Welding

I'm just getting into welding, and I'm going to try and learn mig.

Truthfully, I haven't even attempted it yet. I've just been gathering the necessary material and this weekend I thought I had everything I needed.

Unfortunately, me being the ignorant person I am, I got an inert gas tank from a 3rd party and swapped it at my local airgas for a 100% argon tank.

Most of you probably see the problem. I haven't used any of the gas yet, and I'm hoping to be able to swap it back for the blend and pay the difference. However, if I'm unable to I wanna try and come up with some alternative options.

Option 1: I work at a brewery and was hoping our gas supplier would be willing to swap it, but I'm not sure on that.

Option 2: I'm trying to see if a gas blender is feasible, as I already own a CO2 tank. And perhaps I could use the argon tank later for tig welding and get a CO2 tank that isn't beverage grade and be all dandy in that regard.

Option 3: Just buy another tank, I like this option the least as they aren't cheap and that means the argon tank just sits there and collects dust.

Option 4: Just learn how to tig welding first.

What would you do in this scenario?

I have very little experience and I'm looking to get a welder of my own.

What welder would you get and why? It can be any of the types, but try to back up why you'd pick that one.

This is part 4 of his series fabricating a belt grinder

Been doing stick welding for a bit, but when it comes to thin steel such as on cars, sticks blow right through. I was thinking about getting a flux core machine to do some exhaust work on my car because I don't want to mess with gas.

What should I know about flux core? What are the biggest cons about it?

-pulling my hair out-

Press for hub assembly did not work due to not having correct shim, so make one your self I said!

I'm going to learn some welding and I've bought myself an auto darkening helmet. I tested it my holding it up to the sun, and it darkens, but stops darkening right away (depending on the delay I set). Also tried with a powerful flashlight and it does the same. Also left it outside for a while for the solar panel to maybe charge the battery, no dice. Is my helmet is defective or is it going to work as intended with real welding?

I need to weld some nuts to a steel tube. Are there any issues with using regular zinc coated nuts or are there other, plain steel nuts I should be using?