Plasma Cutter

I recently bought a Chinese 40 amp. plasma cutter. The "manual" is pretty rudimentary. I have never owned a plasma cutter and I have a couple of questions about operating one.
The manual specified air pressure is 4.5 Kg/Cm - about 65 PSI. Does one vary the air pressure depending on the thickness of the material being cut? The machine has an ON/OFF Switch, an Amperage Control Dial 0 - 40 A and an additional switch, not mentioned the manual, marked "2.5 SS" and 5.0 SS". Does anyone know what this switch might be?
Bruce in Bangkok (brucepaigeatgmaildotcom)
Reply to
Bruce
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Further to my previous post. The welder is a Riland Plasma "Cut-40". I have googled Riland USA and downloaded the operating manual, which is a copy of the original "English Language" manual that has been edited into English.
However, the Riland USA manual still doesn't show the switch I mentioned. It isn't logical that the switch is any kind of a "range switch" as the amperage control covers the cutter's entire range and the only other thing I can think of that might be controllable is the air flow timing although that seems redundant, but maybe not.
Any help will be greatly appreciated.
Bruce in Bangkok (brucepaigeatgmaildotcom)
Reply to
Bruce
I recently bought a Chinese 40 amp. plasma cutter. The "manual" is
pretty rudimentary. I have never owned a plasma cutter and I have a
couple of questions about operating one.
The manual specified air pressure is 4.5 Kg/Cm - about 65 PSI. Does
one vary the air pressure depending on the thickness of the material
being cut?

The machine has an ON/OFF Switch, an Amperage Control Dial 0 - 40 A
and an additional switch, not mentioned the manual, marked "2.5 SS"
and 5.0 SS". Does anyone know what this switch might be?
Bruce in Bangkok
(brucepaigeatgmaildotcom)
Reply to
Bruce
The air pressure used stays at the same pressure for all cuts regardless of thickness. May want to vary it up somewhat to decide what the best pressure is. I run at 70 PSI. The 2.5 SS and the 5.0 SS switch allows the air to flow from the nozzel for that many seconds after the trigger is released. Enjoy!
Reply to
RJ
Many thanks for the quick answer.
But why vary the length of time the air flow continues? My understanding was that the consumables didn't get that hot. Wrong?
Bruce in Bangkok (brucepaigeatgmaildotcom)
Reply to
Bruce
I feel a bit stupid. I went back to the shop this morning and sure enough the switch is for the post air delay. (Why didn't I think of that?)
Adjusted the air pressure to 4.5 Kg./Cm2 and Lo, it cuts like a champ.
Thanks to all that replied.
Bruce in Bangkok (brucepaigeatgmaildotcom)
Reply to
Bruce
Bruce, could you keep us posted on this machine please? I'm looking at the combined TIG/Arc/Plasma cutter from China (CT-130 IIRC) They're a lot cheaper than anything I could buy here in the UK. Yeah, I know cheap isn't usually good ecconomy but I will only require it for hobby use. First main project will be making equal length headers for my Subaru powered VW camper van :)
Cheers
Reply to
Balders
I bought a Riland CUT- 40 in Singapore. It is a straight 220 VAC, single phase, machine.
Riland USA, apparently a U.S.A. agent, has a good site, I believe
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with re-translated manuals. The original Chinese translations do leave a bit to be desired :-{
As I have been told that running air with appreciable water content through a Plasma cutter is not good I added a "pre-filter" to the machine by installing a small water seperator/filter to the inlet of the existing filter/pressure regulator. To add the new filter I had to drill two holes in the back of the cutter to attach a mounting bracket for the filter and prior to drilling any holes in my brand new cutter I removed the cover.
I am a fairly competent electronics guy (US Government radio maintenance license holder) and in my opinion the construction of the solid state circuit board in the machine is very good. All components look to be good quality and the C.B.'s all look like quality construction.
When I purchased the cutter I asked that we test it before I carried it off. This is a very normal practice in most of Asia, in fact , when buying an electric light bulb, the shop usually tests it without being asked.
The shop took the cutter and me to their maintenance section where we tested it. The shop sells several brands of welding machines and has one technician to rebuild/repair machines. I asked him about "how many of these cutters have you repaired?" He said that they did get a few back for repairs but not many.
How does it work?
Well, after I got the air pressure set correctly I made test cuts in 1/8" aluminum, 1/8" stainless and 3/8" stainless. All materials were cut easily and for the 3/8" stuff I had the amp control set to less the 50% of the maximum 40 amps.
I haven't tried 1/2" material yet but from all indications it should cut 1/2" stuff easily. The cut finish on the 3/8" stuff was normal cut quality, not the ragged "sever" cut that is the absolute maximum that the machine can do.
The machine was wired through a 15 amp, 220 VAC, single phase, breaker and cuts up to 3/8" with no problems.
I've got a bunch of stuff to build for this boat I'm rebuilding and will report on any problems I encounter.
A last comment on Chinese made goods.
They range from pretty awful to not bad at all. I bought a toaster (Baht 99, about US$ 2.75). It toasted only the outer side of each slice of bread. I ran a pipeline project using Chinese made diesel driven welding machines. We completed some 50 Km. of 4 and 7 inch xrayed gas pipeline with no machine failures.

Bruce in Bangkok (brucepaigeatgmaildotcom)
Reply to
Bruce
Thanks for that. I know Chinese stuff regulary gets slated - but my budget isn't much.
Here's the link to the sort of machine I'm thinking about:
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Any comments would be much appreciated.
Reply to
Balders
I had a look at the site you mention and then googled it. There don't seem to be many places that welder is sold and I'd want to know whether I could get it repaired as it appears to be shipped from China.
These things are really electronic welding machines and are crammed with printed circuit boards. Most of the components appear to be standard electronic parts but there are a couple of gizmos in there that aren't standard devices.
The other question is what kind of cutting torch does it have and are consumables available? Probably the answer is yes, but it would be well to check. The TIG torch is less of a problem as they are pretty standard and don't burn out if you use then as they are meant to be used.
If you TIG weld you will need an argon regulator as I didn't see one as part of the package.
Bruce in Bangkok (brucepaigeatgmaildotcom)
Reply to
Bruce
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Hi, It's not my business, but i bought a plasma cutter from River. She's very nice (she's a girl), and did me a discount. You can contact her on MSN (in the morning ,european time) I'm pretty sure you can get a discount too.. Good luck Rob
Reply to
zorro
I just bought myself a L & Lee International "Cut-50" My guess is that it's all the same machine, they just put whatever name badge is required onto the box.
It's pretty basic, but did come with a water separator/filter and 3 sets of consumables.
It's been cutting through all sorts of stuff, does pretty well on 10mm steel, and it goes through 2.5mm alloy like it's not there.
It's cheap and cheerful and hardly in the same league as Miller or TD, but it was 25% of their price ! And it's not like my livelihood depends on it. And it's got a year warranty.
I'm going to pull it to bits one day and take a look at the quality, etc inside. Right now, I've only had it 3 hours.
Barry
Reply to
Barry Lennox
Thanks for the replies chaps. I will certainly think about getting one & will keep you posted if I do. As I say it'll only be for light auto use: another Bug resto & some SS header pipes (Hell this thing's cheaper than a reasonable set of headers, which I'd have to modify anway!)
Appologies for the hi-jack.
Reply to
Balders

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