Welding a welder

[roofman]

I want to weld a ring on the rear base of my Safmig for a Co2 bottle...will it be ok to use that paticular welder to do it or is there a risk of frying the PCB with its own current?

 

[Shedendman]

I had to do a little repair job on the casing of my oxford 180-1 T using the same machine never had a problem afterwards

 

[Richard.]

I think you should be ok to do it but it's very very important to direct earth. (Keep ur return clamp as close as possible to the arc). I would actually earth on the steel your adding to the machine rather than the machine itself. Last thing you need is current going through the internals. Also make sure you leave the covers on the machine while you do it.

 

[Kent]

Can it not be mechanically fastened

 

[Dimitri De Spiegeleer]

I would advise against welding, as you'll connect both sides of the transformer (primary has the chassis ground, secondary will be your ground clamp on the frame) to each other.
Recipe for fried electronics.

either by bolting, as Kent said, or oxy-fuel welding.

Can't you strip the machine, so that the bottom part is completely isolated from the electronics? That's another possibility.

 

[skotl]

I would advise against welding, as you'll connect both sides of the transformer (primary has the chassis ground, secondary will be your ground clamp on the frame) to each other.
Recipe for fried electronics...

I'm not sure about that. When you're welding a work piece the current flows through the piece, through the earth lead and back to the welder's chassis anyway, so what's the difference when applying the arc to the chassis?

(mind you... I'm assuming that the earth lead is connected to the welder's chassis - what I've written is probably rubbish if it's not)

 

[Dimitri De Spiegeleer]

The earth lead is not connected to the chassis. check this with a multimeter on ohms/continuity. The secondary is a fully isolated circuit.

 

[Kent]

All I might add is have you never left something on the bench while welding something (like a steel rule) and had it arc to the bench

 

[roofman]

All I might add is have you never left something on the bench while welding something (like a steel rule) and had it arc to the bench

this is why i never weld something iff possible held in my vice jaws and the earth on the casting...arcing on the screw and block cant be good for them. Ok thanks for the replys lads, ime going to make the ring and weld 3 flat lugs on the bench then bolt it to the welder...cheers

 

[thinfourth]

On the other side of the coin

I have a steel framed workshop, with a steel bench connected to the steel frame and another steel bench connected to the same frame with a big copper strap

All the electrics are earthed to the steel frame

Steel frame is earthed to the earth

I weld on bench 2 by attaching the return line of the welder to one bench

And that bench being directly connected to earth


No loom smoke has escaped any welder so far.

 

[Richard.]

We all know leccy is lazy and will take the shortest route home. If we can think about this before connecting the return clamp it limits potential risks of that current been transferred though sensitive components. I've welded on welding machine chassis before with no issues and it's simply down to clamping my return inches from my arc.