First of all there is nothing wrong with my concentrator. It is a bit finicky at times but it works. My reason is noise. As I watch different videos of frame builders using, I assume Oxy/Acetylene, it is very quiet.
Though?

You can get a tank filler to go with your concentrator. And it can be hooked up to any size bottle with plumbing adapters, although the output fitting and the cradle is for the portable ones for humans.

My wife got a setup like this to do lampwork. Her torch is very hungry, needs like 15L, and she's... not that good about cinching up the plumbing, so she is often going across town to get another can. But her concentrator was 7th or 8th hand and she hasn't had a chance to get it sorted yet.

Tom, one way that those needing oxygen to live deal with noise is that they put the concentrator in another room. Or just further away.behind something. You don't need special hose (the clear plastic hose you can buy at Home Depot works fine) to run it from where the concentrator is located to your bench. You might want some kind of manifold on your bench to accept the clear hose.and that also your welding hose can attach to. Some concentrators have plastic welding B thread to barb accessories. Western Enterprises makes brass ones commonly available with different barb sizes. Those plastic or brass fittings have a B thread on one end and a barb fitting on the other. These fittings make running long lengths of clear hose possible. Of course there is some loss of pressure the longer the hose. Some concentrators have barb instead of a type B fitting.

Those of us that have been doing it a long time all started out using oxyacetylene. If you don't mind loading the tank into your car and paying $20 for each exchange, bottled O2 works perfectly. Each time you have to take the regulator off the empty tank and put it back on the full tank. And just as a reminder, acetylene is a LOT more expensive. Your local supply store may allow you to transport your own acetylene but some places are a lot more strict and they will only deliver to a commercial address. Acetylene bottles should always be kept upright.

Doug,
Thanks for the "remote" idea!
Then again there are cotton balls!!😂😂😂😂

Do o2 concentrators really affect frame building cost or is simply a matter of being able to produce the o2 needed at a super low cost after the machine has been paid off via cost savings?
I ask because I built 5 frames, replaced 1 down tube, two drop outs, brazed up a fork, and cut down a square tubed basketball pole all on a single tank of o2. Tank size is 80 cubic feet. Just recently had it filled as it was about 80% empty. The acetylene tank of the same size needs a refill as it is empty.

Those looking for brazing equipment advice are typically someone new to framebuilding and wanting to know what to get that might work best. For them getting a concentrator is probably a bit cheaper (and maybe al lot cheaper) than buying an oxygen tank and regular. And then of course they get an endless supply just on the cost of electricity. For you it would just be a matter of convenience. Taking the regulator off and putting the tank into your vehicle and driving to where the WSS is located and then setting it up back in the shop again may not be someone's idea of a good time. In the past I had to run down to South Bend almost a half hour away during 9 to 5 business hours. In your cost analysis you would have to include gas and lost working hours too.

One of the primary reasons I suggested switching to propane and a concentrator is because of regulations. Welding supply stores in bigger cities won't deliver to residential areas (and sometimes won't let you transport the bottles yourself), insurance regulations can be restrictive, etc. And some wives/partners don't like the idea of that hazard near them. Propane is a LOT cheaper and far more convenient to buy anytime. Of course going with propane means getting propane mixers and tips for best results.

I am curious why the mixer would matter for propane in the small sizes of tips that most newbies would be using. I have old factory brochures from Meco, Smith, Purox, Airco, and Harris and they all say that it is O.K. to substitute "alternative fuel gasses" without a single mention of
using a different mixer. These catalogs all date back to the days when Gas Welding and Brazing were still fairly widely used. I can understand that when using a Rosebud (especially a large one) you would have to be concerned with having a large volume of gasses flowing freely to
avoid "starving" the tip.

Victor is the only company I noticed that offered one-piece alternative fuel tips, going back to the mid-1950's catalog I have. They were mostly for the larger torches (100 and 315 series) and for the large sizes of welding tips / rosebuds.
Even way back then there are the UN-J tips for the small torches, and the UN-JJ for very low-pressure acetylene generators. But mostly Victor just offered the replaceable tips with the counterbored ends.

Propane requires more oxygen than acetylene. For example the Smith mixer/elbow AT-60 for acetylene has 4 smaller holes while the AT-61 for propane mixer elbow has 6 bigger holes. A propane flame will work with acetylene equipment. It is just that the flame blows out much more easily.

But with Victor and Smith (most of torches I've played with) the Oxygen flows through the center hole, the additional holes in the AT - 61 and the Victor UN-J are for the fuel gasses, not the oxygen.
I think it might have something to do with the different densities of acetylene and propane ?