Welding Car Damage Computer. But you said Just bought my first welder a Hobart 125 Flux Core implying that you are new AND you have a 110v machine. Speculation runs rife regarding whether the negative terminal of a vehicles battery should be disconnected before welding on that vehicle.
If this weld is close to a delicate system such as a computer you might have problems but odds are very high that nothing bad would happen. The most important aspect of TIG welding on a modern car is protecting the cars ECM and digital electronics which can otherwise be damaged by the high frequency generated during the TIG welders initial voltage spike while starting an arc. I have been told that TIG welding on cars that have computers can damage the computers.
How long would it take to disconnect a battery vs how long would it take to troubleshoot diagnose and replace blown units.
Surge in power from the battery causing it to become damaged. Preheat the area around the weld to around 300 degs. This computer is essential to your car functioning and you would not be able to drive if the ECU becomes damaged or destroyed. The reason to do it is that it helps to prevent damage to the vehicles ECU and other electronics.