plasma cutter help needed

mroldstyle · Jan 20, 2011

Let me start by saying that I just got a plasma cutter, with no previous expierence. So I got it all hooked up, dissecant air dryer, filter, regulator, 50 amp breaker and started cutting. Well the results were anything but spectacular. I'm sure all due to technique. I realize theres a learning curve but thought maybe I could get some direction on here to shorten it up alittle. I statred out with 3/8" steel, had no problem geting through it, the problem was the slag building back up and "welding" the cut right back together. I tried going faster, going slower, more amps- less amps (40-50) more air - less air (50-70 psi) all with similar results. I started off using a standoff but had better results free hand, but still ended up having to go back several times to get a cut through. What am I doing wrong?
Thanks for any help.

jimcolt · Jan 21, 2011

Plasma cutters are not all the same. They perform differently, must be used differently, and have different capacities. If you provide us details about the make and model system you are using, I'm sure we can chime in and help!

Jim Colt

gwdixon · Jan 21, 2011

You might check the air pressure while the cutter is running. A long air feed line or a small in-line desiccant air dryer can cause a significant drop when the line is opened for cutting.

Removing the restriction or shortening the line will give you a fix if that is it. Plasma cutters have a high air demand.

When at rest, the air pressure will build back up to the correct setting and fool you.

mbrule · Jan 21, 2011

I would have to look at mine, but that air pressure sounds high to me.

You might want to try working with some thinner material to practice. I only have a small unit, forget the model but it is Thermodynamics smallest and maxes out at 3/8", I use mine mostly for sheet metal, in my experience, heavy slag is a result of too much current or a worn electrode.

Take it for what it is worth, I am no expert. But, when you get used to it, you WILL love it!

Mark @ Everlast · Jan 21, 2011

What unit do you have? It would help to be able to know. What type start?

mroldstyle · Jan 23, 2011

I have an Everlast powerplasma 50. After a little more use over the last two days its working better, so its probably a technique problem.
Thanks

Mark @ Everlast · Jan 23, 2011

It can be experience, and technique, for sure. However, give me a call and we can go over some basics. Also some pics might give a clue. Any slag formation should not "weld" over, and shouldn't reach significant levels until you get to about 3/4" or more.

One thing worth mentioning, is that the "standoff" has to be adjusted for best distance. Usually you have to adjust it to be closer to the metal, around 1/16 of an inch, no more than about 3/32. 35 amps and under should be able to be cut by drag cutting, without any issues, allowing clean bottom cuts. Too far of a standoff will result in a lot of slag on the back side.

mroldstyle · Jan 23, 2011

how do you adjust the stand-off? Also there was as much slag on top of the cut as the bottom.

J_J · Jan 23, 2011

The cutting air pressure for the Lincoln Pro-Cut 55 is 70 psi for 25 ft torches, and 75 psi for 50 ft torches. The air flow is adjusted with the purge button which gives full air flow. To much slag is caused by too much stand off.

Stand off is usually 1/8 to 3/16 in.

Mark @ Everlast · Jan 23, 2011

60-65 psi is ideal, for our torches, especially with the torches 15 ft or less. If you are getting slag on top, then you must be trying to cut like an O/A torch. You must be right on top of the metal to cut it with a plasma. The wire standoff is easily bent to the distance. Care to post pictures of the problem/unit?

Barring any issues with you missing the swirl ring, loose consumable or a issue with pilot arc transfer (which it shouldn't be if you are hacking through 3/8"), that is really about all that could happen.

Again, keep the torch about a 1/16" off the metal.