Old Library

Dave,

Disconnect the battery short the battery leads from the car together (NOT
The Battery). This trick provides a direct ground path on the electrical
system and helps negate induced current from the action of the welder. Make
sure the ground clamp of the welder is as close to the weld site as
practical to minimize loop currents.


--
Regards,
Bill Gallas

73  Type 181
74  Type 181
77  Porsche 924
88 Fox Gls
92 Jetta GLI 16V 2.0
"DaveRChey" &lt;&#100;averchey&#64;cs<img src=/i/dc.gif border=0 width=35 height=15>&gt; wrote in message
news:&#50;0010319121358.13273.00002123&#64;ng-fq1.news.cs<img src=/i/dc.gif border=0 width=35 height=15>...
> Are there any special procedures when you're welding on a car?  Does the
> battery need to be disconnected? Car running? I'm using a stick welder and
I'm
> afraid of damaging the electronics.
>
>
> Dave / Aspiring Welder
> '00 Passat Wagon 30v
> '84 Rabbit GTI 16v 2050cc

William Gallas wrote:
> 
> Dave,
> 
> Disconnect the battery short the battery leads from the car together (NOT
> The Battery). This trick provides a direct ground path on the electrical
> system and helps negate induced current from the action of the welder. Make
> sure the ground clamp of the welder is as close to the weld site as
> practical to minimize loop currents.

I done everywhere from nothing to disconnect everything.  On my 4WD, I have an
on-board welder/alternator and have used that to weld on the truck while the
engine is necessariy running.  Have also used the dual batteries on-board
(disconnected from the vehicle) connected in series to weld on the same
vehicle.  When I use an external welder on it, I usually try to connect the
ground clamp to bare metal close by where I'll be welding.  I generally try to
use DC, electrode positive so at least its the same polarity as the battery. 
I hadn't tried shorting the battery cables, sounds like a good precaution.