Plasma, I forgot, What does it do?

[Willie B]

I wanted a plasma cutter. I tried a cheap one, didn't like it. I sprung for a Hypertherm 45XP.

Today I wanted to take a shortcut. I've had a couple pins on the Case backhoe repeatedly lose the snap rings. These pins are double end, no need for snap rings on both ends. My plan was two thick washers for each. One 1/2" thick fits the pin. Another is 1/4" thick will weld to the end of the pin.

Today I confirmed; Plasma moves steel from where I don't want it to somewhere else I don't want it.

I could have used the lathe, that'd take forever. As is, I've spent two hours grinding four washers to functional shape. I "cleaned up" with an acetylene torch.

[12V71]

I wanted a plasma cutter. I tried a cheap one, didn't like it. I sprung for a Hypertherm 45XP.

Today I wanted to take a shortcut. I've had a couple pins on the Case backhoe repeatedly lose the snap rings. These pins are double end, no need for snap rings on both ends. My plan was two thick washers for each. One 1/2" thick fits the pin. Another is 1/4" thick will weld to the end of the pin.

Today I confirmed; Plasma moves steel from where I don't want it to somewhere else I don't want it.

I could have used the lathe, that'd take forever. As is, I've spent two hours grinding four washers to functional shape. I "cleaned up" with an acetylene torch.

A 45 is a bit short on power for freehanding 1/2" unless you're really steady. I have a 65 and it (and I) struggle at times with 1/2" freehand. I've learned to make pattern jigs and use a straightedge with a drag tip. Otherwise I would do 1/4" with a 000 cutting torch tip and 1/2" with a 0.

[Simclardy]

I wanted a plasma cutter. I tried a cheap one, didn't like it. I sprung for a Hypertherm 45XP.

Today I wanted to take a shortcut. I've had a couple pins on the Case backhoe repeatedly lose the snap rings. These pins are double end, no need for snap rings on both ends. My plan was two thick washers for each. One 1/2" thick fits the pin. Another is 1/4" thick will weld to the end of the pin.

Today I confirmed; Plasma moves steel from where I don't want it to somewhere else I don't want it.

I could have used the lathe, that'd take forever. As is, I've spent two hours grinding four washers to functional shape. I "cleaned up" with an acetylene torch.

it should cut 1/4" no problem? I have the 65powermax so not the same but on 45amps i would expect to be able to cut 1/4". is your air getting through properly?

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[Munkul]

a 45XP should blitz through 1/2". I've seen one guy take the outer shield off his 45XP, and with a very slow and careful cut, manage to get a relatively clean cut through a 35mm pin. I wouldn't have believed it except i know several people can cut 25mm clean with them.

Even my cheapy cut40 can just about sever 1/2".

Problem with plasma is that it doesn't burn up metal with oxygen like OF does - instead all it does is melt and move it. You have to plan for where that metal is going to be moved to... usually through the other side of the sheet... but if not, then it;s going to come back out...

[Willie B]

My son showed up yesterday morning with a cheap Land pride scraper blade his Father in law had bent into a curve with a 25 HP Kubota tractor. He wanted to straighten it & reinforce it.
The plan was to remove the edge bolts & bolt a 3/8 wall Angle the length to stiffen it & add weight.
His shortcut was cut 8 3/4" holes in 3/8 with plasma. He struggled with it, used some language the railroad workers 3/4 mile away (I'm sure) heard & were shocked!

When he was done, I set out to make my four washers. I've seen a bigger washer used as a template. I have two circle cutters for it, but they work best on bigger circles. I cut free hand to a line. It doesn't cut square, it leaves a series of "peninsulas" inside the hole. Unlike a torch, I can't clean up irregularities, it just won't start except on a sharp edge.
It pushes the steel around onto the back side of the plate. LET THE GRINDING BEGIN!

Thinking about it this morning, I had painted with the compressor Saturday. I was at 40 PSIG. I asked Seth if he turned the pressure up. He assured me he had. I bet he did not.

[whtbaron]

Yea... they like to breath... running without turning on the air compressor doesn't last long...

[Willie B]

Nope.
5 HP compressor (Ingersoll Rand) 80 Gal tank, It was set over 100 PSIG. I'm not sure what the problem was, but air pressure wasn't it.

[M J D]

The plasma will throw error codes if pressure is low. Sounds like worn consumables or poor technique.

[MinnesotaDave]

Hey Willie, I can tell you they don't cut like a torch, that's for sure. Very unforgiving freehand in my opinion.

Every tiny movement is transmitted to that tiny little cut.

With a torch, while supporting my hand appropriately, my cuts look very straight.

Same technique freehand with my plasma, little saw-tooth like marks show up "for no reason."

Oxy/propane good....plasma bad....

[Willie B]

Hey Willie, I can tell you they don't cut like a torch, that's for sure. Very unforgiving freehand in my opinion.

Every tiny movement is transmitted to that tiny little cut.

With a torch, while supporting my hand appropriately, my cuts look very straight.

Same technique freehand with my plasma, little saw-tooth like marks show up "for no reason."

Oxy/propane good....plasma bad....

Even if the cut at surface level is good, it's unpredictable what it'll do 1/8" away. I can cut a useable bolt hole with torch. Plasma, I have to grind back side clean (no easy task), then clean it up from the other side. Torch, if I get a sawtooth I can remove it, walls of a cut are square.

[MinnesotaDave]

Even if the cut at surface level is good, it's unpredictable what it'll do 1/8" away. I can cut a useable bolt hole with torch. Plasma, I have to grind back side clean (no easy task), then clean it up from the other side. Torch, if I get a sawtooth I can remove it, walls of a cut are square.

The dross on the backside from plasma often comes off way easier with a chipping hammer than by grinder - in my opinion.

That crap (dross) is super hard...

[Lis2323]

The dross on the backside from plasma often comes off way easier with a chipping hammer than by grinder - in my opinion.

That crap (dross) is super hard...

A wide bricklayer chisel works well.




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[12V71]

This is a chunk of 3/4" plate I was playing with freehand. The 65 will do it but I'm not always with it. I am getting better with it and use the O/A torch less and less. Oh, the bottom of the cut is untouched.

[Lis2323]

This is a chunk of 3/4" plate I was playing with freehand. The 65 will do it but I'm not always with it. I am getting better with it and use the O/A torch less and less. Oh, the bottom of the cut is untouched.

Beauty

Freehand plasma 1.25”





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[Lis2323]

I just sold my 100 amp Miller Plasma cutter

This is my freehand with oxyacetylene today on 3/4”.



Like Dave mentioned. Way easier cutting freehand with a cutting torch. Better control with the longer body.


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[12V71]

I just sold my 100 amp Miller Plasma cutter

This is my freehand with oxyacetylene today on 3/4”.



Like Dave mentioned. Way easier cutting freehand with a cutting torch. Better control with the longer body.


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Good point, I would love to see a plasma torch that mimics the balance of an O/A torch with a 90 degree head and a length that matches the average size and maybe even an uncomplicated top mount switch.... Might make it easier for us old dogs to adapt.

[Lis2323]

Good point, I would love to see a plasma torch that mimics the balance of an O/A torch with a 90 degree head and a length that matches the average size and maybe even an uncomplicated top mount switch.... Might make it easier for us old dogs to adapt.

Couple of old guys looking for the solution to a problem that doesn't exist to 99% of the welding population. LOL.


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[Willie B]

Wow! I can't do that with either, but life or death, I'd try with oxy.

[12V71]

Couple of old guys looking for the solution to a problem that doesn't exist to 99% of the welding population. LOL.


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Too true.

[farmshop]

Plasma takes some practice. Guides definitely help the results. I have a homemade circle cutter that work down to about 2” diameter. I have used washers both id and od to cut circles. I think letting the drag shield rest on the material takes some getting used to. If you try to hold it off the work piece things get ugly fast

[Lis2323]

Plasma takes some practice. Guides definitely help the results. I have a homemade circle cutter that work down to about 2” diameter. I have used washers both id and od to cut circles. I think letting the drag shield rest on the material takes some getting used to. If you try to hold it off the work piece things get ugly fast

Agreed. For freehand plasma cutting its hard to beat using a drag tip and a stencil or guide.







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[farmersammm]

Good point, I would love to see a plasma torch that mimics the balance of an O/A torch with a 90 degree head and a length that matches the average size and maybe even an uncomplicated top mount switch.... Might make it easier for us old dogs to adapt.

That is what I absolutely hate about my plasma.............................the ridiculous short length. A long O/A torch adds stability, and helps to make straight cuts freehand. I'm not a guy that can cut anything without resting my left hand on the plate, and using it to steady the torch. Some guys can, but I never could. I'll do it in a pinch, but I'm never satisfied with the results.

[Munkul]

Nope.
5 HP compressor (Ingersoll Rand) 80 Gal tank, It was set over 100 PSIG. I'm not sure what the problem was, but air pressure wasn't it.

Most plasmas like to run around 60psi in my experience

[whtbaron]

Hmmm.... I'm assuming that's the line pressure coming in and he would have another regulator set lower at the plasma. With my cheapy Chinese plasma I've been holding the pressure down to 90 lbs incoming and setting it around 65.

[Brand X]

That is what I absolutely hate about my plasma.............................the ridiculous short length. A long O/A torch adds stability, and helps to make straight cuts freehand. I'm not a guy that can cut anything without resting my left hand on the plate, and using it to steady the torch. Some guys can, but I never could. I'll do it in a pinch, but I'm never satisfied with the results.

90 degree torch, and long handle is pretty worthless for anything other then bench work.