Brazing with propane and oxygen generator?

I have a very long drive to my gas supplier. As my OA tanks draw down, I am rethinking my situation.

I never weld or flame cut steel, I only braze.

My heat requirement is to join bicycle sized tubing and bed frame angle steel.

Has anyone used a medical oxygen generator as a source for brazing oxygen?

If so, how many liters/minute are required for my heat requirement?

All hints/comments appreciated.


Reply to
Loading thread data ...

Can't answer your questions but if you happen to have a Tractor Supply store anywhere near you they now carry welding gas and will swap out your tanks for a very reasonable price. And they'll take any other suppliers' tanks on trade; you just have to sign something stating that you are the owner of the tank(s).

Some Northern Tool & Equipment stores have it now as well but I think ALL of the Tractor Supply stores carry it now.

They both carry this brand:

formatting link
Best Regards, Keith Marshall

"I'm not grown up enough to be so old!"

Reply to
Keith Marshall

Medical oxygen generator doesn't produce pure enough oxygen for welding torch let alone cutting torch.

Reply to
Roger Duncan

Yep, I do it all the time.

I only do small stuff with a small torch though, a Minox No 2, larger than a jewellers torch but not full-size. Perhaps a little larger than those Bernzomatic ones with disposable cylinders. I _could_ braze bed frame angle with it, at a push, but I'd prefer something a bit bigger. I use butane just because it's easier for me.

My oxygen consumption at full blast is a bit under 1 lpm.

I have a DeVilbiss 5 lpm concentrator, cost £170 nearly-new on eBay. It's way more capacity than I need for my small torch - I could run six of them off it.

I wouldn't expect you'd have any problems using a 5 lpm concentrator.

If it's any help, 5 lpm is about 11 scfh. Looking at some tip charts, that's comfortably enough to weld 1/8th inch steel, so brazing bedframes should be a breeze.

I also expect you could build a gas accumulator without very much difficulty if the flow rate from the concentrator isn't enough or you have to do an occasional bigger job. I sometimes fill party balloons with oxygen when I want to do a job away from the concentrator. Remember, the oxygen concentrator can happily work 24/7/52.

Just don't start using compressors unless they are designed for oxygen - that will get you dead.

three things - concentrators are bigger, use more juice, and are noisier than you'd expect (or than I naively expected) (though I live in the quiet countryside, no cars, the birdies are chirping as I type). I keep meaning to put it in the attic and plumb the oxygen in, but haven't gotten around to it yet.

that said, I am delighted with mine. One of my best purchases (it was cheap too!)

Reply to
Peter Fairbrother

Eh? Where did you get that idea? You don't need more than 90% pure for welding/cutting. 80% or less will do in a pinch.

The oxygen from a medical concentrator is usually better than 98% pure. Sure, at high flows it goes down to maybe 95%, but that's still plenty.

I use it all the time.

Reply to
Peter Fairbrother


Many thanks for the person who has been there and done it!

Is the Oxygen used directly from the concentrator to the torch or do you use a regulator?

Are there safety precautions to consider?

Approximately how much pressure does it deliver?

I like your independent attitude and youir practicality.


Reply to

Directly. A propane regulator will be useful, and possibly essential, but an oxygen regulator is not needed.

I use butane and don't use any regulators at all - this means I have to adjust the torch after a while as the tank gets cold and the pressure drops. No biggie, but it's one more thing to think about while brazing, so you might well do better using a propane regulator. Especially if you already have one!

I use one-way valves, mainly because I had them already. Should probably use flashback arrestors too, but I don't. I would if I used a big propane bottle.

I don't really need the one-way valve on the oxygen line, as there is another one in the concentrator, but it's always wisest not to trust valves.

dunno, a few psi - plenty to run a welding torch, but probably not enough for a cutting torch.

Just looked it up - 8.5 psig.

Hmmm, 8.5 psi and 11 scfh - it might just be possible to cut maybe 16g sheet, if you could find a suitable nozzle - Ernie?

I'm also told that it's wiser to not to run a concentrator at more than 80% capacity, as it will last longer that way.

However, as they are reckoned to last 100,000 + hours, and I have mine switched on for about an hour a day, that's not going to worry me overmuch.

Reply to
Peter Fairbrother

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.