Plasma Cutter Questions

[AntiBling]

Well I am looking into plasma cutters, and am pretty clueless as to the operation of them.

What I have picked up so far about them:

They are the handies things to have.

If you use air line from a compressor use a good line filter on it to keep from going through consumables, which I have got.

Now the main thing I am gonna be using this for is for automotive work. Mainly cutting off sheet metal for rust repair but also some frame work.

I was thinking at first of buying a machine that is rated at a 3/8" genuine cut. I went to the local welding shop and priced them out and got a price in my head for what I would need, around $1500.

Then I went on ebay, for $1500 I could have one rated for 1/2" genuine cut.

This would be handy for doing repairs on farm equipment once in awhile (I dont farm but my uncle does and I do repairs for him once in awhile)

But my main question is, if you go with these bigger ones, how do they do on the smaller metal? Will they give as precise cut on sheetmetal? Will it cause a lot of heat that will cause warping on sheetmetal?

Also my local Prax Air, they sell Miller welders, but they sell Thermal Dynamics plasma cutters. I was talking to the guy and he said they could order me Miller Plasma cutters but he says the Thermal Dynamics ones are better than the Miller as far as plasma cutters go.

So whats your opinions?

[big rig guy]

I have the TD Cutmaster 50, three years old and never a problem with the unit. I just upgraded to the 1torch, if you buy this unit now, it comes standard with this torch, or at least I think it does, at any rate, any TD machine make sure it is equipped with this torch.

The 1/2 inch size sounds like it would fit the bill for what you are intending to use the machine for. I get decent cuts on mine, on thin and thicker stock.

I've only used TD machines so can't really say too much about the other brands, I am sure someone will come along here and chime in thier opinions too.

Can't live without mine now, sure makes quick work, wished I would have gotten a machine two sizes bigger, but I am into heavier work not needed for thicker cuts, but faster, I like the machine to cut 1/2 plate like my td 50 goes through 1/8 lol. Around the farm, a 1/2 cut model should work out very well for you I would think.

[Scott V]

I think I would go with the cutmaster 51. It's been around pretty much in the same form for a while. Big rig has the torch answer right. Great torch. I have the SL 100 machine torch on my 101 and it cuts really straight which is with hardly any bevel.
Here is a test cut from yesterday at 40 amps output and at 72 ipm on .120 MS Steel. Same exact setup as the Cutmaster 51. I do not think there is a better air-cooled torch setup going. They have changed the 50 cutmaster into the 51 to ditch the hi freq, so it will not mess with cnc machines.

[carbon]

Originally Posted by AntiBling

But my main question is, if you go with these bigger ones, how do they do on the smaller metal? Will they give as precise cut on sheetmetal? Will it cause a lot of heat that will cause warping on sheetmetal?

So whats your opinions?

Most of the plasma units have adjustable power so you can turn down the amps. I would think that you should be able to turn down the amps on a bigger unit even for sheet metal (I could be wrong) You can always turn the power down, but you can't turn it up to more than you have available. I have the cutmaster 38 and I like it alot, but I never cut anything thicker than 1/4" and cut mostly 4' x 8' expanded metal #9, and 1/8" steel. I got the cutmaster 38 because it also runs on 120v. Next time I would buy bigger. maybe the cutmaster 51.
Consumable life seems good and the quality of cut is great.

photo attached done with cutmaster38. 3/16" mild steel. The hole cut was photographed with no clean-up after cutting.

[AntiBling]

Well I think I am gonna buy the Cutmaster 51. Thanks for your help.

[ROCK]

ANTIBLING............. Well before I wen't out and bought just one brand from say 4 or 5 responses............I think I would head off to the local welding distributor's in say a 25 mile radious................Me I would take something I wanted cut and make them fire off 2 or 3 of the brands they were selling......

Then I would make up my own mind which one I like the best.........I no longer push any one brand............I simply suggest you try more than one brand.............It is your hard earned cash and no one else's...........

Make the distributor do the leg work............Heck you wouldn't want to get bamboozled would you................TRY AS MANY DIFFERENT ONE'S AS YOU CAN GET YOUR HANDS ON.....................THEN YOU DECIDE.............

[1911man]

Sound wisdom Rock, I think he was just trying to save some time by picking the collective brain here but ultimately he has to live with his decision.

[cutter]

Something I'd like to point out about these pictures that Scott V & carbon posted is that they were done under mechanized or CNC control. You're not likely to get such clean results cutting freehand or drag.
One other note: take the amperage rating seriously on the supply end. If you buy a 120v 30 amp machine, then you dang well better supply it with a full 30 amp connection, etc. My Spectrum 375 is real sensitive to that & won't cut for crap if I accidentally plug it in to a 12 gauge wire. Yep, found that out one night , just like SlimJim discovered the effects of a weak ground.

[Migmaniac]

I bought a Spectrum 375 about a week ago worked great for the fist day then i started having cut quaility and dross issues, This is what the tech guy had to say about it.


1. The tech showed up and said "well theres no debate over this unit being f**ked up"
Didnt even bother doing a diagnostic,Simply said the pilot arc was sticking on.And it wasnt outputting full amperage.That was the end of that.

2.Supplier said i had 2 options,1st being get a replacement 375,2nd being he give me a newThermal Dynamics Cutmaster 38,Well you know what option i took

He wanted to give me my money back but i said "No i want to keep my money local and not have to order one online." He liked that idea so he went ahead and let me get the Cutmaster 38 for what i paid for the Spectrum 1175.00.

Now i wish i hadnt of sold the one i killed because the torch was fine just not the unit

Not saying the Miller was a bad unit,But apparently these issues have come up before according to the tech guy.

[carbon]

Originally Posted by cutter

Something I'd like to point out about these pictures that Scott V & carbon posted is that they were done under mechanized or CNC control. You're not likely to get such clean results cutting freehand or drag.
One other note: take the amperage rating seriously on the supply end. If you buy a 120v 30 amp machine, then you dang well better supply it with a full 30 amp connection, etc. My Spectrum 375 is real sensitive to that & won't cut for crap if I accidentally plug it in to a 12 gauge wire. Yep, found that out one night , just like SlimJim discovered the effects of a weak ground.

Yea, Thanks Cutter. Those are two things I did not mention. My cuts by freehand are awful and ragged, it's better using a straight edge or guide, but it's still hard to have consistant travel speed for a pretty cut. The first two or three weeks that I had my plasma I was using it in my garage connected to a 20 amp outlet. When I upgraded the service and started to run it on 30 amps, it was like night and day.