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16th Nov 2012, 04:42 PM #1Novice
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Are Uni Mig Stick Inverter Welders any Good?
I Bought a UniMig Stick Inverter 170amp approx 4 months ago and I hate it. Would like to hear other peoples experiences with this machine.
I,m a newbie stick welder and i think most of the problem is me.
The biggest problems are.
1. sticking rods, tried varying amperages, techniques and welding rod types.
2. Difficulty maintaining a stable arc. It just dies and the rod sticks.
3. Burning holes in the metal and slag holes / slap entrapment.
My father has an old monarc 130amp stick welder, whilst i can't weld brilliantly with this machine.
I find it much easier to use.
So is all the fuss about inverters just hype or are they really better than old transformer machines.
Any advice would be greatly appreciated.
Thanks Pete.
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16th Nov 2012, 05:16 PM #2Member
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This is the first time I have heard anything bad about this machine
I know lots of welders who use them not only diy, It handles industrial use better than it should for a $300.00 machine
try using a different electrode
Magmaweld ESR 11 give a good weld
Also (I know its obvious but you'd be surprised how many do it )
Check the polarity ,
If you still have problems it might be a faulty unit so bring it back to the shop and have it tested
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16th Nov 2012, 06:44 PM #3Novice
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16th Nov 2012, 07:03 PM #4Member
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If you are not able to get a weld with those electrodes it might be worth getting the shop to have a look at it
or it could just be your settings generally with small inverter welders they either.. do nothing ,go bang ,or work well
Very rare to have them not quite work
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16th Nov 2012, 09:13 PM #5Diamond Member
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While all stick machines are essentially constant-current devices, with inverter units the way this is done varies, and does affect how they behave. For example, my UniMIG combo machine has strictly-regulated current, meaning if it's set to 100 amps on the dial, that's the max it will put out (actually about 95A when measured) , even with a stuck rod (dead short). Contrast this to my little BOC 130 Smootharc inverter - at 100A it'll do about that when running a bead, but if the rod sticks, the current will actually go up to 140 amps. At 125A on the dial it'll max out at almost 160A on a dead short.
If the setup and technique are good, both actually weld about the same.
Despite being the same brand, I'd expect that the UniMIG stick machine is probably quite different to my combo unit, as they seem to be Chinese-sourced units, each model based on a particular design which may have little in common with each other and are mass-produced and packaged/badged for different brands.
I have noticed my old man who used to have no problems welding with the BOC Smootharc now finds it easier to use his massive old AC unit, so there may be something about the different behaviour between AC and inverter DC units that makes it easier to use one than the other for different people.
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16th Nov 2012, 10:03 PM #6Intermediate Member
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What thickness material are you welding? What sorta amps are you running? What size rods are you using? Sounds like you need to up the amps a bit more, disregarding the burning holes bit.
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17th Nov 2012, 05:56 AM #7Novice
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Rhs thickness 1.6 to 4mm even the 4mm I blow holes in.
Various flats and angles between 3mm to 10mm
Rods 2mm approx 50 amps,2.5mm 80-90 amps, I can't get the murex rods to even run under 90 amps despite the packet has a maximum of 80 amps.
3.25mm 110 - 130 amps.
If I manage to get the machine to run reasonable today (rare) and come back tomorrow on the same project I,ll have to fiddle with the settings.
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17th Nov 2012, 06:26 AM #8Novice
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Rusty,
Those massive old ac units are the best.
I used battered and worn old massive ac units (3 phase) at Tafe and they ran like a dream compared to the junk I have at home.
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17th Nov 2012, 09:28 AM #9
Gidday Bigpete, I have got one of these machines and have not had a problem with it. I have had it for nearly 2 years and find it great to use. They are branded as unimig but its a Jasic brand machine which is a chinese made unit. Jasic is probally the first chinese brand of welding machines to hit our shores and possibly one of the far better made and reliable brands around. I have a couple of their machines ( JASIC ) and they have not missed a beat.
There maybe a problem with your unit and with it been a unimig you will find that they have a 3 year warranty and getting the welder looked at or even replaced is what i would do. The other thing is that machines are upgraded regularly with new components and there could be a parts issue on all the 170's that came of the line when yours was assembled.
Try the welder from different outlets, make sure its not tig mode and look carefully at the rod holder head to see if electrode is seated correctly and making good contact. The other important thing is place the earth clamp on a clean surface on the bench or on the work peice itself. Sometimes placing the clamp on the bench can cause bad earthing.If you are still not happy return to place of purchase and tell them nicely your problem. A smile will always mean a good and fast result.
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17th Nov 2012, 09:51 AM #10
Hi Big Pete,
I would agree with the rest of the blokes .
If you can weld ok with AC welder, it should be an absolute doddle to use your inverter.
That at least points towards problems with the machine or welding consumables , not your skills.
If there's consistent burn through problems it would indicate the machine real output does not match indicated output.
I would say its likely that some electronic component has failed or at least operates intermittently.
Probably being Chinese in origin I find they don't worry a real lot about quality control.
If its still in warranty, take it back for sure. If possible get some other experienced welders to run some electrodes on it. Take photos of the weld test pieces and maybe some opinions on paper from the "testers". Ask to test the unit before you accept it back after repairs.
My feeling would be the unit likely to be replaced outright as there are not a lot people around with inverter welder repair expertise.On lower cost machines like the 130 Cigweld inverters they are replaced as the repairs can often exceed the original cost of the unit.
It would not hurt to follow up on the outcome good or bad as bad word of mouth can make a real difference to sales.
I hope you can resolve you problem quickly with out too much hassle.
Cheers
Grahame
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18th Nov 2012, 09:45 AM #11
2012-11-18 09.17.57.jpg2012-11-18 09.17.28.jpg
This is my unimig 170 and i have been very happy with it. In regards to bigpete test the amp dial to make sure its not ''loose'' when turning as there should be a little bit of resistance. There is a small screw underneath the dial that may be loose, just another thing to try. Keep us updated.
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18th Nov 2012, 01:31 PM #12Novice
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Thanks for the advice and suggestions guys.
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18th Nov 2012, 05:35 PM #13Golden Member
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Three phase operates differently to single phase and is always easier to weld with. Single phase goes through a null point where the power switches off, then on again and while seemingly not noticeable to any great degree it does affect the welders performance. Three phase does not suffer from this and that is the reason they are or seem to be a smoother unit to use. Using any sort of extension cord will always make a single phase welder a difficult thing to use also due to current loss and so will wiring from the board that is not up to the job.
CHRIS
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18th Nov 2012, 06:27 PM #14Diamond Member
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I was going to mention that, as I remember the massive old 3-phase welders at the TAFE course I did running smoother than the nasty buzz of the old single phase AC unit we had in the workshop.
But then I thought about how those units actually worked and what the output waveform would look like, as it'd need a 3-phase to 1-phase transformer. Anyone know of a diagram for one of these transformers?
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23rd Nov 2012, 01:46 PM #15Most Valued Member
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Got to be a problem with either the unit or your power supply. I don't suppose the low power issues coincide with your wife cooking tea or the like, (assuming an electric stove or oven)? Are any of the leads/connections getting hot? Check both input and output leads thoroughly, excessive warmth is the first sign of a problem.
Inverters are about the most forgiving welders that you will find being a DC power source. I fact I find that far lower amperage than suggested can be run using DC.
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