Hi all, hoping everyone is good.

Looking for some help please in simple language, I have a cheap mig gasless welder that I am trying to get to grips with the polarity of the gun and earth clamp.

I have a multimeter to check but I am not sure of what I am to look for. If the gun has to be neg then what should the meter show? How do I set the m/meter up and do I have the welder switched on?

I only have the welder as payment and hope to try my hand at some welding at home.

I have read what I can but still confused, all help gladly received.

Thanks all Barrie

Hi,

You don't need a multimeter for this.

The clamp just completes the electrical circuit.

So if you're only welding one piece of metal, the clamp just gets placed on that piece of metal.

It does get a bit more complicated when working on a car. As you have to make sure the clamp is on a thick piece of metal. And also that there aren't any sensitive electronics in between the gun and the earth clamp. It is possible for the electricity to spike electronics if they are located in the path between the gun and the clamp.

I've always disconnected both Battery Terminals when Mig welding cars, it may or may not be over the top but I felt safer and make sure you have a charged up hose on standby in case you set the car on fire.

I've never used a Gasless MIG, so I've no idea how suitable they are for cars.

Hi all, thanks for all your help.

What I was really asking is how does one confirm the polarity of the ground and positive terminals of a flux-cored welder, ie, is the gun positive or negative as I have it at the moment.

For many years, (63 yrs) I have used stick when welding and have read up on flux-cored welding but want to make sure I have the polarity correct. Something to do with connecting a m/meter to the gun and ground.

Thanks all Barrie

I'm surprised they are not marked or colour coded.

Indeed. Sounds very strange. Can you post a picture of your welder?

Generally a polarity test should be done on the voltage setting. Welder will need to be switched on to provide voltage. Probe both terminals. If the voltage shows as + then your red probe is on the positive terminal. If it shows as - then your black probe is on the positive terminal.

Hi all and Tom. Can't put up a pic as welder at garage. It is only a very cheapo 130, could that be amperage? Tom you have just explained in simple (that's me) language of how to check. I can now paint positive terminal red.

Thanks all

ps' I have just purchased a new Titan power washer from Screwfix and needed a converter for the water pipe which is a push fitting, to 22mm gun fitting and the one needed is the Nilfisk adapter, hope this helps someone.

Barrie