arcing to job??

[johnakay]

when I'm welding ,the piece that I'm welding arced to the bench and this leaves a burn mark on the tubings.
is this due to poor earth?
I have a sheet of aluminium bolted to my bench this was done to help eliminate scratches to the tubing.
so is this an earth problem or should I be looking at some thing else?

 

[Welderpaul]

Is your earth clamp on the bench? The current will jump the gap and leave a mark where it has done so. Stick the earth clamp on the tube and set the tube on something non conductive.

 

[gordon stephenson]

For materials you do not want to mark with the earth clamp or arcing to the bench top,Strip the multi strand copper cable from inside a spare 2ft length of earth return welding cable, then wrap this a few times around your job to be protected and earth clamp on to the free ends.