Welding with 2 batteries?

I snapped a rear axle shaft off inside the carrier, so I'm trying to weld a couple of welding rods together and tack them to the piece of the axle shaft to yank it out. It broke up in the hills behind my house, so I'm trying to do it with 2 car batteries and some jumper cables.

I didn't know how to wire the 2 batteries in series, but i thought it was a pretty simple concept, so I took a stab at it. I ran a cable from the positive on one battery to the negative on the other battery. I then used the negative on the first battery as the ground, and the positive on the other battery as the welding lead.

When i started welding, it arched at the positive terminal of the first battery. Did I set it up wrong? I don't want to kill the batteries.

 

Hmm.... sounds right... but I'm no expert.

 

you would get a much better connection and eliminate the arcing at the battery terminals if you cut the clamps off the end of your jumper cables and use some good old clamp on battery cable ends. $.02

 

Isn't that picture backwards? Shouldn't one be using the positive lead for the welding rod, and the negative lead for the ground?

Or does it not matter?

 

Hmm - learn something new everyday. Glad I saw this b/c if the situation would have ever came up, I would have hooked it up backwards.

 

I was trying it backwards from what the pic shows... AC welding maybe? I'm assuming I should switch it so I'm using DC?

 

That looks like something I need to try!!!

 

Is it important to hold it only with the insulated part of the clamp? What kind of electric shock danger are we talking about here?

 

Id imagine it wouldnt shock too bad, but I just wear welding gloves and then I don't even have to think about it.

I tried again, and learned a few things. The first is that the splines on the shaft are probably twisted pretty good, so I'm going to have to pull the carrier to get it out. Second, do not try this using reversed polarity with a battery still hooked up to the vehicle you're welding on. The electricity travelled through my new stainless steel brake line, destroying it and draining my brake system. And it probably melted a few other things I haven't seen yet.

I got a rod stuck pretty good to the broken axle shaft, but it still wouldn't pull it out. So I think I'm going to put the rest of the broken shaft back in it and drive it home without brakes so I can work on it in my driveway. I still haven't found a replacement axleshaft either, so at least it won't be sitting in a creek in the middle of nowhere while I track one down.

 

We could have really used that picture of the batteries about 2 weeks ago. We were on the Ducy trail in the Central Sierras and one of the rigs spring perches let go on the rear axle, sending the pinion pointing straight up. We had the rod and someone who could weld but damned if we could figure out how to hook up the batteries. We ran into someone with a Ready Welder and got things fixed about 4 hours later.

 

It's not intuitive, but electrons actually flow from negative to positive. So in DC welding you want the electrons to carry the melted welding rod to the work, not the other way around. If you are AC welding then it doesn't really matter which electrode goes where.

 

Oh, you are definately welding dc no matter how you hook it up. Batteries are not ac power. You would either be welding dc straight or dc reverse polarity depending on how you are hooked up.