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I think maybe my mentioning of "thin plate" was misleading in my original message I'm talking 3-10mm plate and bar. Basically, making racking frames, welding box section...that sort of thing.
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I lived my teen years on the farm and we used stick welder (MMA) to fix just about anything that had to fixed. Then I rented/boroved MIG to fix cars, my first car had a deer visit indoors.
Now I have invertter MMA and I say that for what kind of welding you are planning to do probably MMA would be most economical and educational choice. I had (and still have one) buzzbox cheap and nasty AC MMA. I don't recommend them unless you have a good teacher and are with really small budget. It's hard to use and very limitting. Bigger ex-industrial transformer welding machines can be had if you are willing to cart them out (least here some time ago) but tehy might need 3-phase supply, then again you 650A supply for hig % vs. 50A 50% of the nasty ones.
Compared to MIG/MAG
+ no gas
+ you can buy and use very different sticks, MIG/MAG you need to chance reel and possibly burner liner, nozzle etc.
+ Good versatility
+ inverter machines are pretty good, even the cheap ones
+ Some inverter MMA welders go down to 5A and offer remote control and TIG controls for added flexibility
- if you need production efficiency MIG is better, but megabucks with the cylcle you would need.
- thin plate is much harder and modern car body work not really feasible.
For car body work and other thin plates that needs some capacity MIG/MAG would be my first choice, but really hard to get any half decent machine under 600€ and almost decent is a bit over 1000€ + gas bottle + gas + old reels of wire you throw out + consumables.
Compare that for MMA, where you can buy half decent inverter 200€ range and very nice at 500€. And specially when there is very little extra expences and consumables to spend. Maybe longer and better cables that comes with cheapest ones (really cheap ones have something that looks like jumper cables and toys-r-us type stick holder and earth clamps).
I bought one ex-industrial inverter that i could use for TIG for about 200€ single phase from 10-160A (althought it needs over rated mains outlet at 20A) and only once thermal switch tripped when I was welding non-stop storage racks outside on good sun.
And one thing: Buy good helmet, gloves and cover yourself fully. Don't skimp on this one.
Happy huntting,
Pekka