Do I just disconnect the battery? Or is there other stuff I have to remove/disconnect? Hopefully this isn't a nightmare.. I have no idea how many ground straps are in the car

I'd imagine "just" the positive wire from the battery would do it, since all the positives come down to one point- right??


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

 

You shouldn't have to disconnect anything. Used to be, when cars had points in the dist., you had to pull the points out because they would weld themselves together when you welded on the car. I have done ALOT of welding on my car and have never had a problem.

 

Disconnect negative batt terminal for safe measures, IMO...

 

I always got concerned about the gas-tank, adjacent fuel lines, nitrous tank, etc. exploding from picking up a "stray" current.

Please take every safety precaution available, a "blown-up" human body is not usually repairable.

Unless you are 100% comfortable with welding, take the car to an approved (and insured) shop to get it done.

If you plan to do it yourself:

Ensure you have a ground cable connected to the immediate-area you are welding on the car.
...i.e. if weldeding in subframe connectors, place the ground-clamp directly on the part of the car's subframe near the weld joint. The other end of the ground goes to the ground terminal on the welder.
The welder should be grounded to the "earth" or the ground soil by a 4' copper "earth-ground" rod, available at Radio Shack ($6). If your welder is in the garage w/a cement floor, drill through the cement with 1/2" dia. masonary drill, into the dirt. Pound the earth-ground thru the drilled hole & clamp a ground-wire from the machine to the earth-ground rod.
If that's not available, the welder should be grounded to an electrically-conductive structure in the building(I-beam, plumbing,
etc.,)which ultimately contacts the ground (earth).

The earth-ground rod is a much better method, and your welder performance will be much better.

 

So there's no need to unhook the computer or radio or injectors or etc? I thought the high voltage could screw those things up?

G92Joe, where would I connect this ground rod to the MIG welder? To the case? To the welder's ground clamp? I have my earth-ground for my 18 foot cb antenna's lightning rod, I suppose I could use that.

Heh, I never thought about what spare current could do to gasoline.. I always thought it was the welding sparks that could cause problems! Is that what this ground rod prevents?

The welding (for now) will be done near the hood latch.. the supporting sheetmetal under the latch cracked somehow, and it's tilting the hood latch mechanism. Popping the hood has now become a 20 minute project


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

 

Yes, the earth ground gets connected to the ground terminal on the welder.
As long as the + cable is off the battery,
AND the car is grounded to the earth ground (by the ground cable) or equivalent, all elec. components on car are safe.

 

I've never disconnected anything...I just fire up the wire feed and lay it down.

Never had a problem.

Now, if you want to tack weld the ECM to the firewall, you might have a problem.

------------------
ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited September 26, 2000).]

 

I have an arc welder, but I've welded on the car without disconnecting anything lots of times.

 

Tom,

IN theory, you shouldn't have to disconnect anything. However, to be completely safe you might want to disconnect the positive battery cable and jump it to the negative cable. This will prevent any contingent of the higher arc-establishing voltage from raising the potential of any component more than the resistance of the component would drop the voltage in normal use - in other words nothing should be exposed to more than 12-15v if something goes wrong with the work clamp and the voltage "floats up" on the vehicle.

That being said, you should also make certain your work clamp (welder ground connection) is firmly attached and as close to the arc as practical. This should minimize any stray voltages.

------------------
Later,
Vader
------------------
"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Vader is right about grounding the welder as close to the work as possilble. Welding is not any different from any other type of electricity - it takes the shortest easiest route. I know a guy that grounded a welder to the engine in his Powerstroke Ford when he repaired his fifth-wheel hitch. He arced the piston rings to the block - not cheap!

 

LOL @ Engineboy!

Great- thanks again guys! Good to know I won't torch my whole computer system


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards