Cut-40 Plasma cutter

[Karl Robbers]

More expensive, but I have a Lincoln machine that has an internal compressor. However, you could buy an awful lot of compressor for the price difference

Michael

That's true and a beaut little machine she is too.
For a home workshop, I probably wouldn't go that way though because a separate compressor will get used for a great many tasks other than feeding the plasma. Of course you need sufficient power in your workshop to run two 15A devices at the same time.
Those Lincolns are a really nice little site machine though.

[Legion]

Now that I'm onboard with the blue brand I don't know if I could get a red one. None of the blue ones match my requirements. 3 phase would be good and inbuilt compressor until I get a standalone one like I've been meaning too for years.

[BobL]

Talking to my solar engineer BIL about his latest and greatest and he told me he had been experimenting with various Cu and SS finned pipes for his Solar HWS.
I asked him if he had any to spare so he gave me a 7m long, 20mm diam, HD, finned copper pipe that he had recently pulled out of a trial solar HWS.

I was thinking of attaching this between the compressor and the receive to help condense any water.



The pipe istself is rated to 85 bar and is supposed to be 6.5x more effective at conducting heat into out than a regular copper pipe.

[Karl Robbers]

Talking to my solar engineer BIL about his latest and greatest and he told me he had been experimenting with various Cu and SS finned pipes for his Solar HWS.
I asked him if he had any to spare so he gave me a 7m long, 20mm diam, HD, finned copper pipe that he had recently pulled out of a trial solar HWS.

I was thinking of attaching this between the compressor and the receive to help condense any water.



The pipe istself is rated to 85 bar and is supposed to be 6.5x more effective at conducting heat into out than a regular copper pipe.

Go for it! I reckon that would be a brilliant upgrade.
If nothing else, it will cool the air allowing other downstream devices to better separate moisture.

[Karl Robbers]

Now that I'm onboard with the blue brand I don't know if I could get a red one. None of the blue ones match my requirements. 3 phase would be good and inbuilt compressor until I get a standalone one like I've been meaning too for years.

Your post got me thinking. I have never seen a Miller plasma cutter in my travels.
There seems to be only 2 models offered here.

[Legion]

I looked it up. They make a nice one for the US market called the Spectrum 875 with the auto voltage thing that would work on our three phase but we don't get it here. RRP US$3085 which probably means AUD$10000.

[Michael G]

Now that I'm onboard with the blue brand I don't know if I could get a red one.

My blue and red co-exist quite well on the same trolly, although like you I wondered at first. I'd prefer one in blue too, but...

Michael

[soundman]

Talking to my solar engineer BIL about his latest and greatest and he told me he had been experimenting with various Cu and SS finned pipes for his Solar HWS.
I asked him if he had any to spare so he gave me a 7m long, 20mm diam, HD, finned copper pipe that he had recently pulled out of a trial solar HWS.

I was thinking of attaching this between the compressor and the receive to help condense any water.



The pipe istself is rated to 85 bar and is supposed to be 6.5x more effective at conducting heat into out than a regular copper pipe.

I have real concerns with copper pipe and compressed air.

If copper pipe is to be used for compressed air it needs to be the right stuff, in perfect condition and appropraitly terminated....certainly annealed copper pipe should not be used with compressed air.

There is a tremendous amount of energy stored in compressed air systems and in the case of a rupture it is all released at once.

Copper tends to work harden with the constant rises and falls of air pressure....when it fails it can flail around like a sythe.

My additional concerns about the finned pipe in question are that it has been used with water and may be compromised with corrosion and it has bends which may compromise its integrity and may indicate that it is annealed copper.

The option of a second reciever (particularly using some sort of rated fit for purpose pressure vessel) is far easier and safer.

Besides....reduction in temperature of the air is only one part of getting moisture and oil to drop out of the air stream.....the second part is significantly slowing the air speed that means massivly increasing the diameter of the pipe ( by making a tank).

A reasonable way to fabricate a tank is to do what is recommended in some of the spray painting literature...that is to take a section of 4 inch gal pipe ( say 1 meter ish long)threaded both ends, fit end caps & adaptors...then mount that inline with the line comming out of the compressor.

cheers

[Karl Robbers]

I hear what you are saying regarding failure of copper piping, but according to Bob, the stuff is rated to 85 Bar or 1232 Psi, so there is a massive safety margin there even if there has been some corrosion. It may pay to make sure you didn't miss a decimal point there Bob.
I agree that slowing the air down is important, hence the use of secondary air receivers, but if you have the materials at hand the cooling tube cannot hurt.
Your warning regarding pipes flailing around is very pertinent and a reminder that all pipework must be secured and not allowed to wave in the breeze.
A secondary air receiver shouldn't be too hard to acquire with the cheap chinese air compressors sold by lower end retailers failing at an alarming rate. There must be heaps of them in recyclers yards.

[BobL]

I agrees with SM about using ordinary copper pipe which is why I used Galv for the compressed air distribution lines in my shed.

I hear what you are saying regarding failure of copper piping, but according to Bob, the stuff is rated to 85 Bar or 1232 Psi, so there is a massive safety margin there even if there has been some corrosion. It may pay to make sure you didn't miss a decimal point there Bob.

I had to admit I looked twice when I first saw the pressure rating and even checked with my BIL about it.

This is no ordinary copper water pipe. It's Wielland industrial grade chiller/condenser tubing designed specifically for for industrial strength heat transfer and air conditioning systems. It's twice as thick as regular copper water pipe and specifically designed to handle high pressures and it can be bent into very tight coils without compromising the pressure rating.

I agree that slowing the air down is important, hence the use of secondary air receivers, but if you have the materials at hand the cooling tube cannot hurt.
Your warning regarding pipes flailing around is very pertinent and a reminder that all pipework must be secured and not allowed to wave in the breeze.
A secondary air receiver shouldn't be too hard to acquire with the cheap chinese air compressors sold by lower end retailers failing at an alarming rate. There must be heaps of them in recyclers yards.

My problem with using a secondary receiver is my compressor is outside in its own enclosure in a narrow gap between the shed and the fence where nobody except the dogs go. There is no space inside the enclosure for a second receiver. There is also very little room to put it next to the enclsoure where it would be exposed to the weather. However I can install the finned copper pipe up against the wall of the shed and being copper it won't matter if its exposed.

[LordBug]

In case it helps with giving anyone ideas, here's my own little pre-condensor on my air compressor.
The separator can be opened up a pinch so that it lets out a small amount of air w/ captured moisture, whilst the rest goes through to the tank. Has been doing a great job thusfar, I'm pretty chuffed with it.
Haven't run it through a lot of continuous cycles though, the coil does eventually heat up all the way to the separator.

Next on the cards is to consider getting a car aircon drier (new ones are cheap, $10 or so!) to grab any further moisture on the outlet side.
One day I'll run fixed piping around the shed & all the way to the carport, large diameter galv pipe to essentially act as a secondary receiver
compressor.jpg

[Karl Robbers]

One day I'll run fixed piping around the shed & all the way to the carport, large diameter galv pipe to essentially act as a secondary receiver

I would use poly pipe, (NOT AG POLY), as it will require less joints, doesn't rust and is far cheaper.
That is what I will be doing in my shed when I actually have time to do it.

[BobL]

I would use poly pipe, (NOT AG POLY), as it will require less joints, doesn't rust and is far cheaper.
That is what I will be doing in my shed when I actually have time to do it.

One of the most useful thing about galv pipe is you can hang all manner of crap from it.


Some my angle grinders

[soundman]

Well I got the cut 40 fired up today.

a couple of points.

It came with a filter reg and some fittings but no hose.
The fitting on the back of the plasma box is 5/16" and the fittins supplied for the filter reg are 5/16"......not exactly a common air hose.

I went down to the local tool shop..they had a male nito barb fitting in 5/16 but no hose.

So it was off to the local diesel spares shop..they had some gates hose in 5/16 ( wonderfull stuff pressure, heat and fuel rated).


I got it all together and fired up but it was a bit flakey....I had a good look at the torch and there where some moulding dags just above the thread where the outer ceramic scres on and the O ring is suposed to seal....I few strokes of a file and that was all solved.

The trigger connection a 2 pin CB microphone type plug.....has been terminated with the outer insulation a bit short and it is not clamped in the strain relief.....I'll reterminate that properly in due course.

appart from that it seems to be pretty damn fine.....still getting a handle on the current v thickness thing....but it cuts fine.

Using a straight edge to run the torch up against is the go if you want anything like a straight cut.....and doing this you can get a pretty clean straight cut.

Plasma cutter for $300 bucks...HELL YEH

cheers

[Karl Robbers]

As a generalisation, you will find that more amps is better than less. For example, on my machine 60 amps will cut 5mm steel plate very nicely, but 90A absolutely cuts like Luke Skywalkers light saber, faster and cut quality very near laser quality. You definitely would be needing a straight edge to track accurately at the speeds it produces.
What I am really saying is that there is a lot of wiggle room, so don't be too concerned at getting amps just right.