Spectrum 375 X-Treme vs. Hobart Airforce 500i CFM Requirements?

[Arizona Joe]

The Miller requires 5 CFM @ 90 psi. The Hobart requires 3 CFM @ 90 psi. The specs show that they have comparable performance.

1. Any ideas as to why the Hobart requires so much less air?

2. My Porter Cable 20 gallon compressor is rated 5.3 SCFM @ 90 psi. Of course that does not take into account hose resistance. Also, I'm up at elevation 4600 ft. Any opinions as to whether my compressor is up to the job for the Spectrum?

[Bodybagger]

At 4600 feet, that compressor will operate at about 85% of its sea level efficiency, or 4.5cfm@90psig.

The air demand is determined by the size of the orifice in the cutting tip. As you cut, the hole will enlarge and your air demand will go up. That tells me the Hobart has a smaller tip which tells me it will do better on sheet metal and worse on plate.

Unless you're using this on a cnc plasma table, you will not be using it at a high duty cycle.

You'll be fine. The size of the tank should keep it running well into the duty cycle.

[Arizona Joe]

At 4600 feet, that compressor will operate at about 85% of its sea level efficiency, or 4.5cfm@90psig.

The air demand is determined by the size of the orifice in the cutting tip. As you cut, the hole will enlarge and your air demand will go up. That tells me the Hobart has a smaller tip which tells me it will do better on sheet metal and worse on plate.

Unless you're using this on a cnc plasma table, you will not be using it at a high duty cycle.

You'll be fine. The size of the tank should keep it running well into the duty cycle.

Thank you for that thorough and illumating answer. My intended purpose is sheet metal. Cutting 1/4" material I expect would be rare.

The Spectrum 375 is very attractive, especially its weight and size, and what I intend to buy. Again thanks

[Bodybagger]

I own a 375 Extreme and the only thing negative I have to say about it is that I use it so much, I'm out of practice cutting with oxyacetylene. I got it for cutting aluminum, copper and stainless steel. But since at least 80% of what I deal with is less than 3/8" thick steel, it does the lion's share of my hot cutting. Once you get good with it, you'll love the way stock keeps much cooler than flame cutting. And by the way, the New model has a better torch than mine.

Do yourself a favor and get a mini filter-dryer to couple onto the air input and feed it with 100 feet of air line to allow the compressed air to cool prior to hitting the dryer, which allows the water to condense in the dryer bowl much better. Keep your gouge tips from touching the work piece and together, those two actions will GREATLY increase the life of your consumables. Forget about in-line desicant dryers. They saturate very quickly.