Hey guys,
I know this is a welding board, but i figure a lot of you probably use and/or own plasma cutters, and i can't figure out the best place to get these questions answered.
I'm looking for suggestions for a plasma cutter. There are really only 2 things i want, but i can't seem to find them together in the same machine. They are: built-in compressor, and capability to cut 3/8 steel (I don't care how slow it is at 3/8", i'll probably only use it for that thickness very rarely)
It's for a home shop, so it won't be subjected to heavy use, nor do i need high max speeds. I don't need a top-of-the-line machine, but I don't want a no-name machine either. I want the portability given by a built-in compressor, and i want 3/8 capability because i ocasionally cut 1/4 to 3/8", and i don't want to under-size the machine.
The only one i can find that has both is the thermal dynamics "Drag-Gun Plus" but at roughly $1600 internet price, it's a couple hundred more than i want to spend.
Anyone have any suggestions?
I had the same thought process that you are asking about, and came to a different solution. The built in compressor adds some cost to the machine, usually $2-400, and also increases the amp draw considerably. After looking at the options, I found that I could buy a small pancake air compressor for less than $150 and save the price difference on my plas machine. You still have the portability, but now you have to lug around 2 things. As long as your not cutting long runs (mine is 24 inches max) the pancake compressor will keep up fine. One word of caution that I learned the hard way is that if you're going to run this in the field from your generator, your max thickness is limited to about half. The reason is on my Miller 2050 plas, it has a monitoring circuit that watches the incoming voltage and when it drops 10-12% from the required amount, it automatically shuts down. So what you wind up with when the plas fires off at the start of the cut, the generator has a momentary voltage drop as the motor lugs down and the governor kicks up the fuel based on the motor load. This causes the monitor circuit to kick the plas out. I have to drop the plas amps to about 1/2 or slightly higher so it does not have that initial voltage drop so much. I run this set up 2-3 times a month as I need to and it performs well. I'm running this off of a Ranger 250 which has a 10K generator output.
Mark
why not flip the high idle switch and no worries about amp droppage
Shad,
Even if the high idle is on, the initial amp draw from the plas causes the same problem. I talked to Lincoln and they said that the early Ranger 250 did not have a smooth surge compensation when high amperages draw, it takes a second or two for the power to smooth out.
Amen to that!!! Cannot run my Lincoln inverter V-205 off my early Ranger 250 beyond 150 amps for any AC welding process on the inverter. Multiple phone calls to get this figured out. Got a Miller CST 280 inverter for DC remote TIG and it runs fine off the the same Ranger 250. Looking to replace that Ranger 250 this year as it fully depreciated. Wondering if this problem of running secondary inverter welding machine from Ranger 250 has been alleviated?
Thanks!
I have a decent air compressor, which is no problem if i use it in my garage, but if i want to take it anywhere, my compressor is too big to be "portable"
In addition, i don't have a lot of space to store a "second" compressor. That's why i was really looking for an all-in-one solution.
Unfortunately, i think i may have to buy a small compressor. How small of a compressor can i get away with?
Mike944:
I have been researching essentially the same problem, since I have a Miller Spectrum Thunder (built-in compressor) for light duty work (max 1/8"), but would like to cut up to 3/8" with good cut results and speed. So far, looking at compressors, I have decided that the minimum would be a 10 gal. (to avoid extensive recycling while cutting) with over 4 scfm at 90 psi., oil lubed for durability, and vertically stacked for small footprint. I think that anything smaller would not have the air pressure or volume required to cut 3/8", but I would like to hear from more experienced users about this.
Another problem I have run into that limits portability is the operating temp. range of the compressor. A couple of the cheaper models I have located that meet the above specs. are 32 - 95F, which definitely limits winter portability in my part of the world.
I personally don't like them. With the Miller made Hobart Airforce 250, you end up spending more money on consumables in the first 6 months, then you would have if you'd spent the extra for the Drag Gun. But from a repair shops point of view, Hypertherm makes the best plasma cutters available. And their consumables last longer.
http://hypertherm.com/languages/english/powermax190c.phpJMO.
Kay:
While I agree that the built-in compressor types can be expensive in consumables because of moist or contaminated air, the advantages of making very clean cuts with low heat input, and being able to cut non-ferrous metals outweighs this for me. I think I can make a low-cost compressor with filter and dryer, combined with something like the Hobart Air Force 400, work portably on up to 3/8", although not in all weather conditions.
Mike944 and I would like to hear from anyone out there that has tried this. (I also realize that the 400 would only cut 1/4" non-ferrous, at best).
How much cutting are you guys talking about? Sure moisture is a consumable killer for plasma cutters, but I don't do anyting special on my air system other than a bulb type water trap, and the consumables last for quite some time. I'm not making precise cuts, but it's well withen the allowable tolerances for joint fit-up. I only use a no name 5 gal compressor and it keeps up fine for the field work I need to get done.
MDG Custom Weld:
Thanks for the info above, which is exactly what I wanted to know. All I want to do is to cut up to 3/8 steel at a variety of locations, with fit-up accuracy, and have the option to cut light non ferrous. Based on your experience, I think my most economic choice would be a small compressor and something like the Hobart AirForce 400 (has a little more cutting capability than the Hypertherm Powermax 30, and is still portable, although not as light.)
I think you will be happy with the results. It's not like we are doing production cutting in the field. It's just an added tool in the tool box that makes us more efficient and helps get more work done in less time. I have been using my no name compressor for 2 1/2 years and its still going strong (sure dosent look like new anymore).
NW-
The 400 is different from the 250. No "built in compressor"
http://hobartwelders.com/products/plasma/So you are talking about a better grade of machine. Everyday I see customer who bought the AF250 because of the built in compressor and are not happy with it. Go with a standard cutter and buy a small compressor, you will be alot happier.
Well, i gave up on trying to find the built-in compressor in the size i want. I just ordered a Hypertherm Powermax 30. I guess i just won't be taking it out of my shop, unless they have an air compressor.
I have successfully used compressed air bottles as supplied by my welding gas vendor for field work. This was much easier and cleaner than the compressor situation. I was very surprised when I first did this how inexpensive and long lasting this actually worked out to be. Not recommended for prolonged plasma operations such as gouging. But really nice for cutting operations. You would be shocked how much cutting you can do with a 250 cubic foot bottle. Hopes this helps!
XpertFab, the tanks your describing, are they like the carbonfiber firefighting air tanks?
What pressure are they rated at and how much do they cost to buy/rent?
-Clif
Hmm! Never had the opportunity to use the tanks you mentioned. I am speaking to tanks of compressed air such as provided by your welding supply that are the same type of cylinder that is used for Oxygen and the other commonly used compressed gases in welding. These are usually steel tanks pressurized to 1800 psi or so. I imagine those firefighter style wrapped tanks would work also if you had access to them. In principle all you need is a clean source of dry compressed air and a method of regulating it. I wonder if the type of regulators as used for breathing oxygen would be able to flow the CFM that is required for Plasma cutting. I am certain someone who uses this stuff daily could comment more specifically as to the CFM of these types of regulators. (breathing type)
Thanks for the interesting thought!
I know people who run air tools off the primary circut of SCUBA equipment, I think 6-8 CFM would not be a problem. What flow do You need?
6 Cfm at 90 Psi will run most 1/2" plasma cutters.
Forum
