HELP! Lincoln Pro Cut 25

Can anyone help me figure out what I’m doing wrong? This is the quality of cut I get no matter what settings I use. Plasma cutter is a Lincoln ProCut 25. Material is steel, roughly 1/8" thick. No matter what I do I get a ton of dross on the backside of the cut. I have yet to have a part “drop out” after being cut.

I’ve tried:

slowing the feed to 7in/min
turning the power down until it doesn’t cut
turning the power all the way up
adjusting the height of the cutting head from between 1/16" and 1/8"
used the table with and without water
changing the plasma tip
…and every possible combination of these items.

Is the ProCut rated for 1/8" cuts? I’m assuming you’re running 25A. That may not be enough.

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It is rated for 3/8 and we are running it on 220V.

It has no problem cutting the thickness, in fact it will almost do it on the lowest setting. No matter what we do it makes copious amounts of dross like in the photo.

I’m thinking speed is too slow and maybe you need a little more air pressure. I understand slow speed causes this dross because the arc is dwelling too long and melting too much material which then builds up on the back


try 70inches a minute


Try much higher, like 120-140ipm. I had terrible cuts like that at 30-50ipm @40amps on 1/8" then started getting clean, straight cuts at much higher speeds @ 30 amps starting at 110ipm and getting better up until about 140.

Also, check the condition of your electrode and your dynamic air pressure while it’s cutting.

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Thanks, everyone! We will definitely try cutting faster. The fastest we’ve tried so far was 60ipm, which by the sounds of it is the lower end of where we should be. Most of our cuts were in the sub 30ipm range. Air is set to 55psi as stated in the manual, but I will wiggle a bit there too.

try 65psi and make sure that’s when air is moving

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I use 10% or 10psi as a rule of thumb for pressure loss in a 3/8" air hose for every 100 feet which is very conservative.

Or use a calculator if you want exact.

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So we had another go this past weekend at higher speeds. We started at 150 and worked our way down. It absolutely refused to cut through until we were in the <20ipm range, which then gave us the awful slag on the backside. We are at a loss…

This is from a 130ipm pass.

Seems like your cutter is only energizing the pilot arc.

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Is there a way to test this out? I don’t know enough about plasma cutters to tell if we are just seeing the pilot arc or a cutting arc. It will cut a slow speed, but I don’t know if a pilot arc is capable of cutting at all.

Do you have the work clamp attached to the metal, one of the slats, or the water table drain plug if you have one? Even at 25 amps it should be able to cleanly cut 1/8" steel at 50-80 ipm. From the pictures, the cutter is merely gouging the plate at significantly less speed which looks identical to what you would see if the cutter is only on pilot arc.


Yes, we were grounded to the drain plug.

Drain plug doesn’t work for some people. Try a short cut with the clamp directly on the material.

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We will give this a shot. Might be a few weeks before we get a chance to play with it.

That sucks, hopefully you get it worked out soon. It took me a good 10 weeks of messing with it and trying different things. It wasn’t until I added a refrigerated dryer last weekend that I started getting absolutely beautiful cuts in 16G up to 1/4". It’s quite the learning and tweaking process for some of us and other’s have great success almost straight out of the box.:man_shrugging:

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Good call on the dryer, I’ll have to check ours just to make sure everything is working. What cutter are you using?

I’m using one of Harbor Freights older cutters with a Trafimet S45 torch I’ve had for a while. I was hoping to get away with it for now and upgrade to a Hypertherm 65 next year but I was seriously doubting this thing’s ability to get me through until then. Turns out it was a moisture problem, not a cutter problem. It’s such a relief to be making quality cuts though.