Make sure the duty cycle is high on whatever you buy.
duty cycle is the number of minutes out of 10 that a welder can run continuously at full rated power without resting. 30% duty cycle on a 200amp welder means you can run at 200amps for 3 minutes straight and need to let it rest for 7 minutes. %50 of my job at work is welding, and my welder here is 60%. ive used the full power of the machine on some thicker stuff, and i cant tell you anything ive ever dumped 200 amps into for 3 minutes straight without killing it, and i still have another 3 minutes to go without over heating the machine. we're all hobbyists here, duty cycle doesnt matter to us(unless you buy a $100 chinese welder with a 30 second cycle...) in fact, welding car sheet metal, first youre not even close to being at full power so by definition its literally impossible to reach that timing, plus if you welded flat out you'd warp every panel you touched. even welding suspension or chassis parts with more amperage, you need to level, align, clamp, grind, bend, sip your beer, go take a piss, make fun of your friend standing there not helping, patting your dog, oh ya, then weld a three inch bead on a frame rail, then repeat... no one here needs to worry about duty cycle . Anyone who is buying a welder for a production shop where of the 8 hour work day youre making sparks for 7 hours straight, you're definitely not going to being asking a forum which 110v welder to buy. duty cycle for any hobbyist, even a hardcore welds a boatload kind of hobbyist, is simply more money and not an option thats worth it, just makes the machine waaaay heavier. the trend for almost everything, typically, is get the biggest you can afford, building a garage, buying a gun safe, or and air compressor, people think the same goes for welders, but if youre only welding sheetmetal, theres very few big *** machines (all of which cost about as much as an entire rusted out b body project) that can be turned down low enough for great welds on sheet metal, ya theyll work but theres a lot of post work to do, grinding off the extra bead, flattening out and body working the panel. buying an appropriately sized, small welder will give you all the penetration you need with very good control over the full range of voltage and amperage you need to use so you can fine tune it, you cant do that if the knob is turned all the way down.