|Label says it's made in China|
I found the above copper wool in a store and snapped up a pack. When I reached home the first thing I did was to grab a big magnet and check whether this is pure copper or just plated. What do you think? Well, it clung to the magnet but not as strongly as ordinary steel so I suspect the base metal is some type of stainless steel.
Well copper or not, metal wool makes an excellent "sponge" to create lots of small good contact points between the ground clamp and the workpiece to be welded or the welding table. I now use the copper plated wool whenever I weld. It gives me greater confidence while welding in that it completely eliminates one variable--bad ground connection--when the weld isn't going well.
Couple of months ago I hacked my MIG ground clamp by cutting and stripping several feet of AWG#14 solid copper wire, folding it at the middle and then looping that around the screw that secures the lug of ground cable and then finally winding the rest of the wire around one of the jaws of the clamp. The idea is to have the copper get clamped onto the workpiece. The wool now further increases the area of contact thus further decreasing electrical resistance.
|How I use the copper wool. It gets squished between the copper-wire-wound clamp and the workpiece. In this example I've folded the wool around the flat iron so that the bottom jaw of the clamp also presses it into the bar.|
This wool is rather course and I would think that a finer one would be even more effective. And given a finer grade's greater pliability, it can be folded and pressed/crushed far easier than this one I'm using.
Hat tip goes to Jody Collier of weldingtipsandtricks.com. In one of his vids he talks about using flexible heavy gauge welding cable and stripping the insulation off and using that with the ground clamp to increase the surface area in the interface between clamp and work piece. Jody has some of the best if not the best welding vids on Youtube. His tips are beyond valuable. Go watch and subscribe.