Thread: Kemppi Minarc Evo

While I can't tell you much about any bells and whistles on the Kemppi ,I suspect apart from the Digital readout amd extra amps ,there's not much difference as an electrode welder overall performance difference. Maybe so if you are considering the Tig process, but then add the extra expense of renting a cylinder and argon refills let alone the tig hand unit and gauges and torch consumables.

There's not a lot of practical advantage in a digital display. With any machine digital or not, the relative new comer (to welding) is still left with the task of running a test test bead and "reading" it as too hot or too cold.After some arc time you will tend to be not so amps orientated and rather set the dial by what you know you require, not by what the side of the electrode packet tells you.

Kemppis can go wrong. A mud dauber wasp laid a nest across a circuit board on mine Kemppi mig.The repair was to be a 1/3 of its $1800 purchase price. Check repair prices if you must have one'

Apart from the the digital display what do you have? An extra 20 amps or with the 180 50 amps with the bigger model. With the 180 amp jobbie you certainly will need an 15 amp plug, probably so with the 150 amp.You can use larger diameter rods ,but I find most guys I encounter use mainly 2.5mm rods.

This more expensive DC machine, in the end, will only do the same work as the cheaper model you have used. I have used a 130 Smootharc and found it punched well above its weight class. High school kids could not damage it, so that says something. If your 130 does eventually bugger up, throw it in the bin and as they are not cost efficient to repair and then get get yourself a bigger one.

Just my 20c worth
Grahame

Thanks Grahame. I'm not sure if all inverters are the same but I'd be interested in knowing. E.g. the Lincoln Invertec is another one that is kind of interesting. The list of features includes some that I doubt the Smootharc has:

• Soft and Crisp mode : Selectable arc modes for different electrode types.
• Auto Adaptive Arc Force : For a stable arc with low spatter levels.
• Built in "hot Start" For excellent arc striking.

I don't know how these work in practice, not having used one, but it sounds cool. Another feature I saw on one of these higher end machines was an auto-cutout mode that detected a shorted electrode and auto-dropped the amps to prevent sticking rods. I imagine with a flexible enough circuit and controller the engineers could program all sorts of features into these machines.

The digital output is for a numpty like me, who e.g. tries to dial in 50A but with my clumsy fingers it might be 48A or it might be 52A. In practice that's not such a big deal I guess but I like that you can get exactly 50A with the Kemppi. I'd also be curious how accurate the reading is, given how inaccurate the Smootharc is, where 50A might actually be 35A (based on that thread that one of the regulars did with a clamp meter).

You can also get a remote control with the Kemppi, to adjust amps on the fly or just position it near the job. Seeing I do a lot of 25mm stuff I could see myself using that feature, but I'm not sure if it's something that's worth the extra ~$150. I do do a lot of walking around to the machine and back, typically varying butts and fillets about 10-15A on the same material.

Just daydreaming, like I said.

I've also wondered how the hot start and all those other features actually work. Fundamentally, a stick welder is a constant-current machine, meaning it adjusts the voltage to maintain a set current, and that's pretty much all a DC welder can do, so I assume it has algorithms as to how it varies the voltage depending on the feature that's enabled.

For "hot start" I assume it increases the volts to make it easier to strike an arc, and allows the amperage to go a bit higher than the setting for a small amount of time.

I think Arc Force is a bit like soft and crisp which, more or less, allows both the open-circuit voltage to go higher, and also allows the amps to go a varying amount higher than the amps setting.

Hi,
As it happens they bought an Lincoln Invertec 150S at work, in the last few weeks. I likes it.
I used the Lincoln today as a matter of fact.

It welds good on on 1.6mm gal channel.I ran 2.5mm weldskill sticks on about 50amps ,soft arc and electrode negative. On Gal stuff I always scuff the weld zone with a flap disc and blow the fan on me while I weld.

More welding to do tomorrow.
Want some photos ?

Grahame

Originally Posted by Grahame Collins

Want some photos ?

Yup. As they say, pics or it never happened!

On the subject of DC welder behaviour, a while back when I stuck a clamp meter on the respective leads of my Smootharc 130 and UniMIG 165 stick/MIG combo - both inverter machines - I noted that each machine had different behaviour with respect to maintaining amps - the Smootharc was happy to let the amps go a lot higher than the dial setting (topping out at 160 amps with the dial at the max 130 amps) while the UniMIG kept the amps pretty close to what as on the dial. From reading some Miller stuff on the net, that implies the Smootharc has higher "arc force" behavior than the UniMIG. Note that neither have an arc force control, just an amps dial.

Yeah, I'm interested in your thoughts Grahame. I could also live with the Invertec, although I'd have to put in a 15A plug.

I was looking at the mini Kemppi because of the plug issue.

Invertec is cheaper too.

Tell us how you like the features and if the soft/crisp makes a big difference.

I like to think the auto arc force/hot start/soft combo would be great on lower than usual amp settings on thinner stock.

Bear in mind that the Invertec has a VRD built in it . At times it can be a real pita to strike an electrode to the point that you knock the flux off the rod.
The machine runs off a 40 meter extension and there's no drop of current. I am on the second 5 kg packet of Weldskill 2.6mm dia rods burnt on the new Invertec.


This second packet shows moisture damage right out of the packet purchased on Monday .There is white spotting and spalling of the electrode flux off the rod core. I wouldn't purchase them again because of this.
I will take some photos today.

Grahame

I got some quotes, just out of interest.

The Esab Caddy Arc 151i A33, which looks like an awesome machine, won't give too much change out of $2k once you add tax.

The Kemppi Minarc Evo 140 and 150 are closer to $1k + tax, as is the Lincoln Invertec 170S

The Invertec 150S is a reasonable deal by comparison at ~$700 + gst.

As promised, here are the pictures but before that some background on what sort of welding I was doing .

I was welding on some 100 x 50 x 1.6mm C channel to 2mm 50 x 60 x 1.6mm angle iron. Also welded some 30x30 x1.6mm box -painted,no gal.It welds Ok.
The electrodes were Cigweld, Weldskill GP 6012 2.6mm diameter rods. The fabrication is for some welding screen feet. The boss wants to use up this old material we have on hand.

Pic.1.
First up is the machine control panel. There are only 3 controls to play with , obviously one is the amps dial, the second ,the dinse polarity plugs and lastly in the left hand top corner is the mode button which cycles through the arc control program which simply put is low energy arc, high energy arc, and the tig setting read from top to bottom.

Pic 2
the info plate –a bit out of focus


Pic 3
The 2 year warranty sticker.

Pic 4
The pic is of the end of the channel that has been filled and stiffened using the 50 x60 x 2mm gal angle.Note is was scuffed using the side of a 1.6mm cutting disc.Its critical to get rid of as much of the coating as possible.Note the tack as is has a gas bubble.This is the boiling gal, gassing out, as the weld solidifies.The little black marks on the bead are from the edge of the half round round file.Only really noticeable on super macro.

I have more but they are taking ages to load.

Pic 1.
The angle is tacked on to the 100 wide section of the flat.Tacks are plenty strong enough.
Full welds only encourage a burn through.


Pic 2.
The box section is epoxy painted 30 x30 x 1.6mm box.The material tacks well if the painted surfaces are scuffed off first.
Pic 3.
Same deal with the gal for scuffing - get rid of the coating. The edge that can be seen is 2mm thick. The section on the left is is is 1.6 mm gal.

Pic 4.
The tacked box section was held in the vice at about 45 degrees and quickly welded semi vert down at very short arc length.


The welder will do the job of welding 1.6 wt but technique must be used.

Cheers
Grahame

So is it any easier to weld that thin section with the Lincoln compared to the Smootharc?

Originally Posted by RustyArc

So is it any easier to weld that thin section with the Lincoln compared to the Smootharc?

Yes,but only because I have heaps more Arc hours on it.

The arc control works well.Todays effort was on straight polarity. I never even thought about going to electrode positive. I only did a 1.6mm wt job,once, with the Smootharc
to show a kid it could be done.
Grahame

How come the gap on the 30mm x 30mm x 1.6mm SHS Grahame? Intentional or accidental? Does that not make it very difficult?

The gap looks bigger then it is due to the macro close ups,I think.
True there was a bit of a tapered gap due to the chop saw.

On the saw we have, the particular brand of blade is too tin and flexes laterally as it cuts its way through the section. I could have dressed it back to square ,but opted to weld it as is.

Below is a sharper view of it set up to weld and another bit blurry after welded. Two of the sides on this butt weld joint had a similar gap but nothing critical.

This ungalvanised stuff (painted black steel ) is much better to weld than gal coated though it is also prone to gas bubbles in the crater as you can see.I think it the epoxy paint reacting.
Its not exactly the same weld but its from the same joint and typical for all 4 sides.
I tried electrode positive today but had troubles initiating the arc at times. It could be the new damp electrodes or just the damm VRD.

If I go back on this same job, next week I will try some RB 26.s, some Satincraft and some Korean electrodes I have.

Grahame