Welding or Plasma Torch on M1088 A1

[dwlindsey]

I'd like to do a bit of welding and a bit of plasma torch cutting on my M1088 A1

What do I need to do to avoid killing the ECU?

There are two battery cutoff switches. One under the dash that works a relay and a manual battery cutoff switch at the battery box.

If I cut out the battery using those switches, is that enough? Or do I need to disconnect the batteries completely, physically?

 

[GeneralDisorder]

Generally you don't need to do anything. Locate your ground near to where you are welding. If you happen to be really close to an electronic module that you think it may arc across then remove it completely.

Ultimately the current has to flow back to ground and a truck sitting on 47" tires isn't likely to be arcing to the earth so unless you have shore power lines hooked up there wouldn't be anywhere for the current to travel.

I've welded on hundreds of vehicles - exhaust much of the time which is connected directly to the engine. We never give it a second thought and it's never been an issue. If it was you would hear ALL about it from every person that has ever frequented an exhaust shop about how much they had to charge them to weld-proof the car before performing the repair.

The biggest issue is welding near flammable objects or fluids or fuel tanks. Pay attention to that.

 

[Ronmar]

What general said. And look for flammables under the truck as well. The battery cutout is fine, Keep your weld or PC ground close to your work. Ultimately your current path is from torch to that ground and back thru your equipment. Most mig welders run 30-40VDC. A plasma runs several hundred VDC but that arc is basically inside the torch head creating the plasma…

automotive modules are pretty robust and you would pretty-much have to pull current directly thru them to do damage. So if you are not welding on a module foundation or the wiring, and the battery connection is severed it would be very unlikely you could move any current thru them or build any dangerous voltages…

been welding on vehicles since the 80’s and have never seen one damaged…

 

[GeneralDisorder]

Also cover any glass or mirrors with welding blankets or they will be RUINED.

 

[swbradley1]

I've heard that you run the risk of damaging pretty much anything in the vehicle and cause mass whale beachings if you weld on a vehicle without disconnecting everything electrical. Been hearing that since I was a kid (69.9yo) and never understood why. Still don't.

Connect the ground and welld away. As said, cover anything you don't want damaged.

 

[dwlindsey]

I've heard that you run the risk of damaging pretty much anything in the vehicle and cause mass whale beachings if you weld on a vehicle without disconnecting everything electrical. Been hearing that since I was a kid (69.9yo) and never understood why. Still don't.

Connect the ground and welld away. As said, cover anything you don't want damaged.

I certainly wouldn't want to kill any whales . . .

 

[wjeeper]

I always disconnect the negative on the battery. (when i actually remember) Done lots of welding/ fab with it connected and disconnected, never had problems either way.

 

[aw113sgte]

The MTVR has a placard on the door specific to this. I went ahead and disconnected stuff just because risk vs reward. It was quick to do. I have welded on the FMTV without disconnecting anything and it was fine. That said, I was short circuit MIG - I've heard HF TIG can potentially fry more stuff. Seems like risk is low, reguardless - just have a good spot for your ground that is close to where you are welding.

 

[swbradley1]

Is that for just the truck you are welding on or every truck within 100 miles?

 

[GeneralDisorder]

That's some clipboard warriors idea of a CYA. Someone, somewhere did something really stupid like clipping the ground to an electronic module housing directly. This is the result I'm guessing. That or litigation that went sideways because lawyers and judges also don't understand electricity in general.

 

[Ronmar]

Naw, that's clearly a typo... That is all the stuff you must disconnect before the nuke hits...

 

[GeneralDisorder]

Naw, that's clearly a typo... That is all the stuff you must disconnect before the nuke hits...

True that. The "shielding" that people think is for EMP is not for the truck. It's so the truck doesn't interfere with coms and other military equipment such as high powered radar for missile systems, etc and so they don't suck the life energy out of all the truck computers. If they were worried about this garbage surviving a nuke they would be fully sealed for NBC. What good is a contaminated truck with dead operators?