Disconnect the battery?

[Trip59]

Small project tomorrow morning, radiator support cracked on my friend's Peterbilt, down at the bottom where the hood strut bolts to. It's not that thick, not worried about the weld itself even though I'm stuck using the small Hobart I have, my question is, do I have to worry about onboard electronics at all?

[Rambozo]

Small project tomorrow morning, radiator support cracked on my friend's Peterbilt, down at the bottom where the hood strut bolts to. It's not that thick, not worried about the weld itself even though I'm stuck using the small Hobart I have, my question is, do I have to worry about onboard electronics at all?

Since no high frequency, there is a lot less danger. Most devices have labels that caution you to disconnect the battery when welding. Some things like MSD modules require they be removed before welding. It's never a bad idea to disconnect power before welding, but I can't say that I always do. The big thing is to make sure you have your ground clamp as close as possible to the weld, and to make sure it's a real good connection. Otherwise the ground path might go through things that won't like it.
I saw a guy welding a body panel on an MG midget, where he had the ground clamp on the frame. Everything went fine until he tried to move the car later. It seems that the welders ground path went via the choke cable and welded it solid.

[Rodsmachineshop]

make sure disconnect battery cables and ground frame to earth or will damage ecm . i even unplug ecm connection if easy to get at , don't want to fry a diesel ecm very expensive . when i weld on later cars i do them on my car lift or use a floor jack since then has a good earth ground and keep ground clamp at close to what you welding . what funny was welding on a ford car installing a hitch ever time i welded the fuel pump in the tank ran even with the battery disconnected lol couldn't think why that would happen ,

[Trip59]

Appreciate the info! Wasn't sure, being where it was and what I was welding it with, but I was concerned enough to ask... glad I did! Oddly, we noticed it not too long after we were talking about the sticker on the frame warning not to weld or drill the frame as it was heat treated.

Have a few parts of the cooling system to do once I get the TIG in, several bungs to install on a couple of 90* rigid elbows, then there is the trailer to repair some areas in the floor and walls. No spool gun, so I'll be TIGging those as well. This is the only repair actually ON the vehicle. Well, other than a ton of wiring work I've done for him. Interestingly enough, I'm also making a jack base/positioner tomorrow as well for the same guy. Should be a productive weekend if the weather holds out.

[fdcmiami]

Appreciate the info! Wasn't sure, being where it was and what I was welding it with, but I was concerned enough to ask... glad I did! Oddly, we noticed it not too long after we were talking about the sticker on the frame warning not to weld or drill the frame as it was heat treated.

Have a few parts of the cooling system to do once I get the TIG in, several bungs to install on a couple of 90* rigid elbows, then there is the trailer to repair some areas in the floor and walls. No spool gun, so I'll be TIGging those as well. This is the only repair actually ON the vehicle. Well, other than a ton of wiring work I've done for him. Interestingly enough, I'm also making a jack base/positioner tomorrow as well for the same guy. Should be a productive weekend if the weather holds out.

all i can say is everyday, from one corner of the country to the other welding is being done on the backs of trucks. how many field fabricators disconnect their batteries to weld something. searching the net for instances of damage done from welding is like trying to find that mythical welder who had the cigarett lighter explode in his shirt pocket.

anyway, since it is considered a fact by so many you will be doing yourself a favor by just having the owner disconnect them otherwise if there is so much as a flat after you are done, it will come back at you. i did some repair work on two rolloffs yesterday; the owner said he was going to disconnect the batteries. do you think i argued the point? not hardly.

[Rambozo]

all i can say is everyday, from one corner of the country to the other welding is being done on the backs of trucks. how many field fabricators disconnect their batteries to weld something. searching the net for instances of damage done from welding is like trying to find that mythical welder who had the cigarett lighter explode in his shirt pocket.

anyway, since it is considered a fact by so many you will be doing yourself a favor by just having the owner disconnect them otherwise if there is so much as a flat after you are done, it will come back at you. i did some repair work on two rolloffs yesterday; the owner said he was going to disconnect the batteries. do you think i argued the point? not hardly.

Properly designed electronics should have no problem, but there is the risk that they are not properly designed. My own stuff, I weld on all the time, occasionally with them running, even. Considering that some ECM's die for no apparent reason, in some ways it makes sense to reduce the risk. Having said that, just disconnecting and reconnecting the power is something that can take out a weak component. Of course the costumer will point the finger at you, no matter what. There are no guaranties in life.

I have had an MSD on a race car go bad from welding, but that was a high frequency issue, and a very old and abused MSD.

Oddly, we noticed it not too long after we were talking about the sticker on the frame warning not to weld or drill the frame as it was heat treated.

Many years ago I wish I had taken a picture of a semi frame that had such a warning stamped right into the aluminum frame. It had been converted from a tractor to a dump truck, and there was a beautiful weld bead right through that notice, where the frame had been extended.

[Trip59]

Many years ago I wish I had taken a picture of a semi frame that had such a warning stamped right into the aluminum frame. It had been converted from a tractor to a dump truck, and there was a beautiful weld bead right through that notice, where the frame had been extended.

Well, I had to explain to him that it COULD be welded, but it would have to be done properly and other steps would need to be taken. I'll have him disconnect regardless. There's also the case of proper vs improper installations... who knows on that one. Better safe than sorry.