oil. Hopefully this info will be in the book, but I always like to hear from people who have done it before. Thanks again guys.