Oxy-Acetylene cutting problems (Technique? Flame)

To set an Oxy-Acetylene torch.

1. Choose the appropriate tip size for your metal (for 1/4" you should be using a #0 in most brands of torch)
2. Set your gas pressures for the tip size (for 1/4" steel 6-7 on the acetylene, and 20-25 on the oxygen is fine)
3. Just crack the acetylene and light.
4. Increase the acetylene until the soot just starts to disappear in the flame.
5. Open the oxygen and increase until the carbon feather just disappears into the inner cone.
6. To cut clean on thin material like 1/4" you will have to tilt the head at least 45 degrees, so the flame is pointing in the direction of travel. This tricks the oxygen blast into thinking the steel is thicker. For really thin sheet metal almost lay the torch head flat on it's side, and move the torch really fast once the cut starts.

Make sure ur acetylene and oxygen pressure is a little over the minimum on the bottle gauges and thena open the acetylene on your hand piece until you see the flame seperate at the cutting tip, then turn it back a touch until it joins the tip again, then turn the oxygen up slowly until the blue tail is gone and all u can see is the tiny blue set of flames at the tip, then hit the oxy cutting lever and adjust the oxygen again so that there is no blue tail and just the little blue set of flames at the cutting tip, and thats it, dont worry about the 45 degree angle, just make sure the tip is clean and pointed directly towards the material you are cutting, your cutting speed is a big factor in a clean cut, increase your cutting speed slowly until you hear a noise that comes when the not too hot metal is blasted out by the oxygen, go too slow and the moulten metal will drip and stick to your work material, go too fast and u will either get a no cut or a shower of moulten metal that is blown back at you by the oxygen being pushed back from the work piece, the tip size isnt as important as some make it out to be, but u should be close for a clean cut, the number on the tip normally refers to the thickness of the metal it is designed for cutting eg- a no 8 tip is for 8mm, a no 12 for 12mm ect(in oz anyway), the biggest factor for a really good clean cut is preperation and practice !, have fun :-)).

I use 4# acet for almost everything, and vary O2 and tip size for thickness. Turn on the acet and light. Turn up until it quits making floating black boogers. Come up with the 02. Get the little blue flames. Hit the 02 handle. You got it right when the blue flame tips don't change length when you hit the handle.

Try to keep a 3/8" or so gap between metal and tip. Go ask for a tip chart at a welding store. Buy a tip cleaner and clean them out. Buy a couple of tips if necessary. Four is about all you need, from 00 to 2.

Keep practicing. Different thicknesses require different approaches. You'll get it.

Steve

"SteveB" wrote: (clip)Hit the 02

^^^^^^^^^^^^^^^^^^^^^ When you "hit the handle," the oxygen flow goes way up, resulting in a drop in oxygen pressure to the pre-heat flames. In my experience (and the way I was taught), you then open the oxygen until the preheat flames return to neutral.

I don't see how you could expect the preheat flames not to change when you hit the handle.

The regulator is supposed to handle that. If your preheat flames change a lot when you pull the O2 trigger, you need a better oxygen regulator, or you need yours fixed.

Grant

As I said, I don't like mine to change at all. Discussing and describing it is difficult. Doing it is easy, and each man has his own way that works for him. We all may be doing it exactly the same, just describing it differently. And getting good results. Yesterday, I had a remarkably small amount of slag to grind off. Hit the edge once at 45 degrees, and it was gone. Not sure if I did it by the book, but the end product sure looked pretty.

There's a hundred ways to cook a poodle. And it all tastes like chicken.

Steve

Get a tip chart & have an experienced had help you set it up. Use your ears; they will help you dial the flame in, too. When you hit the O2, it should sound like tearing paper.

"Grant Erwin" The regulator is supposed to handle that. If your preheat flames change

^^^^^^^^^^^^^^^^^^^^ In a perfect world, that would be true. However, the oxygen has to flow through the full length of your hose, the torch butt and the valves before it reaches the cutting tip. A small change in pressure with a large change in flow is normal. It's better to have a slightly oxidizing flame while preheating the steel, so you can have a perfectly neutral flame while actually cutting. An oxidizing preheat flame is actually hotter. Since you start the cut before the metal actually melts, it does no harm. I just finished reviewing an instructional video, which goes through this explanation.