Welding precautions

[skoller]

What precautions do I need to take with the vehicle electrics,especially the ecu, before I do some welding on my Puma.

[isuzurover]

Usual practice when welding on a vehicle is to disconnect the battery.

[Carnut1100]

Also a good idea to disconnect the alternator and on vehicles with an ECU it is best to disconnect it as well and physically remove if possible.
Our buses at work has warning labels to remove the auto gearbox controllers before welding....

[justfishing]

Hello,
Depends where you are welding always have the earth next to where you are welding, it might be good practice to disconnect the battery, as already said. When welding on my D2 I have never had any trouble I haven't disconnected anything, as my earth clamp is on the piece being worked on.
Ian

[Summiitt]

Just disconnect the battery, welded plenty on my puma with no issues.

[flagg]

I know it goes without saying but make sure you clean up the area really well so there is nothing that can catch fire or be damaged behind the weld area. Even oil from your fingers will contaminate the welds.

[austastar]

Hi,
I was getting paranoid about this, but I think the manufactures are just wearing their legal tin pants.
I was making enquiries about a mod on the exhaust system from a local specialist, and asked about what precautions they would take if they undertook the job.
They don't even disconnect the battery, just keep the earth clamp close to the weld point, no matter how high tech the vehicle.
This is not with your average stick welder of course, they would use mig, and I'm not sure what the different electric effects would be.
cheers

[Rick Fischer]

Hi,
I was getting paranoid about this, but I think the manufactures are just wearing their legal tin pants.
I was making enquiries about a mod on the exhaust system from a local specialist, and asked about what precautions they would take if they undertook the job.
They don't even disconnect the battery, just keep the earth clamp close to the weld point, no matter how high tech the vehicle.
This is not with your average stick welder of course, they would use mig, and I'm not sure what the different electric effects would be.
cheers

There is also a cheap gadget from Repco et al, which as I recall clips to one of the battery terminals to kill the eddy currents. Disconnecting the battery will not stop the eddy current induced by welding.

On an exhaust pipe, apart from the manifold, it is insulated from the body therefore the eddy current is only in the exhaust pipe. Wouldn't push my luck anywhere else. Only needs a "spike" to be induced into the ECU wiring somewhere! Spikes don't care if there is no earth, they find one - make one!

With things like this one might get away with 99.9% of the time. However, what is the result if the one in a thousand is at 1 or 2 or 3? You then have a clear run for for the next, at least, 450 to 500 times

Or maybe not, you could end up with perhaps a clear run for 1200 to 1500 or maybe 3000.

Damn lies, statistics, probabilities, and standard deviations to the left !

Cheers

RF

[flagg]

The current will only flow between the torch and the the earth clamp. If there is any other path for the electrons some very odd is going on! (Like when you are doing something small on a bench and move it in a way that puts your arm in the path.... haha i guess i only did it once :-S)

[Rick Fischer]

The current will only flow between the torch and the the earth clamp. If there is any other path for the electrons some very odd is going on! (Like when you are doing something small on a bench and move it in a way that puts your arm in the path.... haha i guess i only did it once :-S)

Unfortunately, it isn't that simple. The welding current may flow between the torch and the earth. However, that doesn't account for the eddy currents that may be induced elsewhere in the structure, and may wish to get to an earth.

Every time the magnetic field generated by the welding current collapses ie break the arc, a current is generated in adjacent structure/wiring. lts the "how strong", and the "how high the voltage" that is the problem.

Cheers

RF