Magnetic Ground Clamp

bigtiller · May 3, 2017

How do they work? Does it need clean metal or does it work through paint ot a little rust?

Airgas - RAD642118 - Radnor(R) Model MGC-3 3 Amp Magnetic Ground Clamp

Eric Salop · May 3, 2017

With a magnetic clamp you still need to make a good low resistance electrical contact with the metal below, so paint or thick rust would need to be removed first. You may get away with using it over light rust, though I would take the extra few seconds to clean the surface with a wire brush and be sure.

The one I use has a little lever that can be turned to reduce the magnetic force to almost zero. That makes it easier to remove. It also greatly simplifies the task of cleaning accumulated magnetic "filings" that inevitably accumulate when grinding. They cost a little more, but I think they are worth the extra money.

Big Barn · May 3, 2017

I like mine. Nice for those projects that don't have an area close to your weld where a traditional jaw clamp will work.

Terry

IslandTractor · May 3, 2017

Needs clean metal for the electric contact. Magnet works over rust or paint. Electric contact usually right in the middle of the magnet like a bullseye.

bigtiller · May 3, 2017

Ah-shucks, I was hoping for a shortcut for one less spot to clean up and repaint.

yomax4 · May 3, 2017

I would suggest one like Big Barn shows. Great for larger pipe and hard to reach places. I used to sell these things and the bigger the better and you get what you pay for although most of these are over priced. You will still need a regular ground for non ferrous of course.

Big Barn · May 3, 2017

yomax4 said:
I would suggest one like Big Barn shows. Great for larger pipe and hard to reach places. I used to sell these things and the bigger the better and you get what you pay for although most of these are over priced. You will still need a regular ground for non ferrous of course.

I've had mine three or four years now. My LWS(s) didn't even have them on the shelf. They wanted to order one in for me.

I "ordered " it myself from Amazon. Cheaper too.

FarmWrench · May 3, 2017

I've got a cheap one. Fills up with grinding dust quickly. Not strong enough for rusty/painted. Copper lined the jaws of some clamps and ran cable to it for my little mig. Nice to be able to hold little stuff well with just the ground clamp.

dragoneggs · May 3, 2017

Big Barn said:
I've had mine three or four years now. My LWS(s) didn't even have them on the shelf. They wanted to order one in for me.

I "ordered " it myself from Amazon. Cheaper too.

Amazon link?

Big Barn · May 3, 2017

dragoneggs said:
Amazon link?

Here's an Amazon link but better shop around. I'm certain I paid less, but several years ago.

Magswitch Ground Clamp 3AMP Magswitch 3 amp On/Off Magnetic Ground - Welding Clamps - Amazon.com

dragoneggs · May 4, 2017

Big Barn said:
Here's an Amazon link but better shop around. I'm certain I paid less, but several years ago.

Magswitch Ground Clamp 3AMP Magswitch 3 amp On/Off Magnetic Ground - Welding Clamps - Amazon.com

Thanks Terry... although a cool toy, I am not sure I can justify it but it WILL go on my xmas list.

I can see for certain situations (heavy equipment) finding something nearby to clamp to might be an issue. I'm a hack and probably shouldn't be in those situations anyways :laughing:

Big Barn · May 4, 2017

dragoneggs said:
Thanks Terry... although a cool toy, I am not sure I can justify it but it WILL go on my xmas list. I can see for certain situations (heavy equipment) finding something nearby to clamp to might be an issue. I'm a hack and probably shouldn't be in those situations anyways :laughing:

One can certainly get by forever without one but....

Quite often I need to tack up an "assembly" that can't be held tightly in place with clamps. Just carefully attaching the jaws of a traditional ground clamp may knock everything out of position.

The Magswitch however can usually be attached without disruption.

Plus as yomax4 mentioned, it's great for large pipe, large flat surfaces AND my 3" thick steel welding table top.

Terry

dragoneggs · May 4, 2017

Definitely see applications. Surprised after going through some of the reviews... seems the magnet isn't all that strong. Which can be a good thing from my understanding (not personal experience) of welding near magnetic fields.

BukitCase · May 4, 2017

Mark, here's a little better price (looks like they may have changed the design, left out the smooth outer cover tho)
Magswitch Magnetic Ground Clamp - 300 amp 8100746

I've found that any grinding dust/filings come off just about ANY magnet by blowing it off with high pressure air; a quick back and forth movement seems to work best. The air gets the "stickies" far enough away from the magnet (even a NON-switchable one) not to return... Steve

Just be SURE to have leather gloves on, and not too close to skin - AIR EMBOLISMS CAN BE FATAL...

IslandTractor · May 4, 2017

I have one that looks like this: Airgas - RAD642118 - Radnor(R) Model MGC-3 3 Amp Magnetic Ground Clamp

$17 isn't bad.

The contact bolt is spring loaded so the magnet holds to the base and the spring forces the contact down onto clean metal.

dragoneggs · May 4, 2017

IslandTractor said:
I have one that looks like this: Airgas - RAD642118 - Radnor(R) Model MGC-3 3 Amp Magnetic Ground Clamp

$17 isn't bad.

The contact bolt is spring loaded so the magnet holds to the base and the spring forces the contact down onto clean metal.

I like the looks and price of that one.

Big Barn · May 4, 2017

dragoneggs said:
Definitely see applications. Surprised after going through some of the reviews... seems the magnet isn't all that strong. Which can be a good thing from my understanding (not personal experience) of welding near magnetic fields.

I just checked out those reviews, Mark and found the one regarding the weight of the cable pulling the magnet off the workpiece questionable.

I just bundled up 20 pounds of welding lead to see how it would fare.
Magnet held the weight without problem and I didn't see the point in ADDING more weight to see when it would fail.

Even if one was up a fifty foot pole I'm certain they could loop the lead over something to alleviate the weight/strain on the Magswitch ground.

* I realize this may have been more appropriately posted in the "Get a Life" forum.

Terry

Big Barn · May 4, 2017

IslandTractor said:
I have one that looks like this: Airgas - RAD642118 - Radnor(R) Model MGC-3 3 Amp Magnetic Ground Clamp

$17 isn't bad.

The contact bolt is spring loaded so the magnet holds to the base and the spring forces the contact down onto clean metal.

Nice price but once you see the advantage of a "switchable" magnet not "pulling " apart a delicate assembly when attaching you'll never go back.

LittleBill21 · May 4, 2017

BukitCase said:
Mark, here's a little better price (looks like they may have changed the design, left out the smooth outer cover tho)
Magswitch Magnetic Ground Clamp - 300 amp 8100746

I've found that any grinding dust/filings come off just about ANY magnet by blowing it off with high pressure air; a quick back and forth movement seems to work best. The air gets the "stickies" far enough away from the magnet (even a NON-switchable one) not to return... Steve

Just be SURE to have leather gloves on, and not too close to skin - AIR EMBOLISMS CAN BE FATAL...

just ordered this ty, looks to be awesome for pipe.....

IslandTractor · May 4, 2017

Big Barn said:
Nice price but once you see the advantage of a "switchable" magnet not "pulling " apart a delicate assembly when attaching you'll never go back.

Oh I can see the advantage of a switchable magnet for small things alright. But if you are welding on a big slab of metal the Radnor type does just fine. It is a two handed job to get off sometimes so there is no question that it will hold quite a bit of weight if the ground cable is suspended from the magnet clamp.