Mig or ARC Welder... What should i go for?

[wiatroda]

Yes, I agree, it is slower and you need pure argon ( for MIG you can use cheaper CO2). Some sources claim a thermal distortion is lower in case of TIG welding so I assume the heat you put into material is lower as well. The thickest part I TIG welded was 8mm steel plate with 16 mm bar, but it was at the very beginning of my TIG welding adventure with little experience in welding (see pic below) and I'm by no mean I was professional welder.

Of course it is possible to weld with sticks If there is an option in TIG inverter. In summary TIG initial an running cost is higher, but there is no spatters, post weld clean-up and is more precise. You just need to decide what needs do you have and choose suitable welding technique.

[m_c]

Yes, I agree, it is slower and you need pure argon ( for MIG you can use cheaper CO2).

Pure argon is expensive. I'm sure last time I checked, it was almost twice the price of Argoshield at BOC.
Although you can use CO2, it's far better to use the proper mix, as it does lead to better welds. The proper mix is Argon with a percentage of CO2 (the higher the percentage, the hotter/deeper the weld will be) and a trace of oxygen to help burn of any impurities.

Also, some CO2 isn't pure CO2. Some suppliers add nitrogen to make it useless for welding.

Some sources claim a thermal distortion is lower in case of TIG welding so I assume the heat you put into material is lower as well. The thickest part I TIG welded was 8mm steel plate with 16 mm bar, but it was at the very beginning of my TIG welding adventure with little experience in welding (see pic below) and I'm by no mean I was professional welder.

It all depends where you're measuring the distortion. As you can see in that photo by the blueing, the amount of heat has been high and has travelled pretty far. The plus side is the weld will be relatively free from thermal stresses, but you end up with a far bigger heat affected zone. With MIG (set so it's short circuit transfer) or ARC, the HAZ wouldn't be anywhere near as big, but the thermal stresses within the weld will be higher. It all depends on what you need from the weld.

I'm not a professional welder either, but I do have my MIG/MAG certificate (mainly so the employer can cover their ass should I put anything up flames!), and have had plenty experience bodging bits together using various combinations of welders to of learnt some of the things that are possible.

You just need to decide what needs do you have and choose suitable welding technique.