Minimum 40A welder suitable for bodywork?

[Soundstorm]

Hi, thanks for all your help!

I found another welder. That one is 30-170A, so maybe better for me. It's also newer, cleaner and doesn't have rust. But maybe I will buy a circuit like that to get even lower than 30A. Not sure yet.

Do you have a schematic on how to connect it?

 

[shenion]

30A is fine.

I have lowered my Clarke by using a variac. Was a 20A variac on the input side (2.4KW). Was able to lower it. I was trying to do thinner aluminum, but found later I actually needed more power and move fast rather than low and slow.

You can find variacs on ebay. Often used in theater lighting and are recovered from old buildings.

My Miller goes down to about 17A. I found it easier to weld at 30A and move faster. At such a low current the wire feed is real slow and the arc/wire has time to wander.

 

[Soundstorm]

That's great then.

I thought that with lower amps, it would have been a bit more easy to learn. But I guess thicker metal will be better.

 

[malcolm]

I bought a variac with the plan of trying that. Haven't got around to it yet as it still needs a nice safe box building to house it.

I've always felt there was more to come from MIG welders at lower voltages than they will drop down to - I'm always on the lowest setting when anywhere near a Renault. Though I've also been told the arc will be rubbish.

Soundstorm - don't try learning on low amps. MIGs are easiest to work with and learn on when they are set for about 2mm steel.

 

[shenion]

To be fair, I was using 0.6mm wire on my supposedly Tweco #1 gun (ebay deal.) On closer inspection the gun had a 1.2mm liner and was a MiniMig gun (no part # on gun.). It is 12' so you end up with the wire being a very long coiled spring. Caused lots of stuttering when wire speed was so slow (was down to probably 60 ipm.).

I found it odd that a 180A gun had a 1-1.2mm liner. I replaced it with a 0.8mm liner; definite difference but I had finished the project.

The other issue was the heat. As I was moving sooo slow, the weld pool got wider due to more needed weave. That caused more distortion and as I was doing an inside corner, as it sagged, it would pull the arc off one side, run up one side and blow through. Moving faster eliminated the arc wander.

As the bead was narrow, you had to do a more weave to get fusion as it would pull the arc to one side due to the sharp edges of the metal.

My best welds were doing vertical down as I could move faster with less weave, still 100% penetration after a bit of adjustment (close to 30A). Was easy to turn cart on side, hard to do on an auto

Give the variac a try, I can't say it helped or hurted. I put it inline with the power cord, best would be on the main transformer primary as it would then not effect the wire feed (assuming MIG as separate power for feed.) Was doing Alum, so the 30A on the Clarke was probably near 40A. Again, ended up increasing power and moving faster as cold starts got worse.

It would probably work to drop to about 25A. Below that (I was at about 18A), it is just too slow. On the Clarke, the arc was fine although more sensitive to torch shaking.

I bet the reason <30A is not popular is it requires better torch skills as it is soo slow. It also requires more windings in the primary, another cost issue.

BTW, this Miller is basically one huge, 250lb, 14-40V variac Has a big crank on the front that turns 3 threaded rods to move sliders. Probably 100 turns end-end.

 

[redhand010]

I have a powershack 190 welder and that starts at 40amps so would I be able to use a variac on mine and how would I fit it. I know nothing about electronics??