Thread: welding and disconnecting batteries

Originally Posted by weeds

is it required

had to drop into an exhaust place to have some warranty work done after they removed the muffler and resinator. all four cars that were driven on and off the hoists including mine while i waited didn't have there batteries disconnected prior to welding

normally when i do any welding i disconnect the battery

maybe they have special welders!!!!!!

i was expecting to have to pay a few $$$ as where the exhaust cracked was just before there work, quite suprised when i went ot pay they so no charge

rob bliss exhausts

i always thought it depended as to which type of welder you were useing. I would say definatley disconect the battery on a mig welder , but gas welder then i don't know, but can't see why you would have to

IMOH FWIW,

DC welding isnt too bad for not disconnecting the battery be it arc mig or tig
AC welding is bad juju

but I prefer to play it safe. disconnect battery earths make sure the earth clamp is a close as practicable to the weld and make sure the vehicle is grounded from multiple points if achievable.

Did they put a supressor clamp on the battery? This way you don't have to disconnect it.

Originally Posted by shaunp

Did they put a supressor clamp on the battery? This way you don't have to disconnect it.

nah, just clamped straight onto the exhaust

dont worry...its pretty safe......

the exhaust is isolated from the car by the rubber hangers......it is connected to the engine which is earthed out through earth straps......

the welding they do on the exhaust wont cause any hassles.....i dont think they could afford to stay in business if it damaged ecus......

the electricity looks for the shortest and easiest path to get to where it wants to go......
in this case its between the clamp and the electrode......which as you saw...they placed pretty close together......

if they placed the clamp on the chassis and then tried to weld the exhaust....you would have all that current flowing through everything....
all over the vehicle and all the circuits......trying to get from the chassis to the exhaust.......this way would definitely fry a few bits.........


dont worry....they know what they are doing.......but then again.....yes...its always safer to disconnect the battery......but only as a precaution......

I even disconnect my alternator, just to be sure, to be sure.

Shorty.

Originally Posted by shorty943

I even disconnect my alternator, just to be sure, to be sure.

Shorty.

if you go to all that trouble.....you should also be unplugging the ecu as well if you have one.....
its the most expensive part of the electronics to replace......

Welding gets down to the shortest path the charge gets to earth.
If you are doing any welding make sure the earth clamp is plugged and earthed properly as close as possible to the job.
My first strike with the mig handpiece is on the earth clamp,then across to the job.OK eventually I will need to replace the earth clamp due to abuse,but Im not a welder for a living but can weld pretty good.
Andrew