Welding with a magnetic earth clamp.

[terravista]

Greetings
I am a bit of a hack when it comes to electric arc welding, and often have trouble maintaining a continuous weld. I have been told the quality of the earth is extremely important, but that can be difficult with dirty/rusty/painted steel combined with the pathetic clamp on the budget priced welder.
Does anyone have experience with the magnetic earth clamps that could offer suggestions on whether they are worth the $50+/- or should I just get a better quality old style earth clamp and clean the area where it is placed.
Cheers.

[wetduck]

I'd suggest use an angle grinder to bare crap back to bare metal to get a good earth. Also make sure earth lead is securely plugged into welder and the cable secured to clamp firmly.

[terravista]

I'd suggest use an angle grinder to bare crap back to bare metal to get a good earth. Also make sure earth lead is securely plugged into welder and the cable secured to clamp firmly.

Thanks, but I generally do that and the connection to the welder seems to be fine, but it is fixed inside the box so not visible.. The standard earth clamp only makes contact with the points of a few teeth and I assume the larger contact area from a magnetic clamp would be better,......if they work as advertised.
Cheers

[achjimmy]

The mag clamps work well. But you still need a clean earth as above and often that would entail grinding more area for the magnet . Also don’t try and weld on the back side behind the magnetic , 

Personally used to like the gclamp earths

[macca]

Yep better with the g clamp style and clean area to clamp, also important to make sure the area you are welding is good and clean. You can soon tell if the clamp is not doing its job by doing a bit of welding then grab the clamp if its hot its not right

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[austastar]

Hi,
   I was told the secret to a perfect weld, is perfect preparation.
Cheers

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[Troopy_03]

Thanks, but I generally do that and the connection to the welder seems to be fine, but it is fixed inside the box so not visible.. The standard earth clamp only makes contact with the points of a few teeth and I assume the larger contact area from a magnetic clamp would be better,......if they work as advertised.
Cheers

Sounds like the clamp is not fit for purpose. A decent earth clamp will have a copper (or brass) contact area on each face, connected by a copper braid, with the lead attached to one of the copper contacts.

[madmax2]

I have used a magnetic earth with a WIA MIG welder for many years. I have had no problems with it, and enjoy the simplicity of using it. As others have said previously, the magnet will not overcome poor preparation.

[Pete79]

In all my years in the trade I’ve only ever used magnetic earths on drums or rollers that are rotated while being welded.

Otherwise it’s just good prep that’s required.
You can cut off the crappy clamp and fit a decent one with a copper plate or connect the earth cable to a G-clamp/F-clamp, both these options work well as described before.

Though at the end of the day it can be hard to make a $100 welder work as good as a $1000 unit.

[terravista]

My welder cost way more than $100. At least 25% more. And that's probably the cause of the problems.
The earth clamp is a copper coloured pressed metal alligator grip so the earth is only utilising small points against the steel.
One new clamp coming up.
Thanks all.