Cheap Plasma Cutters?

[vtsteam]

Anybody tried any of the  < $200 plasma cutters ( £ 150) ? I see a large number of seeming clones on Ebay and Amazon. If you have one, what's your experience? I've seen a couple YouTube vids, but wondered if I might hear from a real person about theirs.

btw, I already have a couple of cutting torches: acety and propane. Mainly interested in it for sheet metal cutting, and the small size of these units is appealing for the space I have available. Location flexibility of occasional 110v for thinner stuff is appealing. 220 otherwise. And the price also makes them a possibility.

[Sea.dog]

I have a 30A one bought from LIDL ( a German supermarket chain) for £80. It works very well. In fact, it's a 40A machine but down-rated because of our plugs, which have to be fitted from the factory. Fit a 16A plug, tweak a pot and the job's done.

[Pete.]

Graham where are the instructions on tweaking the 30a units to 40a? Reliable ones I mean?

I've been playing with a 100A one for the last couple of days, blasting through 25mm steel.

[Sea.dog]

Hi Pete, there aren't any. However, if you look at the post on MigWelding, I did look inside mine and determined which of the pots need tweaking but, at the time I A). didn't have a suitable compressor and B). didn't have a DC clamp meter, so didn't try it myself. The original OP did and I believe that it worked OK.

Here it is - https://www.mig-welding.co.uk/forum/threads/lidl-parkside-30a-plasma-uk-13-02-2020.98311/page-6

My post is No. 114

[RodW]

Personally, I will never buy a no name brand again. Stick to Hypertherm, Thermal Dynamics and ESAB. For hand use a cheap one may be ok but if you are considering CNC control, forget it!

[Sea.dog]

£80 for a cutter with a three year warranty isn't a bad buy. Quite a few members on my other forum have them and are very happy with the way that they perform.

[vtsteam]

Hi Rod, I wouldn't be considering plasma cutting at all if the cost was more than a couple hundred bucks. So it's not a matter of choosing a better brand.

My question is whether it's better to do without or spend that couple hundred. So far it looks useful to me. I do plan on hand use, don't ever cut anything over 1/2" -- much more often cutting 1/8" sheet metal, and have conventional torches for thick stuff anyway. Also hand grinder and metal cutting bandsaw.

It looks to me like for occasional on-the-spot cutting of reasonably thin stock it could be quite handy to have, and its small footprint in a shop, high portability and the possibility of using 110v conventional outlets (as well as 220V) are attractive.

But what I'd like to hear about from you is what were the problems you experienced with yours, what brand was it, was your reason for purchase it CNC rather than hand use, etc. In other words details. If you have time to elaborate that is. Thanks!

[vtsteam]

Seadog thanks for your info, btw. 

If I do get one the next question is which one to get. There are many different brands, and I don't think they are all exactly like. Other than the internals, I'm noticing that they seem to vary in what is included.

I see at least two different torch types. One has the trigger on the bottom with safety, and is a unified blue or orange plastic handle. Another has a thinner two piece black plastic handle with the trigger on top, the top trigger is just a plastic switch zip-tied on.

Also, for the dual 110v-220v types I'm looking at, some come with a short adapter cord for plugging into either type US outlet as needed. Most do not, and only have a 220v  plug on the end of the unit cord. Some have no plug at all and you have to purchase one. If you have to buy a plug, and also make up an adapter cord, you could easily spend an additional $30 here in the US. Plus the waste of time chasing down parts and assembling.

Also, they vary in how much expendanbles are included. Some package 3 of each type, some 5.

A very few of these plasma units are barebones -- only the torch and plasma unit in the box. You have to carefully read the description to know exactly what you're getting in all of these.

Then there's the output rating -- 30 to 50 (55?) which seems roughly related to the title "Cut__". But not necessarily.

ALL of these units are priced between 180 and 200 US. So, the question is, besides whether to buy one, which brand and from whom? Amazon and Ebay have the most for online purchase (and I'm not going out shopping these days with the Covid numbers as they are). But it seems like there must be a dozen brands at least.

[vtsteam]

One other question to all.

I read open circuit voltage is roughly 100 v -- I assume that's at the torch. If so, and if they tend to rate the 110V input mode as producing 30-37 amps at the torch, how is that possible on a normal 15 or 20A 110 volt outlet? Unless there's a big voltage drop on pulling the trigger. And if that's the case why specify open circuit voltage?

I mean if it was 50V and 30A at the torch, and you were using a 110V 20A outlet, and it was a very efficient inverter, I'd say that is possible. That's 1500 watts out of a 2200 watt supply.

But I don't understand how the figures given add up for 3700 watts out of that same supply....

[awemawson]

Steve, I've been blown away by the versatility of my CNC Plasma table. So many things that frankly previously I wouldn't have attempted are now SO easy.

Silly things like profiling a sheet of steel to be bent into a box or other form - I can virtually go fom a CAD drawing to the finished article and no marking out etc. And if the design needs tweaking, a tweak and do it again !

For years I've had a hand held plasma (Hypertherm Powermax 900) and it only got used very occasionally (can't draw a straight line!), but now the CNC with a Hypertherm  45 is a frequently used tool.

[vtsteam]

That's great Andrew, but no room or money for that.

I'd love to get away from clanking tanks around rough ground in a cart and using lots of extra oxygen just for cutting dimensional stuff. Plus the gas torch setup, Finding the damn striker and lighting, adjusting, then the shutdown of each gas, purging the regulators, wasting more gas, etc etc. It's a big waste of time and materials if you only have one cut to make for a project. Or want to burn off a bolt, a piece of rebar, etc. It would be nice to just flip a switch and cut something, as and when needed. And I also think hand cutting curves in sheet stock will be easier than with my propane cutting torch. It's gotta be more economical. I dunno, haven't ever tried with plasma, so I can't compare.

[awemawson]

Why not hire one for a weekend and see how you get on. Then you can make decisions from your own experience.

[vtsteam]

Andrew I doubt anybody in our area rents out $200 plasma cutters, and even if they did, we're minimizing contact these days.

After much poring over details I've decided to take a chance on a factory refurbed Amico CUT50 with 1 yr warranty. Costs about the same as the numerous other new cheap odd branded models on ebay.

I liked the specs better, included adapter cord, and the AG60 torch included compared to some of the others. Could be a mistake, but what the heck. Will arrive couple days after my birthday. One hopes.......

[howsitwork?]

Steve and as it’s a birthday present it don’t count Good luck

learned that one years ago.

Happy Mew Year, let us know how much fun it is please?

I’ve just been playing with my cheap MIG making a couple of new rests for the wood lathe. I won’t win any prizes for the welding but not had any practice this year and penetration was good ( read that as scorched the bench underneath)

[awemawson]

Happy Birthday Steve,

What’s it like to be 21, remind me 😀

[RodW]

Hi Rod, I wouldn't be considering plasma cutting at all if the cost was more than a couple hundred bucks. So it's not a matter of choosing a better brand.

But what I'd like to hear about from you is what were the problems you experienced with yours, what brand was it, was your reason for purchase it CNC rather than hand use, etc. In other words details. If you have time to elaborate that is. Thanks!

Well I had a BOC 40 amp plasma cutter and  decided to CNC it but it died before it did. An electronics guru I know attempted to repair another Cut40 one which then let out smoke in the most spectacular fashion. So I bought an Everlast (Rtech in the UK). It had a few issues so I sold it. I now have a 120 amp Thermal Dynamics on my table.

As Awemawson says, they are actually incredibly useful. So much so I bought a CNC press brake to go with the plasma table I made. You could build a small CNC table fairly cheaply using belt drive and Linucxcnc's Plasmac config.

If you cheap out on the plasma cutter, be sure to get one with a blowback style torch and avoid the High frequency start ones. They use about 25000 volts to start the arc which is not a pretty sight if you get the electronics wrong!

There is a Herocut 55 on Amazon which has blowback start and also includes Torch on inputs, Arc OK and raw arc voltage outputs. I have seen some reports of them not lasting either but it might be a good place to start for a cheap CNC machine.

The thing you get with the brands I listed earlier are cutting charts (a lot of them at 120 amps) so they save a lot of material, time, money and effort.....

An old PC with parallel port, a BOB,a USD $69 Mesa THCAD-10 board to read arc voltage will fix the electronics but you will get a much better machine with a $119 Mesa 7i96 ethernet board instead of the parallel port BOB.  This lets you use something like an Odroid H2+ PC which is now my system of choice for Linuxcnc and Mesa ethernet hardware

[vtsteam]

Happy Birthday Steve,

What’s it like to be 21, remind me 😀

I'll try to remember back to 1970, Andrew........lesseee.......uh, pretty good! 

[vtsteam]

howsitwork, I think those will probably hold up a lathe tool. 

RodW, thanks for the information, that makes it a lot clearer what the problems were, and what you needed it for.

btw I'm not buying my torch for CNC use, though I've built several CNC machines and do run LinuxCNC on a mill already. But really, this torch is just for occasional around the shop use.

[charadam]

I've had one of these for about 4 years.

https://www.ebay.co.uk/itm/CUT-50A-IGBT-INVERTER-AIR-PLASMA-CUTTER-HF-IGNITION-METAL-CUTTING-MACHINE-14mm/233573061881?epid=15042686762&hash=item36620a14f9:g:i84AAOSwHU5fGSor

It had poor consumables (especially the nozzles) but that was a cheap fix.

So far it has done about 12 hours (in 4 years) and has been a real boon.

I use it on a 16A circuit.

+1 for cheap Chinese.

[vtsteam]

Thanks Charadam, that's encouraging.

I've looked at a few videos for the brand plasma cutter I ordered (Amico). They seem to get good reviews and one person is a scrapyard owner, apparently and cuts up material with his machine commercially for recycling. He has one video of his cutter after two years of continuos commercial use. So that's also encouraging.

I decided to watch a few other videos for plasma cutters in general for DIY projects, so I typed in "DIY Plasma" I was very surprised to see near the top of the list a video of a CNC build using the exact same Amico torch I ordered. It's a quirky CNC build, and the kid who does it makes lots of mistakes and gradually improves his project. I kept wanting to say "Hey kid you have a plasma cutter AND a tig torch, let me introduce you to this stuff called angle iron. You can weld that instead of making thin gauge sheet metal parts." Or "Hey kid, you can get cable pulleys, or even sliding door track pulleys instead of filing roller skate wheels." etc. etc.

But in the end, I actually really enjoyed his struggles, and gradual self taught learning process, and he had a good sense of humor, laughing at himself. So you know what? I really did enjoy the video! Guilty pleasure at watching someone without much experience persevere, no matter what, and eventually get results.

Do I want to build his style CNC cutter. Nope. I don't see myself building one soon anyway. But did I learn something from his video? Yup. Even a few things to keep in mind when making things.

And it was really cool to see that, actually, my exact model and brand plasma cutter unit probably could be used for CNC. 

The video:

[Bee]

The ebay link above says HF start. Is that the EHT type mentioned? I've also seen 'pilot arc' mentioned as a must have.
One of the members of our Men's Shed said he had a 50A one and cut through the 1 inch window bars on a bank with it.
No, it was ok, he had bought a redundant bank building in our high street and converting it to flats. I'd have kept the bars as a 'feature'.
I assume you need clean metal to start the cut but will it then cut painted metal?
I occasionally get interested in one of these and would want to be able to cut a) cast iron brake discs to get small plates of CI and old computer cases or washing machine for sheet metal brackets.

[Sea.dog]

If you've a pilot arc you don't need to do any cleaning. Anything conductive can be cut with it. I've even seen someone cutting glass, albeit with a thin sheet of ali on top of it. the arc is at around 20,000°C after all.

[Pete.]

You wouldn't put your finger in the arc twice