What does it mean ...........

When there is a lot of porous spongy glop on the underside of a flame cut that takes a lot of time to grind off and dress?

Too much what? Wrong speed? Help me.

1/4" thick steel, 4# propane, 20# oxygen 00 tip.

Steve

OK. Try less preheat (possibly a different tip style, for example if you had an Airco torch you could go from a 164 tip to a 144 tip to a 124 tip ..), try moving faster, look closely at the severed workpiece to see if the top of the kerf rounded off, if so try raising the tip when you cut.

Grant

I hate three words: maybe, should, and probably.

Steve

The top of the cut looks nice. Almost square. I hold the torch at a very small angle pointing forward in the direction of the cut. As I cut, there are little globules that take off across the top planar surface of the metal. I know this is something simple, and would sure help me save some time dressing it up afterward.

Steve

Way to many variables here. But one that I haven't seen posted yet is how clean is the metal. If you want a clean cut the metal will have to be clean. It's pretty much impossible to cut rusted metal without slag with a cutting torch.

Next is the accuracy (can't really think of a proper term) of the oxygen jet. If the jet is a nice linear flow that stays small for a long distance (say 3-5" from the torch tip when depressed away from the metal) then you've got it right. If it gets turbulent a short ways from the tip then there's part of the problem.

Last is a tip for getting rid of the slag. If you'll take a standard hammer (not a chipping hammer) and hit along the corner where the slag is you can usually pop most of it off. If you insist on grinding then grinding along that edge at a 45 deg angle will be much more efficient than trying to grind it flat. The slag is only stuck along cut edge.

I think the word you are searching for is 'clean'. Anything that disrupts the clean flow of the cutting jet will cause a dirty cut. Tip cleaners should be used often but very carefully, the motion must be straight in and out as any side pressure on the tip orifice will make it bell shaped and cause it to behave more like a gouging tip than a cutting tip. If the tip has a damaged orifice it may be necessary to file it shorter to remove any belling of the cutting orifice.

Check the condition of the tip by looking at the side of the flame with the cutting valve open, the cutting jet should be a thin dark line in the center of the flame and free of any turbulence or feathers out to the side of the jet, or a jet that gets wider as the distance from the tip increases. A simple, plain and dark background will make the flame and jet clearer and more visible.

Lack of oxygen pressure can cause incomplete steel burning in the cut and lead to excesive slag. Check the surface of the cut, the striations on the cut edge should be square and straight, any curving of the striations can indicate lack of pressure or excessive travel speed. The guage may be defective or the hose obstructed or undersized. 20# oxygen seems a little low especially if the hoses are long or undersized. Too much pressure is wasteful and will consume excess oxygen, but will not degrade the cut. I like a large hose with a short, smaller and more flexible whip on the torch. Unsteady hands can cause a rough cut and excessive slag, get comfortable, make a practice movement to check for binding or dragging hoses, and keep the torch as steady as possible when cutting.

A 3-4" wide piece of old planer blade or similar welded to a heavy handle makes a large chisel that is a good tool for removal of slag, just use it flat on the bottom of the cut plate and slide it towards the cut and underneath the slag.

A proper cut with a CLEAN tip will cause almost no slag to adhere to the cut edge and the little that does will be very easy to remove. It should almost never be necessary to use a grinder to remove slag. In general, any need for grinding is caused by a dirty or oversized tip or lack of cutting oxygen pressure.

Always remember that with OA you are burning the steel and not cutting it. You are NOT melting the steel and blowing it away, that process is ArcAir.

Good luck,

"Private" wrote

In general, any need

From all this, it looks like too low O2 pressure. The steel was new. The

00 tip was adequate for 1/4" plate. Will try it again, maybe tomorrow if I need to cut something.

Steve