When you have a no arc strike in the clamp . If the have an arc you know that's it the clamp to work issue.
The wires connected to the clamp will break over time underneath the rubber, seen it at school. If that's the case, Just trim up the wire, reconnect clamp and should be good.
You have a long way to go to catch up with the rusty **** I've welded over the years, but keep trying, you might get there. I quit messing with sand paper and went to a grinder to clean up a place to clamp the ground to, its faster and you get much cleaner metal, as long as you don't get carried away. The idea is to clean the metal, not grind it all away. Those magnet clamps work OK if the metal they get stuck to is bare steel, if its not bare steel, they don't work any better then any other clamp. I've also seen them get pitted on the surface that is against the metal, then they work like any other poor ground would. About the 3rd or 4th time cleaning up the contact pad, they don't work anymore, the pad can't make contact with the surface because the magnet holds the contact point away from the metal. They don't seem to last very long. After the 2nd one failed, I quit using them. give me a good ground clamp, or a pair of vice grips clamped onto the clean surface I can hang the ground clamp on.
There have been some good reccomendations for heavier clamps, and I have good clamps for my welders. That said, I have been attempting to build an aluminum oil tank, and there isn't a convenient way to hook a clamp AND hold the tank at an angle where I can weld it easily. Initially, I was able to clamp directly to the tank. Now that I'm welding the sides in place, I was relegated to just clamping the weld table and laying the tank against a propup to get a good welding angle. The surfaces of the vice and table are not clean and shiny but rather rust colored. The tank is small for power steering fluid, so not much weight to press down against the table or vice........yet it welded just fine. The aluminum is .100 thick and my machine is set for slightly over 100 Amps although I can't see the actual number while I'm welding. I know we all subscribe to the theory that "too much is just right" so a bigger clamp must therefore be better, but why does not using a direct clamp work fine sometimes???????
Sometimes all the stars and planets align and things that just shouldn't happen do. When those odd things happen, we probably shouldn't question why it worked, and just be thankful that it did. But we also shouldn't expect it to happen every time. I would have clamped a pair of vice grips onto a flange on the aluminum tank and then clamped the ground onto the vice grips.
Might want to check the welding wire on the spool. If it is old, it can develop a film or corrosion, causing a poor weld. Happened to me.
Gene, I agree that insuring you have a good ground is always my first consideration......but sometimes its just really difficult to get a clamp to co-operate with a decent welding position. I have found that getting a comfortable............no, make that "a doable" welding position has a big effect on getting decent looking welds. When I have to contort as I follow along the weld path, it usually shows in the weld quality. I will say that if the contact point of the lightweight aluminum tank moves slightly while welding it can produce a burned spot. What I learned from trying to make this tank is that while sitting it on the vise or table so it can be tilted to that weldable position, I probably should lay something like a heavier flat steel bar against it.....to prevent movement but to also add another point of contact. The tank is so light, that the heavy ground clamp weighs more than the tank, and then the heavy ground cable fights against getting the positioning I need. If I had one of those fancy welding tables with clamps, I could probably orient the tank any way I need and clamp it down. So I agree that a good solid connection is what to strive for, but sometimes you just have to make things work the best you can.
I made this thing up to get around difficult clamping issues. It's a beam hanger for things like lights and recessed ceilings. The clamping bolt is concave on the end and bites into the piece being welded. I just clamp my ground to it and weld.
The Jalopy Journal
