Possible Plasma issues

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I got a plasma cutter from Nothern tool.  I have had it for about 1 week, but just got the chance to try it.  It seems to cut good, but I have to "scratch" the surface to get the cut started. The pilot arc seems to start and will "pop" a couple of times and then stop without starting to cut. If I retrigger it will go again.  Sometimes I can start a cut without "scratching" the metal but most times I have to.  I also tried it on expanded metal. If the pilot arc is working right should you have to retrigger and scratch the metal as you move to each cut on expanded metal?Thanks for any help you can give.   Big Mike.
Reply:The only thing I can think of is you are not getting a good ground. I have a TD plasma and one time I forgot to hook the ground clamp on and i was having some trouble like you are. After hooking the ground clamp on the plasma cut steel like butter.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:I'm with jamlit, the plasma will cut through darn near anything, but the work lead won't. If there is paint, heavy scale or heavy rust, clean a spot for the clamp.
Reply:Thanks for the info. Some of the metal was a little funky. Some I ground clean and still seemed to have an issue.  When I get it started it cuts like butter.  it is just a little hard to start with just the pilot arc.  If I "scratch" it, it normally goes real good.   I will try it again and make sure to grind down where the ground clamp goes.  I may get a chance tomorrow if it does not snow,I have to work outside Oh I did have the clamp off 1 time and managed to hit the metal I was trying to cut with the tip and I heard a loud pop from the machine. I am not sure what that was about.  It still cuts after that I am not  sure if that is when the issue with starting a cut also started to happen also or if I was having issues before that.Last edited by bigmike6970; 01-06-2008 at 08:22 PM.
Reply:By some manufacturer design the pilot arc is not self sustaining and will cut off shortly if a valid cutting arc isn't struck. On mine anyway. After about four false starts and the machine makes you wait a bit before trying again.
Reply:Thanks again. I will give it a try with clean steel and see what happens.