Plasma torch help.

[Big Bri]

So i got a new Plasma torch for Christmas and took it out of the box this weekend to play with it as i have a use for it coming up. i watch the video and read the instructions and plug it in and start to play.

The first thing i cut was a piece of galv. pipe i had in the shop, (2" diam. and about 1/16" thick) i start on one end and make zig zags back and forth. "Wow" cuts like butter. now i want to cut some plate. i have a piece of 1/4" to 3/8" thick steel checker plate. its been laying behind the shed for about 5 years so it isn't "clean" steel. i hit it with a wire wheel on a angle grinder and try to make a cut. it starts out fine and i get about a foot into the cut and then the cut doesn't look so good. kinda like melted metal. also it started to skip a little (leaves a spot about 1/16" where it didn't cut. It also didn't cut all the way through after about a foot and a half.
The other thing i found is that plasma will cut concrete. . . I laid the plate on two pieces of the galv. pipe so the plat was 2" off the ground. . . well my nice painted shop floor now has a huge gouge in it where i was making my cuts
I also noticed that the plate got hot as did the pipe (the pipe was glowing)
i thought plasma cut cool

so my questions are can a plasma cut dirty steel? what about painted steel?
if so what do you think my problem is. . . is it just me (this is my first plasma)
thanks for any help
Brian

 

[leveller]

I am no expert on plasmas, but I do own one. You did not say what size or make of machine you have, but it sounds like you were going too fast while cutting the plate. You can cut dirty or painted steel, but it is hard on tips. Whenever possible, clean the steel before cutting.You will soon realize how expensive consumables for a plazma are. A new tip will cut very nice, clean cuts, but as it gets worn, your cuts will not look as nice. Another important thing, you need clean air. If you have moisture in your air lines, you will go through tips quickly, so get yourself a GOOD water filter. You will love having a plasma, Greg

 

[Wayne_H]

I have a plasma, and cutting galvinized pipe is hazerdous for your health...

What does the tip look like? did you drag it on the metal, or hold it off 1/8" or so? Are you sure it was grounded? Most problems I have with mine are when the tip is messed up and the air does not produce a fine stream.

Wayne

 

[Skyco]

Plasma cut cool? Naaahh..it is at something like 25,000 to 50,000 degrees!
Best thing I did for my plasma cutter was to buy a big inline desiccant air drier. Plasmas don't like humid air, and in the south we have that for sure, especially in the summer.
I cut through paint like it isn't there, haven't really had any trouble with rust either.
Mine is the HF 40 amp Plasma cutter, so far so good.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95136
Air drier was this one-
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97686

 

[Big Bri]

I have a plasma, and cutting galvinized pipe is hazerdous for your health...

What does the tip look like? did you drag it on the metal, or hold it off 1/8" or so? Are you sure it was grounded? Most problems I have with mine are when the tip is messed up and the air does not produce a fine stream.

Wayne

didn't know that i should not be cutting galv. metal. thanks for the tip.
the tip is brand new, i didn't hold it off as it is a "drag" tip. the directions say to put the tip at a 90 to the metal and drag.

 

[Big Bri]

I am no expert on plasmas, but I do own one. You did not say what size or make of machine you have, but it sounds like you were going too fast while cutting the plate. You can cut dirty or painted steel, but it is hard on tips. Whenever possible, clean the steel before cutting.You will soon realize how expensive consumables for a plazma are. A new tip will cut very nice, clean cuts, but as it gets worn, your cuts will not look as nice. Another important thing, you need clean air. If you have moisture in your air lines, you will go through tips quickly, so get yourself a GOOD water filter. You will love having a plasma, Greg[/quote
thanks for the tip greg, i got the thermal dynamics cut master 52, i did buy water filter, the glass bowl type. i also bought a desiccant filter but not one as large as the one skyco recomended but i couldn't get enough air through it. maybe i needed a bigger one. i blew air out of the tip on to paper and it didn't show any signs of getting wet.
maybe i just need some more trial and error.
thanks
brian

 

[Big Bri]

Plasma cut cool? Naaahh..it is at something like 25,000 to 50,000 degrees!
Best thing I did for my plasma cutter was to buy a big inline desiccant air drier. Plasmas don't like humid air, and in the south we have that for sure, especially in the summer.
I cut through paint like it isn't there, haven't really had any trouble with rust either.
Mine is the HF 40 amp Plasma cutter, so far so good.
- Harbor Freight Tools - Quality Tools at the Lowest Prices
Air drier was this one-
- Harbor Freight Tools - Quality Tools at the Lowest Prices

that is a massive drier . . . how close to your plasma do you have it ,or do you have it next to your compressor?
thanks
B

 

[Hooked_on_HP]

Even with the drag tip I have better luck holding the tip about an 1/8" off the metal. Dragging works fine on thin steel. Also what is your air pressure set at. If you are using an extension cord make sure it is a heavy one and the circuit you are plugged into is wired heavy enough.
Bill

 

[Big Bri]

bill
Have the air pressure set at 90 but once i start cutting the compressor kicks on, i'm not sure what pressure it stays at while cutting, guess i have to check that. i was using a twin tube contractor style compressor, its one of the oil less type. i thought using it would give less contamintants as my large belt driven seems to always have a little oil in the line.
thanks for the reply

 

[powerstroke444e]

1st time I used one I found that I was not going slow enough, and need dryer air?? I have a miller 375 extreme and purchased a dryer to add @ the plasma and run 150psi to it which was more than book said but the salesman pointed out that I was losing to much pressure on long cuts with 3/8" hose other wise. I would say it is one of my favorite things to play with in the shop.

 

[J_J]

that is a massive drier . . . how close to your plasma do you have it ,or do you have it next to your compressor?
thanks
B

A water filter should be next to the compressor, and the desiccant type filer at the plasma cutter. Even if you have the drag tip, if you start in the middle of the steel, turn the tip 45 degree or raise the tip up, to allow for the hot metal to blow out of the hole. Once the hole is started, turn tip 90 degrees and cut at a steady speed for the thickness of the metal. There should be a guide with the plasma cutter.

You can cut galvanized metal, just don't breathe the fumes, or fumes from any metal cutting.

Some handy tools for circle cutting. These tools can be used for plasma cutting also.

 

[toy]

I was at the local machine shop about a year ago and they had got a new toy and they had been playing around with it, you could see the metal that they had been cutting laying beside it. They had cut out stars, a moon, a heart and they looked good. The machine looked like it might have been a cnc plasma cutter and the table on it was a grating metal, and it had cut marks partially through the grating all over it and it was pretty deep. The original poster mentioned gouging out marks on his concrete floor, my question is how high would you have to elevate the metal off of your welding table to be able to cut the material that your are cutting without cutting gouges out of your welding table or the floor as the poster mentioned? My second question is the desicant material in the harbor freight filter the same as those little packs of stuff that is in packages that you order that is supposed to absorb moisture? They also say that you can replace the material in the filter, do they sell the desicant material and how much would it cost, and could you dry what is in the filter out and reuse it? Is one of the motorguard filters by itself enough to dry the air out enough to use in a plasma cutter or should you use additional means with it? The motor guard filter that I have the filter element is about the size of a small roll of toilet paper and I was told that you could dry it out and reuse it and that you could also use a roll of toilet paper for a filter, is this correct?

 

[toy]

bill
Have the air pressure set at 90 but once i start cutting the compressor kicks on, i'm not sure what pressure it stays at while cutting, guess i have to check that. i was using a twin tube contractor style compressor, its one of the oil less type. i thought using it would give less contamintants as my large belt driven seems to always have a little oil in the line.
thanks for the reply

I have a porter cable air compressor supposed to be 6 hp with a 30 gal. tank and with the pressure set at 90 psi as soon as you start using the air, the compressor would kick on but it could slowly outrun the demand and it would kick off for a second or two and then back on again. I think they grossly overrate the hp ratings of the air compressors. I have an ingersol rand two stage 80 gal tank air compressor and the amp rating falls in the right range for the hp ratings.This summer lords willing I hope to put in metal trunk line for my compressor and where the joints of pipe connect I plan on putting in t's with short down pipes so the water will collect in them and I can drain them out occasionally. The tips stuck in the switch on the porter cable compressor and the pressure gauge valve busted before the pop off valve opened up and I don't know how long it ran like that but it was getting hot. I plan on putting a new cutoff switch on it this summer and since it is portable and runs off of 115 volts I believe I can find a lot of uses for it, but not for something that demands a lot of air.

 

[Skyco]

The HF drier I have mounted on the garage wall, it is about half way between the compressor and whatever I'm using it with. I also use it for spray painting, which is rare, and inline to my blasting cabinet to be sure the media doesn't cake up.
The desiccant is replaceable, around $5 for a kilogram, which is what it holds.
It shouldn't really need replacing unless it gets oil contaminated, since a trip through the oven will revive it.
One thing I did too was add a shutoff valve to the input to the drier, it has enough volume there is quite a whoosh of air when I disconnect the feed hose, so I just shut it off with the valve after removing the output hose. Don't need one on the output since the quick connect shuts it off there, just remember to remove that hose first, shut the valve then remove the input hose.

A crazy idea I had was to extend the intake of the compressor into the house...since humidity can be very high here in the summer I figure the dehumidified air from the AC would give a head start on keeping moisture out of the system. Haven't tried it yet.

 

[wushaw]

bill
Have the air pressure set at 90 but once i start cutting the compressor kicks on, i'm not sure what pressure it stays at while cutting, guess i have to check that. i was using a twin tube contractor style compressor, its one of the oil less type. i thought using it would give less contamintants as my large belt driven seems to always have a little oil in the line.
thanks for the reply

I also have a TD cutmaster 52 and it doesn't take long to cut my 80 gal compressor on. I have a sharp dryer system with a big dessicant dryer and a Motor guard filter mounted to the back side of the machine, I wanted dry air. The machine will cut off if the air pressure gets too low.
I have had mine since last March and it has preformed flawless except when it won't get a ground, it will start then stop with a bad ground, I found this out with very rusty metal.

 

[wushaw]

I was at the local machine shop about a year ago and they had got a new toy and they had been playing around with it, you could see the metal that they had been cutting laying beside it. They had cut out stars, a moon, a heart and they looked good. The machine looked like it might have been a cnc plasma cutter and the table on it was a grating metal, and it had cut marks partially through the grating all over it and it was pretty deep. The original poster mentioned gouging out marks on his concrete floor, my question is how high would you have to elevate the metal off of your welding table to be able to cut the material that your are cutting without cutting gouges out of your welding table or the floor as the poster mentioned? My second question is the desicant material in the harbor freight filter the same as those little packs of stuff that is in packages that you order that is supposed to absorb moisture? They also say that you can replace the material in the filter, do they sell the desicant material and how much would it cost, and could you dry what is in the filter out and reuse it? Is one of the motorguard filters by itself enough to dry the air out enough to use in a plasma cutter or should you use additional means with it? The motor guard filter that I have the filter element is about the size of a small roll of toilet paper and I was told that you could dry it out and reuse it and that you could also use a roll of toilet paper for a filter, is this correct?

The flame only goes @ 1 inch, I can cut 2X4 tube and it will not do anything to the other side.
Plasma cutter will cut "ANYTHING" that conducts electricity, so keep fingers out of the way

 

[toy]

Thanks wushaw, I have been wondering about that. I was hoping that a little elevation on your material above your welding table would let you cut it without destroying the table beneath it.

 

[kennyd]

bill
Have the air pressure set at 90 but once i start cutting the compressor kicks on, i'm not sure what pressure it stays at while cutting, guess i have to check that. i was using a twin tube contractor style compressor, its one of the oil less type. i thought using it would give less contamintants as my large belt driven seems to always have a little oil in the line.
thanks for the reply

What is the CFM rating of that compressor? I bet it's not close to what that PC need to operate properly.

 

[ovrszd]

A crazy idea I had was to extend the intake of the compressor into the house...since humidity can be very high here in the summer I figure the dehumidified air from the AC would give a head start on keeping moisture out of the system. Haven't tried it yet.

Little off subject, but I decided I would protect my Jeep engine when wheeling in water by running the engine intake into the cab. Sure stopped the problem of sucking water into the engine. Sure made the cab cold in the winter!!! Sucked all the warm air out and the heater couldn't come close to keeping up!!! Might find your house HVAC struggling to replace all the cool air you remove.

 

[ovrszd]

The tips stuck in the switch on the porter cable compressor and the pressure gauge valve busted before the pop off valve opened up and I don't know how long it ran like that but it was getting hot.

When I built my new shop I wired the compressor thru a magnetic starter that is activated with the shop lights. When I walk out the door and turn off the lights power to the compressor is turned off. If I blow a line or some other malfunction when I'm not there it will only empty the tank and not burn up the compressor or worse burn down my shop. A friend of mine lost his shop filled with antique cars and hotrods last summer from a meltdown of a small air compressor.