Plasma cutters

[nobleswood]

Dear All,

I thought I'd tap into the collective knowledge here.

Plasma cutters for the small shop. What experiances & recommendations do members have ? I won't be cutting thicker than 6mm steel & while I want something that works well I don't like spending money. Often I'd prefer 2nd hand.

What are the recommendations ?

Cheers

[OregonAl]

I had excellent performance from a Hypertherm Powermax 65. That's probably more than what you need for 6mm cutting. Maybe the 45 would suit your needs better. Not cheap but very good quality and service.

[RinkRat II]

 I'll add that a major consideration is the size and capability of your air compressor. Be sure to find the air requirements of any cutter your looking into and  add a little extra to help reduce the duty cycle.  My $.02

        Paul B

[canuck750]

Avoid the Lincoln small unit that sells for around $1000. I bought one and it died in under two years. The motherboard is non serviceable and it became a paper weight.

[Trialsman]

My Hypertherm has been with me for about 15 years.  Just used it the other day for sectioning drawer units from a storage cabinet.  It will cut sheet metal about as fast as you can draw with the tip.  Great tool but not cheap.  I paid for mine by selling off some take-off shocks and carbs from some 70's bikes.

[nobleswood]

Thanks all,

I'll see what I can find 2nd hand & looking for the Hypertherm.

[redhawk47]

Hypertherm or ThermalDynamics only!

I went to a welding and cutting sales pitch years ago. The salesman said "I love the cheap plasma cutters from HF and others. Guys buy them because they want to try plasma cutting and they are cheap. They find out how useful they are, and then the machine breaks, and isn't repairable. So they come and buy a good one from me."

[nc43bsa]

Avoid the Lincoln small unit that sells for around $1000. I bought one and it died in under two years. The motherboard is non serviceable and it became a paper weight.

Non-serviceable as in not available anywhere at any price?

[Hymes Inc.]

Have an Eastwood versa cut 60. Does a pretty good job. Few years going and no issues.

[MotoChuck250]

Another vote of confidence for Hypertherm and Thermaldynamics.  Have used both.

Make sure that you have enough air compressor and also a good air dryer setup.  Moisture in the air will cause plenty of aggravation.

[Chuck in Indiana]

The Kid and I were talking about tools this weekend. He said, "this reminds me of the 3 dollar shovel story.. a guy needed to bury his cat and didn't have a shovel. He drove 20 miles to town to the hardware store. They had a 3 dollar shovel and a 20 dollar shovel. Thinking he only needed to use it once, he bought the 3 dollar shovel and drove back. It promptly broke, so he made another 40 mile round trip and bought the 20 dollar shovel."
Get the good tool. You'll eventually forget the price you paid, and never be aggravated or *injured* by a cheap one.

[nobleswood]

The Kid and I were talking about tools this weekend. He said, "this reminds me of the 3 dollar shovel story.. a guy needed to bury his cat and didn't have a shovel. He drove 20 miles to town to the hardware store. They had a 3 dollar shovel and a 20 dollar shovel. Thinking he only needed to use it once, he bought the 3 dollar shovel and drove back. It promptly broke, so he made another 40 mile round trip and bought the 20 dollar shovel."
Get the good tool. You'll eventually forget the price you paid, and never be aggravated or *injured* by a cheap one.

 
But I would be happy with a 'used' 2nd hand shovel for $10- 

[tcunnien]

I have had a Thermal Dynamics hand held plasma cutter in my high school school shop for the past 8 years and it used almost everyday. It has held up very well to use by high school students. Nothing has broken on it yet. Depending what your cutting it might be worth your while to look into the small plasma cutters that have their own built in air compressors. Almost every major manufacturer has a model that they sell. Can't go wrong with Hypertherm or Thermal Dynamics either.

[nobleswood]

I have had a Thermal Dynamics hand held plasma cutter in my high school school shop for the past 8 years and it used almost everyday. It has held up very well to use by high school students. Nothing has broken on it yet. Depending what your cutting it might be worth your while to look into the small plasma cutters that have their own built in air compressors. Almost every major manufacturer has a model that they sell. Can't go wrong with Hypertherm or Thermal Dynamics either.

Because I’m not familiar with what’s available I’m asking vague questions I guess, but it’s the small portable cutters with the built in air compressor that I was thinking of originally.

[73eldorado]

I have a small Miller Plasma that I’ve had for 20 years, still works with no problems.

[rodekyll]

Just curious -- how clean do affordable plasma cutters cut, how precise are they, and what is a nominal max. thickness of material?  Could I accurately cut sheet metal?  do plunge cuts?  round holes?

[73eldorado]

Just curious -- how clean do affordable plasma cutters cut, how precise are they, and what is a nominal max. thickness of material?  Could I accurately cut sheet metal?  do plunge cuts?  round holes?

My Miller plasma is a base model and when you cut metal it does not require any clean up or grinding. As for precision that’s up to the operator and the thickness it will cut depends on the model. Not sure on the plunge cuts but it can cut round holes with a little practice. Buy one and practice you will not go back to a oxy acetylene or arc air after you learn to use a plasma.

[canuck750]

Non-serviceable as in not available anywhere at any price?

Oh Lincoln will sell me a motherboard, for the sum of $725.00 each.

[pyoungbl]

Just curious -- how clean do affordable plasma cutters cut, how precise are they, and what is a nominal max. thickness of material?  Could I accurately cut sheet metal?  do plunge cuts?  round holes?

The cut can be as clean as a drill hole, it's all about how the operator is using the tool.  As for thickness....that depends on the machine.  The higher the amp rating the thicker the metal.  You can easily cut sheet metal with almost any plasma cutter.  Plunge cuts are doable but it's cleaner to have a pilot hole because during the plunge the cutter is spitting metal back.  Round or square holes are just a function of how steady you are.  It's really like drawing with a pencil where you cannot erase.  Make sure your air supply will support the machine you get.  I have a machine that will do 3/8" metal and it has been all that I need.  The machine is at least 15 years old now and has been flawless.  For thicker I use oxy/acetylene.

Peter Y.

[Groover]

Are plasma cutters CAD driven, or are they a manual tool?

[rodekyll]

You say it's like an unerasable pencil line.  I get that.  Good analogy.  Is the kerf (width of cut) also pencil-line fine?

[73eldorado]

Are plasma cutters CAD driven, or are they a manual tool?

Both, mine is manual but my bud who has a welding shop has one that he has to program and it follows the program.

[Rick4003]

Are plasma cutters CAD driven, or are they a manual tool?

They can be both. The plasma machine itself doesn't really care how you move the torch. Most lower powered machines are meant for manual handheld cutting but can also be setup for CNC. It just depends on if you hold the torch yourself or let a CNC table hold it for you and then tell that what to do. Most of the lower end machines only comes with the handheld torch and cannot be fitted with a machine torch. often the higher end machines are build with CNC capability in mind so they have extra plugs to link the controls with your CNC machine interface and the torch is often exchangeable so you can install a machine torch.

Then again a machine torch is not a must for using your plasma cutter on a CNC table. plenty of people have just made a holder for the handheld torch and used it on their CNC.

- Ulrik - Who would like to have a plasma cutter... and a CNC table to go with it :)

[rodekyll]

My welder does up to 1/4-inch, if I'm meticulous.  What would be the recommended specs for a hobby grade machine that would work 1/4" steel?  Do they do aluminum sheet like airframe and skin?  What features would a hobby level fabricator want in a plasma cutter?  I'm seriously thinking about upgrading my current cutting technologies, which are oxy/ac and angle grinders, but I'm on a no-income budget.

[Rick4003]

Most of the smaller 30-40 amp machines can do up to around 10mm/ 3/8"? steel and a bit less in aluminium, but airframes and skins should be easy to tackle with one of the smaller machines. You could get one of the Chinese machines that is super cheap to buy, but don't offer any product support and limited life of the consumables. I had a small 40 amp Chinese machine that worked ok until some goon stole it, my small TIG welder and two big Bosch angle grinders 

If you read the reviews on the net (I cannot remember which site) they recommended a Lotos machine as an affordable choice. Maybe worth to check out.

-Ulrik

[nobleswood]

I have 1phase 220v in my shop so could get a bit more amps for the cutter & hence get it to cut 1/4"steel mostly for the tractor & like stuff.

What are 'the consumables' and how do they work into the cost equation ?

[rodekyll]

I have 1phase 220v in my shop so could get a bit more amps for the cutter & hence get it to cut 1/4"steel mostly for the tractor & like stuff.

What are 'the consumables' and how do they work into the cost equation ?

I never know if I'm going to have 220 available or not, so I've considered convertible voltage to be a useful, although limiting feature.  My compressor and welder are both convertible.  They work MUCH better at 220v.

So you folks think that a 50amp would be a good entry point?  Does this do a conversion to 50a, or does the shore power need to deliver 50amps a/c?

[tcunnien]

The consumables are the tip and electrode. The tip has a precise hole in one end this is where the arc is focused and cuts the metal. This hole will enlarge with use. How long it last will vary with what you are cutting, amps that you are cutting at, moisture in the air that you are using and so forth. The electrode is under the tip this is where the arc starts. The electrode is also affected by the same things the tip is affected by. It has been my experience that they usually are replaced together. I cannot speak to cost as there are many different sources for consumables. from e-bay to your local welding supply store. For the machine we have at school I have found when we are cutting expanded metal we use up the most tips and electrodes. They don't like the quick on and off cycle cutting that kind of metal.

The machine will produce the maximum amps that it is designed to put out. Much like a welder. The manufacturer will list the required input. My experience is that a 220V machine will require any where from 30-50 amps input, while a 115v machine will require 20amp input.

The other nice thing about plasma cutters is that they will cut any metal that conducts electricity. Where the oxy-acetylene torch will cut only carbon steel well. Hope this helps.

[rodekyll]

So like my welder, I have a ground lead to clip to the work?

[Rick4003]

So like my welder, I have a ground lead to clip to the work?

Yes