Gshuma,
Hey , well, we've just about kicked this dead horse into multiple after lives. For speed, ease of training and reduction of operator error (since your friend is already used to acetelyne), nothing is going to beat acetelyne simply because it is the hottest flame of any of the commercially available gasses. Reflecting back on my original response, that was "shop line pressure"! Actual at the hose to torch  pressures are going to be much lower. If I were your friend... I'd have already converted over, bought a couple of N/G tips  and be enjoying the FREE ENERGY!!!!!(back at the Armco shop in the 70's, we built "weed burner style torches" with compressed air boosters that would make a 20' long flame for pre-heating 7,000# sub-sea wellhead assymblies, I also think the N/G would have worked fine on thicker stuff only or production schedulers wouldn't allow us the time for preheating) Just like any new variable in proceedure, equipment or materials, there will be a learning curve. Yea, the money saved on just one large bottle of acetelyne will buy a few new tips. ENJOY that free gas!

Thanks
I didn't remember that the pressure had to be so high.

I'm curious - I've never tried natural gas as a fuel - do you have any info on how that compares to using propane? (As far as cut quality goes)

I must disagree with the statement that propane gives a bad cut.  I work as a tankie, ie build large fuel storage tanks  and I have to say we never use acetylene as it is way to expensive for the amount that we burn... Propane and MAP gas work just as well as acetylene, you just need to change your cutting tip for a MAP OR PROPANE,  the cut speed is a little slower  but I have made great cuts daily with little slag,,, point I am trying to make is if you kknow how to burn to can use any fuel and make a great cut,,

Dennis speak true stuff.

Acet. will give you a concentrated high temp quicker per unit than others like natural gas that provide more BTU's per unit and has larger preheated area.

They will all produce quality cuts. But Acet. gets left  in the dust for preheating.

I have to disagree with your statement that "you will have slag no mater what process you use". From 1/2" through 3" plate with natural gas my cuts were normally slag less. They were square at the top and square at the bottom. When you worked six 10 hour days and all you do is run that machine you had to do something to brake up the boredom. I messed with speed and pressures until I could get it just right. My machine had a pre heat lever that would give a blast of oxygen to start the burn just before you put the machine in gear. The start would be square. Speed and heat would control the slag. When I first started to work on the burning table the slag looked like grapes! My goal was no slag. When the plate was 4" and up my goal was to have no tightly adhering slag. That is the kind that you can knock off easily with a scraper-- no grinder necessary.

Dennis

Although i never cut with NG I have done alot with propylene and i gotta say, i mastered the slag less cut on anything I cut, and as dschlotz says, if there was slag, a 4" wide scraper did a nice job of removing it!