# Plasma Cutter



## Anonymous (Nov 8, 2009)

Recently purchased a Cut-70 amp plasma cutter from a Chinese ebay vendor - 6 days delivery time, after using this for a couple of days kicking myself in the butt for not buying one sooner.

This new IGBT and Pilot arc technology is great, I have put this machine through it paces , cutting through some black iron gas pipe with the plastic coating, painted metal, heavy brass tubing and some heavy wall stainless steel pipe I had kicking about.

Cut up a Ford Ranger into small enough pieces that I could hall the body and frame off to the scrap yard, and I'm still on my first tip aka consumables.

Really didn't need a 70 amp machine a 50 amp woulod have done but went larger to up the duty cycle for the 1/4" to 1/2" if I decide to cut a lot of material then I'm not going to abuse the machine with lots of amps in reserve.

On receiving the machine the air regulator and dryer had to be attached, the holes were way to small for the screws provided, so I removed the cover to see what if anything I would be drilling into enlarging the holes. 

Here's what I found inside, copper windings used on all the transformers, copper wire used in the circuits and HUGE heat sinks used where required.

Would I buy another? Yes


----------



## markqf1 (Nov 8, 2009)

8) 
Sounds like it would be great for decanning converters.

Mark


----------



## Anonymous (Nov 8, 2009)

markqf1 said:


> 8)
> Sounds like it would be great for decanning converters.
> 
> Mark



Yes I decanted several, from experience found it best to direct the plasma stream downwards just inside the seam of the can otherwise the plasma will burn into the honeycomb. 

The plasma arc travels through the nozzle at a speeds of up to 20,000 feet per second, and at temperatures as high as 30,000 degrees Fahrenheit (16,600 Celsius)!


----------



## Anonymous (Nov 8, 2009)

they are great for cutting stainless, you are a lucky man to have one. 

jim


----------



## LeftyTheBandit (Nov 8, 2009)

May we ask how much such a unit cost?


----------



## Anonymous (Nov 9, 2009)

LeftyTheBandit said:


> May we ask how much such a unit cost?



The Cut-70 cost $598.00 with $150.00 DHL air, 6 days to my door. if your going to purchase one get one with IGBT technology, High frequency no contact start and Pilot arc start for those wishing to use this machine on a cnc table.

The machine I purchased http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400065912346

Don't waste your money on the plasma cutters using MOSFET inverters.


Article on IGBT invertoers http://www.sea.siemens.com/us/Industry_Solutions/Mining/mining-solutions/Pages/Shovels.aspx


----------



## scrapdealer (Nov 11, 2009)

Sounds like a super piece of kit, I got to have one. 
Any photos of one in action.? Can it cut thick profile Copper or Aluminium.
What consumables are needed.?
- Peter


----------



## patnor1011 (Nov 11, 2009)

scrapdealer said:


> Sounds like a super piece of kit, I got to have one.
> Any photos of one in action.? Can it cut thick profile Copper or Aluminium.
> What consumables are needed.?
> - Peter



we have one, i can only recommend that. i dont have any video of it in action but youtube is your friend tons of it there:
http://www.youtube.com/results?search_query=plasma+cutter+demo&search_type=&aq=8&oq=plasma+cutt


----------



## Anonymous (Nov 11, 2009)

scrapdealer said:


> Sounds like a super piece of kit, I got to have one.
> Any photos of one in action.? Can it cut thick profile Copper or Aluminium.
> What consumables are needed.?
> - Peter



The plasma cutter will go through any metal you throw at it, for instance my 70 amp will cut 28mm thickness with a clean cut, a severance cut will be much thicker bit not very pretty

I have cut miles and miles of steel cable from 3 inches in diameter down using an acetylene torch and this sucks big time, the plasma cutter zips right through - no pre heating required. Wished I had this thing when I was in the scrap business. 

Consumables consist of a ceramic cone, a tip and nozzle, I don;t think that you have to change the whole kit every time, if your cutting scrap and not getting fussy about your finished cut you'll get some millage out of your consumables. So far I have cut 12 catalytic's, one ford ranger into manageable pieces, trimmed some stainless steel plate, and some titanium pipe I had laying about and cut some heavy brass pipe, some copper pipe and half dozen crushed computer cases to get the goods out and a couple of bicycles for the shaker table I'm building. And I'm still on my first set of consumables.

Theres a trick to piercing through metal, you angle the torch head in a way so that the molten metal does not blow back into the tip. If you have ever tried to pierce through using a cutting torch your going to love your new plasma cutter. The hole is instantaneous, no pre heating. 

Almost forgot, the front bumper from the ford ranger is chrome plated, and I cut it into a zillion pieces, all my starts were pierced through, the cut was a fine line with no warp-age or discoloration to the chrome in the cut zone.

As the nozzle wears the hole gets larger the width of the cut gets wider and the depth ( thickness of metal ) of the cut decreases. Just install a new nozzle to bring your plasma torch back up to snuff. 

Then the other evening I had to use my oxygen/acetylene outfit to heat and bend a piece of brass into a handle and forgot to turn the bottles off, now I'm almost on empty. I;m going to cancel the contract and use an old carbon arch torch I have for those jobs that require heating. 

If your going to purchase a plasma cutter get one with the IGBT inverter, it's not really important who manufactured the inverter it's being manufactured under license from Siemens

Consumable - 90 pieces for $75.00 free shipping, less than the cost of one small bottle of oxygen 
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170269020605&ssPageName=STRK:MEWNX:IT


----------



## Anonymous (Nov 12, 2009)

Ok, my Cut-70 will cut 28mm as advertised but should be considered a severance cut, maybe it's time to install a new nozzle.

From the attached pictures you can observe that the plasma will cut more than just metals. First picture is a solid carbon rod 1 1/2" diameter, then the Catalytic honey comb just to give you an idea of how hot the plasma is.


----------



## Anonymous (Nov 12, 2009)

I inquired from the seller the plasma cutter about the price increase, if your thinking about making a purchase go to his UK ebay store for the lower pricing.

Dear gustavus1,

We are highly appreciated for your affirmation us. someone USA ebay seller object the low price to manufacturer.but
our UK ebay shop the price have not change.the shipping cost USA and Canada buyer is lower than UK buyer.
sorry for any inconvenience causing.
regards.


----------



## Irons (Nov 12, 2009)

Be careful when cutting materials such as Stainless. The 'smoke' can be quite toxic. Chromium, Nickel and other oxides are not good for long-term health.


----------



## Anonymous (May 14, 2010)

Finally had a problem with my Chinese Plasma cutter, you would never believe the support I have been receiving from the vendor located in Hong Kong. After determining the torch was at fault he is sending a replacement at no cost. Can't complain about that for service.

Best Regards
Gill


----------



## jimdoc (May 14, 2010)

Gill,
Thats good to hear, sounds like a company that wants to stay in business and keep a good name for themselves.Hard to find that anymore. 

Jim


----------



## chemist (May 14, 2010)

Can you use the plasma cutter to melt gold powder?


----------



## patnor1011 (May 14, 2010)

chemist said:


> Can you use the plasma cutter to melt gold powder?



no


----------



## LeftyTheBandit (May 15, 2010)

Can you use plasma cutters to incinerate a flow of waste passing through the plasma field?

I have heard of plasma arc furnaces, and they are interesting and might be a good experiment to treat eWaste. I have read on Wikipedia that the technology is used in Japan to treat municipal waste.

I was thinking of 3 torches going and running a flow of ground eDust through the plasma field. The heat of the plasma field is in the 5000deg range so all molecules get obliterated into elements. You are left with metal dore and a slag of carbon wool. This wool is lighter than water so it floats and can be used to soak up oil spills on the ocean. The dore goes to a copper refinery.

Back to reality....


----------



## patnor1011 (May 15, 2010)

this plasma cutters are working on different principle. they like welding machine needs to make contact to metal with one lead.


----------



## Anonymous (May 15, 2010)

patnor1011 said:


> this plasma cutters are working on different principle. they like welding machine needs to make contact to metal with one lead.



Your wrong on that one partnor1011, the plasma cutter I have will spit a stream of plasma with out being in contact with the conductor. Most of the new plasma machines have High Frequency non contact start, these new machines are a great candidate for CNC cutting tables.

Great for cutting expanded mesh because the plasma stream is constant. In an earlier post i had a picture of some catalytic comb and a 1 1/2" carbon rod I had cut. The plasma stream is closer to 10,000 deg.


Best Regards
Gill


----------



## AKDan (May 15, 2010)

Gill, 
You mean to say that there is not any sort of ground lead on your machine that needs to be connected to the part being operated on? If so, I have never run into that yet.


----------



## Anonymous (May 15, 2010)

AKDan said:


> Gill,
> You mean to say that there is not any sort of ground lead on your machine that needs to be connected to the part being operated on? If so, I have never run into that yet.



All you have to do is pull the trigger to excite the plasma stream, it will cut with out the ground clamp being hooked up but not a very nice looking cut. Truth be know this is probably how I screwed up the torch head. The electrode aka consumable was at its life end and I had a blow out inside the torch head which burned some of the seat away.

The electrode has swirls built in to vortex the incoming air into the plasma stream.

I was cutting up an old truck into manageable pieces and where the wiring harness and that huge bundle of wires connects at the firewall used the plasma stream to burn through the bundle a practice I will cease..

The technology behind the HF non contact start of the plasma stream is for primary use on CNC cutting tables or when you have to cut expanded metal, heavy wire mesh, painted metal or that which is coated heavy oxide or rust scale such as metal found on old ships and shipyards.

It definitely cuts better with the ground clamp connected.

If the machine was totally toasted I would have purchased another in a heart beat, you can open a catalytic in no time. Once you learn where not to cut into the can your not getting into the comb.

Best Regards
Gill



.


----------



## skippy (May 15, 2010)

Gill, so when you make the cut without the ground cable the plasma can damage the gun? Is that basically it? Hopefully the rest of us can learn from your example. I'm hoping to buy a plasma cutter myself in the near future.


----------



## Anonymous (May 15, 2010)

skippy said:


> Gill, so when you make the cut without the ground cable the plasma can damage the gun? Is that basically it? Hopefully the rest of us can learn from your example. I'm hoping to buy a plasma cutter myself in the near future.




Yes extended use of the HF Pilot Arc start with or with out grounding will damage the torch, by this I mean that if you were cutting expanded metal mesh you would be passing the plasma stream through open space where the grounding clamp would be of no use. So you would want to cover that open gap fairly quickly.

Don't be an idiot like me and stand there trying to arc your way through a bundle of insulated wires.

If your contemplating the purchase of a plasma forget about the MOSFET get one that has IGBT, if you think a 40 amp machine is going to do the job for you get a 60 amp machine. The greater the amperage the greater the duty cycle is going to be at 40 amps giving you a margin of safety from having to watch your machine go up in a puff of smoke.

Often a person will buy the machine on advertised specs, machine will cut 1/2" steel plate and all are happy. Making a short cut would not tax the machine with short rest periods between cuts on a 40 amp machine the 60 amp would consider 1/2" plate butter because it is rated for 1" steel plate and could cut 1/2" plate for hours on end.


The air regulator with water separator that came with the plasma cutter seems to do a good job of keeping the moisture out, you need a good sized compressor to run the cutter. I have a 5 hp Devilbiss on a 80 gallon tank and it runs almost constant when cutting some of the heavier metals.

Best Regards
Gill.



.


----------



## AKDan (May 15, 2010)

Guess I just never thought to try it without the ground clamp on the material I was cutting. The unit I have has the high frequency no touch start, like a TIG machine, and like TIG can be set to momentary or continuous. Even on momentary while cutting something like expanded metal, or chain link, with the ground clamp connected you can see the plasma exiting the tip when off the metal. With all the years of using torches I don't know how I could ever go back after using plasma, other than the extras that are needed such as electricity, air, etc... The unit I have plugs into my Miller 302 though and so power is never an issue, unless I am out of fuel  Just have to keep the compressor handy.


----------

