Kevin is using his Everlast PowerPlasma 80S plasma cutter to answer these questions. It’s an 80 amp plasma cutter, rated to cut 1-1/2″ metal and sever up to 1-3/4″ metal. “Whoa! It’s like holding a lightning bolt,” says Kevin.
On the plasma cutter’s front panel, you see a pressure gauge. At first, it’s set pretty low, right around 15 PSI. Somebody (Kevin) bumped the pressure regulator and changed the setting, so the first thing he’s going to do is turn up the air pressure to about 60 or 65 PSI, where he wants it to cut some 1/8″ hot rolled steel.
Kevin cautions to be sure to push down the knob on the pressure regulator, just to make sure it’s locked in place so you don’t knock it out of adjustment.
He turns down the amperage down to 20 amps at 60 PSI and cuts the metal. Then he cuts it at 25 amps and 30 amps.
The 20 amp cut took a long time – it just barely wanted to cut through. The 25 amp cut went a little quicker, and the 25 amp cut has a little smaller kerf. The 30 amp looks about the same width as the 25 amp, but it cut so much more quickly and easily!
On the back, you can see the 20 amp cut had a big clump of dross, or slag, on the back. The 25 amp and 30 amp examples were smaller, but they were pretty similar.
Now Kevin is going to set it back up and vary the air pressure but keep the amps at 25 to find out if air pressure has any influence on the cut.
He has another piece of 1/8″ plate steel. The first cut is at 30 PSI. Next he bumps up the air pressure to 40 PSI. Next he cuts at 50 PSI. He skips 60 PSI where he did the first set of amperage tests, and he jumps up to 70 PSI.
Looking at the cuts head on, you can see that there’s a big blob of steel in the 30 PSI cut. The blob of metal in the 40 psi cut is smaller, in the 50 PSI cut the blob of steel is even smaller. The 70 PSI cut has the smallest amount of dross.
On the back, you can see that, on the 30 PSI cut, the dross almost filled the cut back in. The 40 PSI cut is better, the 50 PSI one is better yet, and the 70 PSI cut is the clearest of all.
Kevin says this indicates that it’s not amperage but air pressure that matters for a good, clean cut. As long as you have enough amperage to cut through your metal and cut at a decent rate of speed, turn up the air pressure a little more to get a better cut.
However, be sure to READ YOUR MANUAL! Make sure you know how high you can set your air pressure. Don’t over pressure the machine – they are only set to go so high without blowing a hose off or doing other damage to the machine. The manual will give you the range your machine can handle.
Like Kevin, you can go back to other matters, unless you want to see him lose his place ….