MIG Welder amperage for body repairs - 120a or 160a

[AUS911SC3]

I've been offered 2 quality mig welders at a seriously low price however 1 is a 120 amp and the other is a 160 amp. What amperage is recommended for body repairs on early galv. Bodies. I'm tempted to go the 160a but concerned that it's too powerful for the metal type. Any advice is appreciated.

[abisel]

Get the 160 as long as the heat settings can be turned down enough to work with 20 or 22 gauge sheetmetal. I have a Millermatic 150 that runs on 220Vac and I use the lowest setting (1) and the next setting (2) for my body work. Even at the lowest setting per the guide attached to the machine, it will still sometimes burn through. So I have adopted a spot technique with overlapping spots.

Get the 160 as there will be times when you will want to weld thicker material.

[whiskyb]

Pay attention to the duty cycle as well. I vote for the 160 as well if it can be adjusted down

[dicklague]

Get the 160. You will be able to sue it on other jobs as well. the all have a dial to adjust the output.

On sheet metal you use a spot welding technique any way. You are not going to lay down a bead, because that would heat the metal too much and not only burn through, but warp it as well.

[john walker's workshop]

25 to 30A is all you need for 20 ga. If either one has smooth rotating dials instead of click type, i would go for that one. easier to fine tune. 220 works way better than a 110.

[Tippy]

Get the best brand. That matters the most.

[sundevil64]

A 120a will work fine for sheet metal,but I would go the 160a should you want to eventually weld something thicker. I have a 160 and it works great. I sold my 145. It was borderline for 1/4". Make sure it has infinite adjustment for both feed and amperage. I would stick with a name brand such as miller, Lincoln, or ESAB. I have an old school Century that was later bought by Lincoln. It's a good welder for my needs. I only run a 30amp breaker and I have never thrown it and I have welded 1/4".

[jmpowers]

The 120 will be 110v and the 160 will be 220v. What power do you have available?

[FrankBlack]

I wouldn't worry about the amperage so much. You really need to test both welders on material similar to what your welding.
Most welders do a great job on anything above 1/8th thick.
But not all machines are equal when it comes to welding thinner material.
I've tested cheap Chinese machines that have been amazing. But also tested more rubbish than I can remember.

Just my 2cents gathered from 25+ years in the Motorsport fabrication industry.

[john walker's workshop]

Frank, what's your favorite 20ga sheet metal machine?

[WANNA930]

Better off having too much then too little power even for sheet metal.

If you see a lot of pic posts in regards to sheet metal welding they never use enough heat/power. Having a million spot welds that sit on top of the metal do nothing especially when ground down. That is why welds crack. Its not the supposed bad bondo but the weld underneath it failing. You should be right on the edge of blowing through.

180 is probably best all around machine. There is no real great machine for MIG welding sheet metal as you wind up with a hard weld and warped metal. Without penetration as noted above people chase a flat panel with a grinder destroying the weld and surrounding metal.

You can't work a mig weld you can only get it close. That said you can get it fairly close if needed. It is the finish work that is impossible to get get dead straight.

Set up your machine before every use. Make sure everything is surgically clean including nozzle and tip.

Do not grind or sand with 36 grit disc before welding it thins metal. Biggest mistake you always see.

Have a gap at least the size of the gauge of metal welding.

Do short welds at a time and try not to spot the whole panel in in creates pin holes.

work metal as you are welding while it is cooling for next weld

grind the weld not the metal when finishing.

[FrankBlack]

Frank, what's your favorite 20ga sheet metal machine?

We only use miller machines. They're the industry standard. Super reliable and can always get spare parts.

Another pointer when welding sheetmetal. Y
ou should always be able to place your bare palm on the metal no further than 1" from your weld. I usually place my tacks 4" apart and take my time. Always being mindful of not getting the metal too hot.
Heat's your friend and enemy.

[john walker's workshop]

just wondering. done it for years and also been through several welders i didn't really like for sheet metal work. miller 180 mig and tig at the moment.