Welding on my car with electronics HF TIG

jasonz28camaro · Mon Apr 20, 2015 6:38 pm

I plan on welding some small tabs on the rear frame of my car for an anti roll bar and I just sold me MIG welder so I'll be using TIG.

I'd like to use HF start and weld in DCEN, is this really bad for my electronics, wires and ecu? I Have the ability to use scratch start but would rather use HF.

Will a clamp on surge protector instslled on the battery help?

Let me know what you guys think and some options. Thanks.

I'll be using an Everlast 250ex

rick9345 · Mon Apr 20, 2015 7:39 pm

clean ground/work connection close to weld.
I also add a static strap from frame to earth(floor) for good measure, like a hunk of chain

Mon Apr 20, 2015 8:18 pm

Disconnect the battery ground cable... Wait at least three minutes for the capacitors in the air-bag circuit to discharge, and (as stated above) keep the ground clamp as close to the weld as practical.

Steve S

jasonz28camaro · Mon Apr 20, 2015 8:25 pm

Thanks guys!

So do in not need to worry about the high frequency start?

GreinTime · Mon Apr 20, 2015 8:29 pm

Nah man you'll be alright, although I'm sure someone will comment at some point before this does off that you can ruin your ECU by looking at it sideways when welding on your car

If you don't have a path to ground, then the car is not grounded. You would have to jump a serious arc to close the gap between your negative battery cable and the battery to cause any damage.

raticus · Sun Jun 14, 2015 6:39 pm

ok this post is a bit old but thought I'd throw my two bits in... as far as any arc welding on a car, I was especially paranoid doing it on my race car, so I made sure that all my ground wires on my car go to a single ground strap terminal (around 40 ground wires), and that ground strap goes to one single wire straight back to my battery's negative terminal. When I weld, I just disconnect the one wire at the battery and weld away without too much fear. I still try to always put my welders ground strap as close as possible to the weld area, and try to stay away from bearings, but at least I don't have to worry about frying my ignition box, etc.

Captainbeaky · Mon Jun 15, 2015 12:34 pm

I'm an electronics engineer - have designed car and earth moving machinery ecu's for jaguar, Landrover and caterpillar for 20 plus years.

Ecu's already have some hardening built into them for static etc, but it's not a great idea to muck about and rely only on this...

Disconnect the battery ( or batteries in some cases!), get a good solid Earth on the part you are welding, and you will be ok.

If you are welding particularly close to a harness or component, disconnect or move it if you can.

The biggest danger is of a current being induced in a vehicle harness, damaging an ecu, so getting a good ground local to the weld is a good idea - it reduces any volts drop in the vehicle shell that could cause a problem.

Also pay attention to your welding cables too - don't lay them alongside a vehicle harness ( for example, if you are welding inside the vehicle,) Don't coil them inside the vehicle next to vehicle harnesses have any spare coils of cable outside the vehicle.

Ultimately, if you are doing extensive mods to a car, it's a good idea to disconnect the ecu's and remove them from the car anyway - just in case you damage something.

Cheers,

Mike.

kiwi2wheels · Mon Jun 15, 2015 5:47 pm

Even when you have disconnected the battery, are there some components that could be damaged by start/continuous HF, if the component/s still have the loom/s connected ? I'm thinking sensors, triggers, etc , apart from the ECU.

I'm a believer in a gram of prevention is worth a kilo of cure......

R0gueSp3ctre18 · Thu Jun 25, 2015 3:21 pm

Captainbeaky wrote:I'm an electronics engineer - have designed car and earth moving machinery ecu's for jaguar, Landrover and caterpillar for 20 plus years.

Ecu's already have some hardening built into them for static etc, but it's not a great idea to muck about and rely only on this...

Disconnect the battery ( or batteries in some cases!), get a good solid Earth on the part you are welding, and you will be ok.

If you are welding particularly close to a harness or component, disconnect or move it if you can.

The biggest danger is of a current being induced in a vehicle harness, damaging an ecu, so getting a good ground local to the weld is a good idea - it reduces any volts drop in the vehicle shell that could cause a problem.

Also pay attention to your welding cables too - don't lay them alongside a vehicle harness ( for example, if you are welding inside the vehicle,) Don't coil them inside the vehicle next to vehicle harnesses have any spare coils of cable outside the vehicle.

Ultimately, if you are doing extensive mods to a car, it's a good idea to disconnect the ecu's and remove them from the car anyway - just in case you damage something.

Cheers,

Mike.

Hmmm. Sound advice. I never thought about the cables being near other harness affecting electronics. Makes sense, high voltage cross talk or induction would be devastating to a low voltage ecu circuit. Thanks for the information.

Captainbeaky · Thu Jun 25, 2015 4:14 pm

Yes, it's important to think where your cables go, not just what you are welding.

If you can, it's safer to disconnect everything, but it's not really possible on many cars - or simply takes too long.

Disconnecting the battery, and getting a really good local earth provide the biggest reduction in risk you can get.

If you are welding anywhere near an electric harness, then shield it or move it.

And watch your cable run - keep it away from vehicle harnesses.
( that goes for the earth too!)