Arc Wedling?

[Jehu]

My friend who wanted to pop rivet a pice in my rotted floorboard scolded me when I said I had a guy who was going to weld the pieces in. He said: "Your car has sensative electronics in it ,never arc weld in it .." Would you get a strong enough weld with what you can do with just a blow torch? I didn't ask the body guy what he planned to do. How must this job be done? I think he mentioned 3/16the sheet metal but was busy till first week of September so i didn't ask many questions.

[attack eagle]

tell him to go smoke another bong pipe.

If you are really worried, disconnect the negative terminal of the battery. Done.

People weld exhausts all the time... If that was the case you could never repair a car built after 1969.

[Jehu]

That's what I said. He said there were other points via which current could travel to fry things....saying "How do you think arc wleding works? he clips a ground to the chasis of the car... one short and zap... well onward and upward..

[Bill R.]

row easy enough to get to. Then disconnect the battery and when welding it attach the welder ground as close to the area your welding as possible. I would not use a oxy acetylene torch, i would use a wire feed welder, like a millermatic 140

My friend who wanted to pop rivent a pice in my rotted floorboard scolded me when I said I had a guy who was going to weld the pieces in. He said: "Your car has sensative electronics in it ,never arc weld in it .." Would you get a strong enough weld with what you can do with just a blow torch? I didn't ask the body guy what he planned to do. How must this job be done? I think he mentioned 3/16the sheet metal but was busy till first week of September so i didn't ask many questions.

[Jehu]

row easy enough to get to. Then disconnect the battery and when welding it attach the welder ground as close to the area your welding as possible. I would not use a oxy acetylene torch, i would use a wire feed welder, like a millermatic 140

Thanks. I considered that removing the DME would be smart... what about unplugging the Radio?

[Bill R.]

never been a problem so far.... Bmw and other manufacturers also state to pull the computers if you have the car painted... The idea being that the heaters in the paint booth would raise the temp high enough to damage the computers.... I don't think they do that here in Arizona though as i've never seen one fail after a paint job.

Thanks. I considered that removing the DME would be smart... what about unplugging the Radio?

[attack eagle]

I'd ask him if he was going to weld the body of the car or connect his ground to the computer.
Electricity is not going to jump an open relay to get into the DME because there is no Potential there ther is no where for it to flow to, it is off dead raising the ground potential when viewed from outside the vehicle, does not affect the fact that you haveto have potential ABOVE THAT GROUND for current to flow.
The ground is the BODY, and unless you have left a ground from the welder to the dme chassis, and failed to ground the welder, all the current is going back to the welder thru the body. Hell fire, you have 6-8 mini arc welders on your engine, and no one worries about them firing a spark to ground and it burning out the ecu...

If this wasn't the case, the lightning bolts coming out of the ground would get us if we walked barefoot, right?

[Ferret]

I'd ask him if he was going to weld the body of the car or connect his ground to the computer.
Electricity is not going to jump an open relay to get into the DME because there is no Potential there ther is no where for it to flow to, it is off dead raising the ground potential when viewed from outside the vehicle, does not affect the fact that you haveto have potential ABOVE THAT GROUND for current to flow.
The ground is the BODY, and unless you have left a ground from the welder to the dme chassis, and failed to ground the welder, all the current is going back to the welder thru the body. Hell fire, you have 6-8 mini arc welders on your engine, and no one worries about them firing a spark to ground and it burning out the ecu...

If this wasn't the case, the lightning bolts coming out of the ground would get us if we walked barefoot, right?

It's not like there's going to be an electrical static issue either, most welders run in the 1V range, though the bigger ones have been known to hit the amazing highs of 4-5V while actually arcing.

With regards to the painting comment above - painting a car tends to build up a massive static charge on the car as the atomizing process tends to transfer charge into the paint from the nozzle. You *can* fry electronics because of it - but you'd have to be sticking a screwdriver in some pretty dumb places for that to happen.

[Bill R.]

factory service manual, tell me which parts your having a hard time understanding and i'll attempt to explain it to you.... Oh and control units loosely translates as computers, you know, DME, SRS,ABS etc

[Jehu]

factory service manual, tell me which parts your having a hard time understanding and i'll attempt to explain it to you.... Oh and control units loosely translates as computers, you know, DME, SRS,ABS etc

OK,I am assuming the guy I plan to have do this job is an experienced professional body restorer. There are a half dozen big old antique Mercedes Benz's in the yard he's restoring as well as other modern cars and from talking to him he presents himself as a quick minded individual. That being said I will be asking him to rehab the hole thru the floorboard directly under the base of the accelerator pedal. He removed the pedal and saw how the two tabs on the base piece had been welded on to the floorboard and that he would weld a piece over the cleaned up original and weld the pedal base piece to that . I will discuss with him somehow fitting another piece from below the hole to prevent the Elements from affecting the space between the new covering piece and the original floor THRU the opening if it is only covered from above inside the car. The exhaust pipe off the header goes directly under this hole and dropping the entire exhaust is something we hope to be able to avoid. I was wondering if it will be possible to weld a piece placed from beneath slipped in under the exhaust pipe and held in place by some means to be welded along the rim through the hole from above FIRST then weld the top piece over that effectively sealing out the elements from entering via the otherwise open underside? That being the plan,knowing the area where he will need to work,providing the seats will be removed,center console out and carpet folded back Would you expect he will have the place to ground within the Three Feet instructed in the manual there Meaning if he will we can proceed safely with just removing the negative battery cable and the DME and other Control units in there and I suppose the CCM and LKM over in the Fuse Box should come out too.

On a side note my Radio turned up fried after I had my Car painted. The shop acted completely puzzled about the possible cause and never really offered to do anything for me. I ended up just buying another off ebay for $120..