Cut-40 Plasma cutter

[beefy]

Just to reinforce what Karl said about clean dry air. I've built my own CNC plasma table and have a Powermax 1250 cutter with the revered Duramax torch retrofit. This is what I did to give me dry air:

Took a 4 foot high LPG tank and buried it in the ground vertically. It has a small line comes off the bottom and the amount of moisture (i.e. pool of water) I bleed from that is evidence of how much is in your compressed air. The ground is always cool even in summer so the tank is a great initial condenser stage.

Next the air goes to a DIY refrigerated air dryer. I took a window AC unit and put it inside a closed loop wooden enclosure that also houses a condenser and evaporator from a car AC system. These are rated to a good pressure and I pass the compressed air through them. The air outlet goes into a basic water trap.

Next the air goes to another DIY contraption, a tank filled with the fillings of diapers LOL. There's a lot of good dessicant in those diaper fillings.

Finally it goes through a small commercial quality filter, just in case any fibres from the diaper dessicant get pulled loose.

Point is take moisture removal seriously. Better cut quality, much longer consumable life, lower cut cost.

Keith.

[soundman]

Beefy mate... bit of over kill ..... as I have posted a few times in the past, simply installing a second reciever after the main tank in any compressed air system will drop a hell of a lot of moisture out of the system.

I have a relativly small tank ( bout same as on the compressor) that sits next to my compressor connected by about 2 meters of hose, then go thru my main filter reg and into my pipe system ...... for spraying and plasma cutting I go thru a second filter reg.

I get ver little water in my main filter reg ..... I empty it every couple of months.

I have never seen any water in my second reg.... not even a spot of condensation.

The only time I have ever seen any moisture out of my system was after a heavy and prolonged session ( several days) of sand blasting, when my main filter reg had become overloaded.

I have two mates that have set up similar arrangemsnt and they recount similar reports.

cheers

[Vernonv]

That does sound like very serious overkill (certainly for the average user).

I've just finished a job that involved a hell of a lot of cutting (close to 100 lineal metres worth) and simply had a large compressor connected to a smaller compressor (for extra storage only) and a standard water trap at each end of the 10m hose - got the tiniest bit of water in the first water trap (I have a feeling that may have already been in there before I started) and none in the second.

I think for the average user it's a bit of a non-issue.

[Legion]

For my water trap I bought a ~10m copper tube, coiled it up and stuck it in an 11L bucket, one of those white plastic ones the same build as the white 20L but half size. On one end I have a male nitto. On the other it connects to a La Man 105 and off that I have a female Nitto. The extractor sits in the middle of the bucket in the middle of the tube on a little stand I made from ally plate offcuts. I fill the bucket with tap water so the air gets well cooled by the water by the time it gets to the extractor and the extractor filters it out. A fair amount of water comes out, but I attach my compressor with only a couple of metres of hose (compressor has a filter/regulator on it already but just a cheap chinese one, not as good as the La Man). If I really wanted to condense out more I would tip a tub of ice in the bucket too but for painting the air comes out dry as a desert, it seems. My compressor is semi-portable and therefore I wanted a portable drier too and the bucket/copper/extractor fits the bill.

[BigPete1]

Hi, I bought one of these Cut-40 plasma cutters. Works reasonably well for a cheap machine. Could someone tell me the correct air pressure required. The manual is completely useless. Also I'm getting a fair amount of dross, which is not real easy to remove. Is this because its a cheap machine? Or is it user error? Thanks Pete.

[beefy]

Beefy mate... bit of over kill ..... as I have posted a few times in the past, simply installing a second reciever after the main tank in any compressed air system will drop a hell of a lot of moisture out of the system.

I have a relativly small tank ( bout same as on the compressor) that sits next to my compressor connected by about 2 meters of hose, then go thru my main filter reg and into my pipe system ...... for spraying and plasma cutting I go thru a second filter reg.

I get ver little water in my main filter reg ..... I empty it every couple of months.

I have never seen any water in my second reg.... not even a spot of condensation.

The only time I have ever seen any moisture out of my system was after a heavy and prolonged session ( several days) of sand blasting, when my main filter reg had become overloaded.

I have two mates that have set up similar arrangemsnt and they recount similar reports.

cheers

Yep, overkill for an average user with a hand torch, NOT overkill for a CNC plasma table running 85 amp nozzles and a 5 hp compressor going just about flat out. I was not suggesting members should do the same setup, I was just telling what I did to get very dry air, and I said the point is to take moisture removal seriously.

Many of the guys with CNC plasmas have refrigerated air driers and a filter downstream of that. I've had cuts that last 30 minutes without a break, and they could easily get longer with tightly nested parts. I don't rely on just a condensation tank to get the moisture right down. Compression produces a lot of heat so with time the condensing effect of the receiver may diminish. On a long cut you want maximum life out of a nozzle so the cut is not halted in the middle. If the first stage (condensation tank) can't keep up, the low temperature of the refrigerated air dryer gets it. Not only that but the lower the dew point the more moisture is condensed out of the air, so air going through a refrigerated air dryer is going to be drier than air going through a condensation system alone. The machine torch alone cost me $1100 so I'm more than happy to have very dry air going through it.

I researched first then based my system on what many were doing with cnc plasma tables and in industry in general. Maybe they are all wrong and nothing but a condensation tank is needed.

Keith.

[RustyArc]

Hi, I bought one of these Cut-40 plasma cutters. Works reasonably well for a cheap machine. Could someone tell me the correct air pressure required. The manual is completely useless. Also I'm getting a fair amount of dross, which is not real easy to remove. Is this because its a cheap machine? Or is it user error? Thanks Pete.

My Cut-40 manual says 4.5 Bar.

I too get tough dross, but I probably need to do a bit more work with it to find out if it's a function of amps, travel speed or air pressure.

[BigPete1]

My Cut-40 manual says 4.5 Bar.

I too get tough dross, but I probably need to do a bit more work with it to find out if it's a function of amps, travel speed or air pressure.

Thanks Rusty

[Karl Robbers]

Yep, overkill for an average user with a hand torch, NOT overkill for a CNC plasma table running 85 amp nozzles and a 5 hp compressor going just about flat out. I was not suggesting members should do the same setup, I was just telling what I did to get very dry air, and I said the point is to take moisture removal seriously.

Many of the guys with CNC plasmas have refrigerated air driers and a filter downstream of that. I've had cuts that last 30 minutes without a break, and they could easily get longer with tightly nested parts. I don't rely on just a condensation tank to get the moisture right down. Compression produces a lot of heat so with time the condensing effect of the receiver may diminish. On a long cut you want maximum life out of a nozzle so the cut is not halted in the middle. If the first stage (condensation tank) can't keep up, the low temperature of the refrigerated air dryer gets it. Not only that but the lower the dew point the more moisture is condensed out of the air, so air going through a refrigerated air dryer is going to be drier than air going through a condensation system alone. The machine torch alone cost me $1100 so I'm more than happy to have very dry air going through it.

I researched first then based my system on what many were doing with cnc plasma tables and in industry in general. Maybe they are all wrong and nothing but a condensation tank is needed.

Keith.

No such thing as overkill when running a plasma cutter and chasing quality cuts. I was once advised to run the same level of filtration for a plasma as you would for breathing air. From my personal use of plasma cutters, I reckon that can only be a good thing.
For sure, you can get by with far less, but cut quality and tip life will suffer.
The Lincoln PC 100 plasma that my last workplace had was lucky to get 1M of quality cut from a tip and electrode due to oil and water contamination, while the same machine and torch, used for stripping backing material by a local bearing manufacturer was achieving 2-300M of quality cut with no visible damage to either tip or electrode. The only difference was the air supply.

[Karl Robbers]

My Cut-40 manual says 4.5 Bar.

I too get tough dross, but I probably need to do a bit more work with it to find out if it's a function of amps, travel speed or air pressure.

Yes, yes and yes, with the addition of dirty parent metal as a possible cause, assuming of course that your tip is not worn out.

[Vernonv]

The Lincoln PC 100 plasma that my last workplace had was lucky to get 1M of quality cut from a tip and electrode due to oil and water contamination....

Wow, that is very poor. As I said I did close to 100m of freehand/template cutting and am on my second tip and third electrode. And the only reason I changed tips/electrodes that often was to maintain cut quality, as I was cutting holes in posts to slide cattle rail into ... and it had to look neat. Tips and electrodes are cheap as chips anyway.

I guess my take on it is that for the average user​ (i.e. non-CNC user) don't get too caught up in producing air of the highest purity as it's a waste of time, money and often portability.

[beefy]

I too get tough dross, but I probably need to do a bit more work with it to find out if it's a function of amps, travel speed or air pressure.

Generally, tough dross is caused by too high a travel speed. I tend to think of it as molten metal is blown out but doesn't have time to get fried to a crisp. It normally gets called "high speed dross" and is more like weld beads than dross.

When the speed is too low you get "low speed dross" but that chips off quite easily. I tend to think of that as molten metal that got fried to a crisp (the lower speed "fried" it for longer) and just crumbles.

With a quality torch, clean air, etc you can find that middle ground where you get zero or very little dross, but with a hand torch that's completely relying on the skill of the operator to maintain correct height and travel speed, not an easy task. As a matter of fact that's what pushed me to start learning about cnc. I got the a zillion times when doing oxy cutting and realised I needed a lot more skill to get good cuts.

Keith.

[Karl Robbers]

Wow, that is very poor. As I said I did close to 100m of freehand/template cutting and am on my second tip and third electrode. And the only reason I changed tips/electrodes that often was to maintain cut quality, as I was cutting holes in posts to slide cattle rail into ... and it had to look neat. Tips and electrodes are cheap as chips anyway.

I guess my take on it is that for the average user​ (i.e. non-CNC user) don't get too caught up in producing air off the highest purity as it's a waste of time, money and often portability.

The poor old compressor had seen better days and the oil had to be filled up - not just topped up, twice weekly.
Of course, you know where the oil ended up and in the 20,000 degree plasma stream it decomposed explosively and destroyed electrodes and tips.

[Vernonv]

Sounds like your due for a new compressor there Karl.

[Karl Robbers]

Sounds like your due for a new compressor there Karl.

Yes, the old Servex had done a lot of work with no thanks and little maintenance. It's still pumping away filling the lines with sludge to this very day I believe.