Battery, jump leads = Welder

[uks]

http://www.bing.com/videos/search?q=WELD...FORM=VIRE8

We've done this on an expedition works OK. Works with 12 v batteries as well.

[Highlander]

Interesting, I will remember this one,..thanks

[Straight Shooter]

great post uks I to will lock that into my brain forever .....loads of rods in my garage...

[Dorset Lad]

I certainly wouldn't want to be doing this infront of the batteries as the guy in the vid was doing. If the rod was to "stick" to the work as happens in stick welding, you have effectively short circuited the battery. Lead acid batteries have a nasty habbit of exploding when you short circuit them or at the very least getting extreamly hot. You could melt the insulation off of the leads too.
In my oppinion this is something for dire emergencies only.

[Mortblanc]

It is for use in emergencies only and it does not give a deep weld. You might get a thin section tacked together for a trip out of the woods but it is not going to be a permanent fix for a major component in any way.