I've got Tuesday off work again, and have decided that I'll go by a friend who has an arc welder and get one annoying noise removed from my car.

There is a cracked weld to the rear of that perforated heat shield thing that goes over the catalytic converter, and during acceleration, or whilst idling (which is not the smoothest), there is an annoying metallic noise. If I get under the car whilst the rattling is going on, I can press directly against the cracked weld and the noise stops, so I'm fairly sure of my diagnosis.

What precautions do I need to take, to avoid the arc welding process frying some of my car electronics ? I'm assuming that my friend will clamp his welding lead somewhere on the exhaust close by the area being worked on, so the current flow should be in a fairly self contained loop in the exhaust shouldn't it ?

Aside from maybe disconnecting the car battery (?), is there anything else I could / should do ?

John Marshall
1994 940GL wagon
Christchurch NZ