How to Get a Good, Safe Welding Ground - How It Works and How to Work It
In response to a viewer who was concerned about getting shocked while welding, Kevin shows three different types of welding ground clamps and how they work. The first ground clamp came with a Longevity multiprocess welder, and the second from an AHP TIG welder.
On the Longevity clamp the ground strap hooks up to a terminal on a lug nut. It has nice, big copper contact pads on each side of the inside of the clamp. A copper sheet runs from one of those contact pads to the other to conduct the electricity. Kevin points out the burnt area on this particular clamp that indicates that its copper sheet has been overheated already or arced. Eventually, the copper sheet will burn all the way through and only one side of the clamp will conduct electricity and do its job.
On the AHP TIG welder clamp, the ground cable is again attached with a lug nut to a contact pad, with another pad on the other side. There's a heavy, woven copper cable between the pads that's better at carrying higher amounts of electrical current than the thin piece of copper in the other clamp. But the pads on this ground clamp are just "some sort of mystery metal," Kevin says. So they may heat up more quickly and not carry the electricity as well as copper contact pads.
The third clamp is a "big monster," all-metal version. It has a nice, big, heavy spring that takes a lot of hand strength to open, giving you a strong connection to your work. It has teeth, too, that dig into the work a bit, improving the contact with your metal. Instead of having a lug nut, this welding clamp has a bolt that goes down inside a cylinder that has a contact pad inside. To attach it, you strip your metal bare, twist it or otherwise neaten it - Kevin likes to solder the wires together to create a single chunk instead of loose copper. Then you slide it through the wire clamp and inside the ground and tighten the bolt. Finally, you squeeze shut the wire clamp with pliers so that any pulling on the wire is handled by that wire clamp and the handle body instead of pulling loose your ground connection.
How do you hook up a welding clamp so you don't have to worry about being shocked? First Kevin shows how, with his metal workbench, he has ground a clean spot on his bench and can just clamp the ground to the table itself and tuck it out of the way. The only problem with this approach is that your metal table is now "hot." You can now just set the piece of metal you want to weld on the bench, but if you lean on the table, especially if you're TIG welding or welding small pieces, now you're setting yourself up for a shock.
Get around that by clamping directly to your work, which often also gives you a better ground. Kevin shows some bells he is working on that he can lay on their side so he can clamp on their bottom opening. Or you can grind some areas on the work - so your ground can touch bare metal to bare metal - and attach a large clamp. Now you can attach your welding clamp to the clamp on the work so your work is now grounded, not your table.
What if your piece is too small? Just clamp your work to the bench. That will keep it from moving and allow you to ground to the bench. To address the shocking problem, Kevin recommends welding sleeves, which keep your bare arm off the table while also protecting you from the welder's ultraviolet radation and provide heat protection, too. Or throw a glove on the table to lean against to keep yourself off the table. Kevin points out that you should be wearing welding sleeves, long sleeves, leathers or other safety protection if you are welding, anyway.
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