I should add that make sure the return clamp is attached close to the work , as a thin ground somewhere in the muffler may melt if there is one..Leave the battery connected as it acts as a dampener/surge protector.
In 20 years I have ad quite a bit of welding done electric welding done on my Westfalia, with no problems.Robert1982 Westfalia

      From: Steve Williams <steve@WILLIAMSITCONSULTING.COM>
 To: vanagon@GERRY.VANAGON.COM
 Sent: Tuesday, September 1, 2015 9:26 PM
 Subject: Welding on Van - ECU consequences?

Hi,

I am taking my van in tomorrow for a bit of patching on my exhaust system.

It suddenly occurred to me that they may be using an electric welder on
my vehicle rather than a gas welder.

Is it recommended/mandatory to unplug the ECU if electric
(arc/mig/tig/etc) welding is being done on a 1991 Westfalia?

Thanks,
Steve W.