Learning to use my new plasma torch

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Just got a new Longevity 60i plasma cutter and am trying to learn how to use it.Tried a few cuts on 1/8" carbon steel using a guide bar and running about 45 amps.  Unbelievably fast and smooth.Then tried a few cuts on 3/16" aluminum...same 45 amps but no guide bar.  Not as straight (understandably) but what bothers me is that the cut is much rougher than the CS.Any of you guys have any suggestions for getting smooth cuts on aluminum or is it that I just need practice.Also, the Longevity has adjustable output and an amp meter which is nice (I guess) except that the meter doesn't indicate the setpoint but only indicates the amps while the torch is operating.  So you have to pull the trigger and then look at the meter to see the current reading.  When you let off the trigger, the meter reads 5 or 6.  The current adjustment dial doesn't have any numbers on the scale so you have to trial/error/guess to get a specific setting.  Seems dumb....or maybe I don't understand something...or maybe it's defective....or maybe I shouldn't worry about specific settings and just settle for low/medium/high.Other than that, this is the first time I've fooled around with a plasma cutter.  This thing is awesome.  I can't believe it cuts so fast and smooth...at least on gauge steel. Attached ImagesMiller 211 w/ spool gunMiller Dynasty 200DXLongevity 60i IGBT plasmaO/A w/ crappy chinese torch/gaugesSouth Bend 10K latheGrizzly 4029 10x54 millGrizzly 7x12 hor bandsawangle grnders, bench grnder, bench belt sndr7.5 hp 80gal cmprsor
Reply:Try it with a guide, you can't make a comparison using 2 methods on 2 different types of material
Reply:I don't think the finish is as good on alum as it is on steel, no matter which plasma is being used.  That's been my experience anyways.My name's not Jim....
Reply:Thats pretty typical for aluminum with an air plasma. You'll get better with time! Looks good, glad its working out for you!Jim Colt
Reply:Thanks for the responses guys.Tried the aluminum again.  BTW, I was wrong....it's 1/4" not 3/16" (didn't have my glasses on).  This time I used a guide to get a straight cut.  I varied the output (40 to 60 amps) and the air pressure (50 to 70 psig).  The cuts are straight (thanks to the guide) but still rough.I called Longevity and described the problem.  They advised that aluminum won't cut as clean as steel (just as Boostinjdm said).  They said that this is because the cutter is DC only.  If it was AC (as available on their multi purpose machine) the cuts would be cleaner.  No big deal as I mainly need this to turn large sheets into small stock to finish on a mill.They also said that the amp meter only reads correctly when the torch is cutting.  I tried setting the output control to full and cutting the 1/4" alum while watching the meter....reading was 63 amps...OK.  Still seems weird but I guess we won't worry about a few amps one way or the other and just assume that half way up means roughly 30 amps.Question:  Electricity bills notwithstanding, is there any problem just running the torch at full throttle no matter what I'm cutting and forget about the output adjustment feature?  Premature consumable failure would be my guess but hey I'm new at this.Miller 211 w/ spool gunMiller Dynasty 200DXLongevity 60i IGBT plasmaO/A w/ crappy chinese torch/gaugesSouth Bend 10K latheGrizzly 4029 10x54 millGrizzly 7x12 hor bandsawangle grnders, bench grnder, bench belt sndr7.5 hp 80gal cmprsor
Reply:If you run the machine wide open your going to get lower quality cuts on thing sheet. There is such thing as too much power with these things. I would run the machine on about 25 amp for 3/16" and under then crank it up as needed for thicker stuff. I have a Hypertherm so Im not sure of the adjustability range of the Longevity product, but I'll assume it has a reasonably wide range. And the comment about the AC plasma cutting aluminum, I'm not sure there is such a thing, hopefully Jim Colt knows, but it sounds like someone might have AC v DC welding of aluminum confused. But anyway, like the guys above said, plasma is not the best tool for cutting aluminum when a good finish is needed. I do all mine on the waterjet.If you cannot convince them, confuse them.         Harry S Truman
Reply:There is no such thing as an "AC Plasma". They may be referring to the AC welding capability of the combo machine.....but when it is in plasma mode it is DC. Or...if it is a high frequency start.....high frequency is AC.....but that is just the ionizing arc.....does not support the plasma arc.Jim Colt
Reply:Hi there,I have a 110V HF plasma cutter. IT's discontinued and I picked it up for $300.  Problem is that there werw some parts that leave me puzzled as to how they are interconnected. Spedicifcally the electrode is spring loaded and is able to push the torch through to the ceramic difusser. Is this normal?I "thought" that the electrode would be the friendly way of creating constant FH arc stabilization.  bottom line, is there going to be a workable sharing of the supper effect. I bet that you'rll have much greater satisfaction around