Choosing between these 2 welders for car repairs (thin sheet metal)

[kilou]

Thanks @eddie49 for the feedback and links! That's highly appreciated! I will look into more details this question of amps readings as it is still daunting for me.

I contacted Ipotools regarding the strange max and effective current values. They told me that a 16A socket is sufficient for the MIG 160er and that they will check the current values on the sticker...
Overall, I think I will go with the Weldinger ME 160 eco. I just feel more and more uncomfortable with this Ipotools MIG 160 er. As already mentionned, the device lacks a removable torch, has no 5kg spool support and has a cheap plastic wire feed mechanism. But it seems that the information on this device is unclear/unreliable. I have never seen a single image of the MIG 160er with the technical sticker on it and when Ipotools sends me a pic of such sticker, the information it contains is incoherent with what is reported on their website. The fair amount of negative reviews on amazon regarding this device also points to a product of questionnable quality. The 7 years warranty appears appealing at first but you need to pay for return shipping costs (same for Weldinger). From Switzerland to Germany, that would mean paying about 25% of the price of the device for shipping, for each warranty claim! So not very appealing. I could find a Swiss dealer of the Weldinger ME 160 eco at a slightly higher price. He only offers two years of warranty but at least, if anything happens during these 2 years, I only need to ship the device to them in Switzerland, which is cheaper than having to ship it back myself to Germany. So in the end, I think I will go that route and get this ME 160 eco "locally" as it will allow me to better understand how MIG parameters are working together and the product subjectively seems of higher quality.

Thanks for all the very helpful comments! Great forum!

 

[kilou]

Just one last question: so far we' ve mostly been concerned about the min amps a machine can output for welding sheet metal. But what about min voltage? For example, the ME 160 eco has a min voltage setting of 15.5V. Although the device can go as low as 30 A according to specs, would 15.5V not be too high for sheet metal of e.g. 0.7mm thick, especially if a 0.6mm wire diameter is being used?

 

[kilou]

To be a bit more specific, this is what I found from this website:

"A 0.024-inch wire would operate at 13 to 15 volts (electrode positive) with a wire feed speed of 130 to 160 ipm, whereas the 0.30-inch solid wire would require 15 to 17 volts and 75 to 100 ipm wire feed speed".

So does it mean that a mig welder with min voltage of 15.5V cannot run a 0.6mm wire and should stick to 0.8mm wire? The other point which is weird is that the voltage range printed on the technical sticker does not match the voltage that the machine can be set at. An example is the Parkside PMSG 200 A2 unit which is rated between 50A @16.5V and 160A @22V. The amps cannot be set lower than 50A on the machine but the voltage can go all the way down to 10V on the display... So is the min voltage although of concern for welding sheet metal?

 

[eddie49]

The choice between 0.6 and 0.8mm MIG wire is usually a personal preference, with a slight majority of Forum members opting for 0.8. It is true that 0.6 wire has higher resistance and will carry less current, so using it is a way of slightly reducing the effective current range on a machine that does not go low enough. At the other end of the scale, above 180 Amps it is recommended to use 1.0mm.
As for voltage, it is easy to understand traditional transformer-based machines, with outputs that use full-wave bridge rectifiers and possibly tens of thousands of microFarads-worth of smoothing capacitors, resulting in almost pure DC. Older Migatronic welders seem to start their output voltage at the lowest values - just 14 volts is enough to flow 30 Amps. That means they use a low resistance output circuit, with copper rather than aluminium transformer windings, multiple large diodes in parallel, and thick copper busbars and cables and work return lead & clamp.
The voltage needed to flow enough current to melt the wire and the workpiece depends on the total resistance of the welding circuit. This does include the resistance of the arc itself - whatever that is...

Generally, voltage has only mattered to me when checking that a transformer-based welder is not faulty. Measuring "about 15 to 30 volts DC from the torch tip to the work clamp when switching through the 6 power settings" is a phrase I often use during troubleshooting.
It is not so simple with inverter-based machines. The OCV is often 50 or 60 volts, and the oscilloscope picture in post #9 here:

MIG welder torch voltage - general question

I've been using my Uptime160 MIG for a while now and it's working fine (slightly erratic welds recently but solved with a new tip). After reading threads about voltage, amps and wire speed I decided to test the welder to see what the controls actually control and what the voltage is at the tip...

www.mig-welding.co.uk

shows how complex the PWM output waveform can be. It is anybody's guess what an analogue or digital voltmeter would make of that signal. You would need a stable resistor ( "welder load bank" ) to get an accurate result on-load. It is not surprising that the controls, digital displays, and data plates of hobby-level inverter MIGs get confused!
As mentioned in post #2 of this thread:

Confusion of the dials?

Can any one explain the settings on my new Static Arc 140 Mig welder, the Volts dial has numbers from 1 to 10 and are straight forward as there is a digital display telling you what the Volts are but the wire speed dial also has numbers going from 1 to 10 and virtually all the Mig welders I have...

www.mig-welding.co.uk

professional welders using high-end machines and following written procedures will know the exact voltage, wire speed, wire size and gas mixture for a given metal thickness, but at the hobby level you just twiddle the dials and pull the trigger....