Quote Originally Posted by Stustoys View Post
You dont care(if you're talking about buy a cylinder from Speed Gass) you just change it over like swap and go. But 10 years I believe is the answer to your question..... but then, I might be out of date myself. lol


There was a guy around that did that sort of thing with argon cylinders. Emptying one full cylinder into 3 empty ones, getting about 87.5% of the gas out. You'd want to be careful... things would get hot and cold. There was a pump on ebay a while back for transferring the dregs of many cylinders into a full one........I controlled myself hehe

Stuart
Stuart, that was me. And no, things do not get hot or cold if you allow about 10 to 15 minutes for the transfer. The donor cylinder does not get cold enough to show condensation. The receiver cylinder will not even feel warm. But that is Argon, an inert gas. I would not recommend doing diy transfers with Oxygen unless one is very confident about what he is doing.

But..... another idea instead of using bottled Oxygen. What about an oxygen generator, sometimes refered to as an Oxygen concentrator. These units are used by people with medical breathing conditions, where a cylinder would have to be replaced daily. These units contain a small oil free membrane air compressor. The air passes through a oxygen concentrator that essentially lets esacpe Nitrogen and humidity out one end, and Oxygen out the other end (Air is made of 78% Nitrogen and 20% Oxygen). The Oxygen purity depends on flow rate (low flow about 98% pure Oxygen, high flow about 70% pure Oxygen, in any case pure enough for brazing and welding purposes). Such units cost new around $5k. But many elderly/sick people have little choice and buy one. And when they pass away, these units may pop up on eBay for $500-1000. Cheaper than renting bottles, and for occcasional use power consumption (about 500W) is negligible. Google it up if interested, here a video: https://www.youtube.com/watch?v=UXD_J8PxUnE
I came across the idea when my wife needed Oxygen, and we were loaned such a unit by the hospital. It has been returned since.... but the idea remains.