Thread: Kemppi Minarc Evo

Bit late replying to this, but thanks for posting your findings. It sounds like the Miniarc is typically exhibiting less "arc force" than the Smootharc. To put it in more technical terms, it seems the Smootharc has relatively high (and fixed) arc force behaviour, in that it lets the actual amps rise considerably above the dial setting. Probably a good thing for thicker sections where you want the extra heat. Probably not such a good thing for thin sections. As I've mentioned, my UniMIG combo has much tighter control of amps - you set 100A and it won't let the actual amps go any higher than that, so that'd be low arc force. I'll have to try the UniMIG on some thin section to see if this makes it easier than with the Smootharc.

That said, from the specs, the Miniarc is a bit more sophisticated in that it can automatically vary the arc force, although I'd like to know what algorithm it uses to decide when to let the amps go higher.

The Lincoln that Grahame was talking about also has auto adaptive arc force. I wonder how its algorithm compares.

Today I did more test welding. With 1.6mm Gemini 12 rods, I went as low as 25A, just running a bead along a face of some SHS in the flat position. The beginning of each run was too cold, but once it warmed up enough (after about 15-25mm on various runs) it actually ran quite well. Slow travel speed and the funny thing was, the SHS was galv (maybe Duragal?) and once or twice it went pop! and burned a hole through. I could see it quite clearly. But after knocking off the slag, the hole was gone. It didn't do the usual thing when it blows a hole with normal amperage, when you get the hollow sound and there's nothing you can do but stop or quickly move somewhere else. Just a loud pop! and a visible hole that disappeared afterwards.

Surprisingly, at 28A the 1.6mm rods ran very well, with a neat controllable bead. Slow travel speed, no holes, not too cold, good penetration.

But I only ran a couple of 1.6mm rods.

Then I went with 2.0mm Gemini 12s (I rediscovered them the other day after quite some time on RB-26s - the Geminis burn very nicely I reckon and about the same price as RB-26). I went as low as 30A, not too bad, but just in the flat position. 35A was definitely manageable with good penetration and a nice slow speed and no holes. Then I did some butts and fillets and positional stuff. I'm still deciding, but at the moment I'm around 38-40A for butts, 48-50A for fillets. +10A for tacks for each weld type. I might go a little higher tomorrow and increase travel speed a bit and see what happens.

Still learning and experimenting, a few mistakes, but generally pretty good. The positional stuff was nice - I could do horizontal butts and fillets, overhead butts and along a SHS face, overhead 45 degrees fillets, vertical down, all with the same amperage I'd use for the flat stuff. The only one that was beyond me was vertical up, and I tried a couple of times, dropping down to 32A. The SHS is 2.0mm I think so I'm not surprised that vertical up was impossible.

The Geminis are nice for this positional stuff. I spent a lot of time with RB-26 and it has a very fluid slag in comparison. Anything besides flat is a challenge with those. The weld ends up looking alright afterwards but the slag just flows and flows in big blobs and it's a bit disconcerting.

Anyway, very impressed with this welder. I pushed it a bit, not cleaning off the galv (and then after doing the same with some rusty painted stuff). So contact was bad but it still held a steady clean arc all the time. It just feels smoooooth. Much smoother than the Smootharc, funnily enough.

I'm loving the Kemppi. There are two downsides:

- if you don't use it for a while, the fan shuts off to save a couple of watts. At the moment I'm working in the driveway and only have the one extension cord. When the welder is silent I've twice come very close to pulling the plug to use the grinder while the welder is still on. The one time I did that with the Smootharc pretty much every RCD in the house tripped.
- I've taken to using a file to break off the old flux to restart rods. I position it near the job and pick it up as required. Twice I've struck the file in place with one hand while it's lying on the job, out of laziness, with the hood up, and copped an eyeful of arc. The Smootharc was easier to restart and I didn't need to break off the old flux as forcefully. I used a pics of scrap positioned near the weld as a strike plate and that was enough.

But apart from those two issues it's great. The digital display is great for repeatability.

And I found a new source for Gemini 12s for $7.77/2kg in the 2.6mm size. They are nicer than the Kobes for sure, although the Kobe's produce a nice weld, unfortunately not as versatile in positional work. 65A in 1G, 78A in 3G (vertical down), 88A in 3F (vertical down), 3mm and 2.5mm SHS and RHS, went through most of a 2kg box today.
I can't bring myself to open the new box of Kobe's sitting there, nor to finish off the 10 or so rods in the last box.

I sold the Smootharc for $100 on Gumtree.

I tripped over the cord today, pulling it out of the extension cord and it didn't trip the RCDs in the house, none of them.

And yesterday I had a moment when I'd been measuring and fitting and the fan had turned off so everything was silent and then I was walking around the work and almost moved the electrode holder against the work, not thinking it was on. So the fan thing kind of sucks, for what would just be a few Watts. I'd prefer to know when the machine is on.

But very happy with it still. Using a file to knock off the slag makes it start instantly every time, much better than my old technique of a scrap strike plate.

Originally Posted by Legion

And I found a new source for Gemini 12s for $7.77/2kg in the 2.6mm size. They are nicer than the Kobes for sure, although the Kobe's produce a nice weld, unfortunately not as versatile in positional work. 65A in 1G, 78A in 3G (vertical down), 88A in 3F (vertical down), 3mm and 2.5mm SHS and RHS, went through most of a 2kg box today.
I can't bring myself to open the new box of Kobe's sitting there, nor to finish off the 10 or so rods in the last box.

Just save the Kobe's for somewhere you want some nice flat welds - they're a great rod in the right situation and I always have a box around, but I don't use many of them.
That's a great price for the the Gemini's - where's that?

Gemini's are from SBA Supplies in WA. Just to confirm they didn't make a typo, I bought their last three boxes yesterday @ $7.773 per 2kg pack after almost finishing off the other 4kg worth over the weekend. Not sure how the 0.3c is calculated at the checkout. I said I'd get some more if they have them when I go back to pick up a paint order.