BS,

I'll take a shot this because its raining down here and homework is fairly light this first weekend, and I don't have much else to do. Single and 2 stage, I believe, refers to the way in which pressure to your lines are regulated. As you use your tank, the pressure inside will drop slowly. If you use only a single stage regulator, constant adjustments will be required to maintain a constant line pressure. Two stage regs, however, first drop the high tank pressure to a lower pressure, where the "second stage" then further drops it. What this does is allow the lines to maintain a constant pressure as long as the cylinder is still above the required first stage pressure. Confused yet? Think of this like you would if you were trying to maintain a constant water flow. Using only a garden hose directly off of a faucet, the flow rate is dictated by flow on the hose only, and if the flow in the hose drops, you can do nothing about it. The two stage regs basically put a "supply tank" between input and output. First, you fill a bathtub with the hose and pull your flow off of the tub. Just because the waterhose drops in flow doesn't mean what you are pulling off of the tub has to drop as well-- you just pull a little of the "supply" out of the tub until flow on the hose jumps back up.

As far as cheap vs. high end, an example would be Victor. I have been told that most of the Victor compatible torches are still made by Victor themselves and marketed under a different brand name. Why they are cheaper, I have no idea. I use a Victor Performer for most of my fencework and have given my father a similar Firepower setup. The difference in price was well over $100, but the torches were identical. I believe they even had the same stamps and markings. This refers only to the castings, however. I am not sure about O-rings and machine finish qualities for valves, ect. My suggestion would be to go with the cheaper because of this and the fact that you are just starting out - This, of course, pending that someone else here does not find arguement with the differences in quality or more information on the manufacturers.

If I am wrong on either of these issues, I would more than welcome being corrected. That is simply how I have interpreted them.

Either way, hope that helps!
G. L.

Mrbillz,
I'd like to expand on previous posts...

The function of oxyfuel apparatus is well established to the point of being considered ancient by some people. They should all carry some certification of design approval- it's alphabet soup in my mind at the moment; I leave establishing precisely from whom to others.

If you have any experience with old lawnmower engines you may have noticed Briggs used the fuel tank as a reservoir for the carbourator system, while Techumseh typically had a seprate, dedicated, float regulated bowl for that purpose closer to the design of production automotive carbourators. You can think of a single stage regulator as the Briggs line of thinking, and the two stage as the more consistant rationale Tecumseh favored, which, in practical functionality, provides a mix less dependant on fuel level (or in this case pressure) because of the additional reservoir constantly maintained at a predetermined volume of fuel.

In the case of regulators, a diaphraghm conducts tank pressure to an opposing spring, the adjustable tension of which meters a [needle] valve, and through it the flow of gas. The (tank) pressure upon this adjustable spring varies somewhat as the gas in the tank is expended.
A two stage regulator has a first stage wherein the tank pressure is regulated at a factory-set valve which supplies a constant feed pressure to the user adjustable, working (line) pressure stage.

If you use a manifold you typically incorporate two pressure control devices (one at the tank, another at the station) which perform exactly as a two stage regulator.

I wish I could link you to an illustration.

Finally, consider this... Briggs dominated the market despite the "inferior" single stage design of their fuel system. The issue was one of practicality.
Here, there probably won't be a noticible difference between the function of one and the other unless you are running the torch wide and long enough at one time to make appreciable "dent" in the supply tank pressure; you may have to occasionally fine-tune your flame, and the torch control, rather than the regulator, has been suitable to make those corrections in all but the most extreme cases I encounter... My torch runs intermittantly prehaps a maximum total of a couple hours pre day

Flow rates are the criteria upon which to base your choice of regulator type, in addition to the rate it has been designed to accomondate. (the rating should be listed with the product specification information)

Regards,
d