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.