Precautions before welding a 4200...?

TimR

Member
Messages
2,656
Basically I want to minimise potential damage to electrics from welding on the car..
Presumably, isolating the electrics via the boot switch AND disconnecting the battery is all that's required Id have thought, or is there something I need to know before I blow up expensive ECUs end such..?
cheers
 

2b1ask1

Special case
Messages
20,220
Good Earth on the welder as close to the weld site is best practice, even consider double earth straps either side of the job.
 

Gp79

Member
Messages
1,393
Basically I want to minimise potential damage to electrics from welding on the car..
Presumably, isolating the electrics via the boot switch AND disconnecting the battery is all that's required Id have thought, or is there something I need to know before I blow up expensive ECUs end such..?
cheers

what part are you welding?

I had a subframe repair done before I had time to replace with no issue.

as above battery off and good earth as close to repair as poss
 

Oneball

Member
Messages
11,075
Make sure your earth is connected to the same bit of metal you’re welding. If youre welding the subframe connect it to the subframe not the body or suspension arm.
 

Oneball

Member
Messages
11,075
have a couple of fire extinguishers to hand would be my advice

You don’t need an extinguisher just make sure you’ve got a beanie over your locks.

Was picking up a rollcage from a place in Dudley about 25 years ago. Guy turns up in a mk2 Escort and as he gets out smoke starts coming out of the bonnet. He opens it and the carb is on fire so he starts trying to blow it out at which point his dreadlocks go up with a whompf, we were rolling around in hysterics. He did manage to blow it out though.
 

lifes2short

Member
Messages
5,821
A large welding blanket is a good thing to have as well, helps with avoiding spatter and sparks getting to other parts/bodywork etc
 

mjheathcote

Centenary Club
Messages
9,033
Good Earth on the welder as close to the weld site is best practice, even consider double earth straps either side of the job.

Double earth is a good call.
At work when welding on stainless steel process plant with various CPU's nearby, you can't be too careful!
 

midlifecrisis

Member
Messages
16,102
What Newton says, if you think about it, electricity will always follow the easiest path to earth. If you put earth straps either side then the current from the welder will go straight to earth rather than the rest of the car. But as an extra precaution, disconnect the battery and use the isolator.