Can a welder be to big?

[brewchief]

I am going to look at a tig welder in the next day or two the price is right but it is old and big, 400 amp big:D is there a downside to a welder this big used in a hobby type shop? It's dc only so it won't do aluminum but the welding shop says I can add a HF starter box that will also add ac for about 900$ the guy only wants about 300$ for the welder so I'm thinkin it's a good deal
Brewchief

[FullsizeYota]

I am going to look at a tig welder in the next day or two the price is right but it is old and big, 400 amp big:D is there a downside to a welder this big used in a hobby type shop? It's dc only so it won't do aluminum but the welding shop says I can add a HF starter box that will also add ac for about 900$ the guy only wants about 300$ for the welder so I'm thinkin it's a good deal
Brewchief


there shouldn't be any ill effects. the only real advantage to that machine are the 400 amps:grinpimp: but where you'll probably never use 1/2 that, the only advantage you see will be an improved duty cycle...

oh ya and thats gonna be a big fawker:grinpimp:

[Pin Head]

The good news is that your friends won't ask to borrow it.

The down side is that it is going to need a 125A 240V (assuming it is single phase) circuit to run it full bore. Chances are that the largest breaker that you can get in your box is only 60-70 amps so it will only run about half power (which is still a lot).

If it is missing the HF, the foot pedal, the Tig torch and argon tank, then it is basically just a buzz box stick welder. There may be $300 worth of copper in it with the current scrap prices.

You may run into trouble with the breaker tripping when you turn it on. There is a huge current surge when you energize the transformer that may trip the breaker. I run a 250A Tig welder off a 50 A circuit and about 1 in 10 times I flip the switch it will trip the breaker. Otherwise, it runs fine up to about 75% power.

[Wicked_S10]

Adding a HF arc starter/stabilizer does not add AC abilities, it merely starts and stabilizes the arc for AC tig. The machine has to be capable of ac arc welding to begin with. A HF starter will allow you to start DC welds w/o scratch starting, which is nice, but not the same thing. Anyhow, I have a single phase dialarc 250 HF, I believe the max setting is 300 amps, and the maximum current draw is 105 amps at 240 vac. I highly doubt that a 400 amp machine is single phase. If it is a goldstar or the like, they are DC machines like you describe, but were 3 phase only IMS.

The biggest downfall of a machine that big, will be limited low current capability, which you will want for tig. My dialarc can only go down to 25 amps, 5 amps would be nice for some of my sheet metal tig work.