Picked up a used AC-DC stick welder

[JimR]

I picked this Craftsman AC/DC welder up today for $65.00 with the cables and a cheapo helmet. My Tombstone Lincoln is only AC (edited) and can't weld aluminum. This will do the trick if my Mig can't handle the job.

 

[Spiffy1]

Another good buy!

BTW my old tombstone is AC only and I was thinking DC for aluminum (never tried it though).

Typo, or different unit?

 

[JimR]

Your right. AC it is. It's late and it has been a long day for me. You cannot weld aluminum with the AC unit. I tried, all it does is blow the rod away.

 

[Doc]

Man, another great deal!

I'm just in the thinking stages (again) of getting a welder. I don't know much about them so I'm afraid of getting ripped off on a used one.

So I know basically what AC and DC is, but when using a welder on DC where does the welder get it's power? Is it just converting AC current to DC internally or what?
I thought AC / DC welders were way more expensive than AC only ones. 65 bucks sounds like an awesome deal.

 

[JimR]

An AC/DC welder is almost twice the price of a AC unit. I think the Lincoln Tombstone AC is $299.00 and the AC/DC is $499.00. I don't know a lot about what makes then tick either. They do somehow change the current inside from AC to DC. The DC welding amps is only 140 on this unit. I think I read somewhere that you can do this using diodes. I'll have to read up on welding with reverse polarity and such. I know when I bought some aluminum rod recently, the salesperson said I needed a DC unit to weld aluminum. Last night I was doing some research and found that you can reverse the polarity on an AC unit to weld aluminum. That is pretty hard to do if your cables are routed to the insides. This unit has the plug ins on the outside and the cables do interchange between all the plugs. $65.00 was a steal for even a well used unit like this. It did cost me $15.00 in gas to go get it. The welder is getting wheels put on it today. It is too heavy to be hauled around except with a two wheeler. I had all I could do to lift it out of the trunk of the wife's car.

 

[Spiffy1]

I'm pretty sure all the older ones use a diode system for the "rectifier", newer ones may be solid-state, but I'm not sure. The way I see it, unless you stumble across a steal on the diodes, it's just as easy looking for a good buy on the AC/DC welder. Of course, I've yet to find either (not looking too hard right now though).

There might be some that are reverse or straight only, but unless they are the "plug type" I've always seen a polarity switch; or even AC, DC, DC reverse.