Welding Tips and Tricks

I have two old project trucks which have some rust issues that will require some sheet metal cut and weld patching. Looking for recommendations for grounding. These projects are actually the reason I started taking a welding class and bought a welder.

I've seen the suggestion of welding a tab to the body panel for the ground clamp, although I am unclear how one welds a tab onto a panel for the ground clamp, before one has the tab for the ground clamp... seems like chicken and egg issue.


Second I've seen magnetic ground clamps, this seems like it would be the preferred method. Maybe more expensive than a tab of scrap steel, but could be easily moved to be close to the work, and nothing to grind off when done.

Open to other ideas.


Also I assume it is a good idea to disconnect the battery of the vehicle? 1958 Dodge and 1969 Toyota Landcruiser so no computers or other sensitive electronics to worry about.


I tried searching the projects to see if someone had a project vehicle, but nothing appropriate came up. If anybody knows of a post here, a youtube link etc of somebody doing sheet metal repairs on a vehicle with a welder, please feel free to link to it.

Thanks

Grind/sand off a spot on the body where you can put your ground(work) clamp, and clean a spot where you can weld the tab, or just clean up different places on the body for the clamp

I threw away my spring ground clamps long ago and only use the Magswitch grounds on everything. Make a handle from a piece of 1/8X 1"X5" flat bolted to the lug and 2nd bolt for the ground cable end and tape it up. Just grab the handle to flip it anywhere. The ones with cooling fins have a one piece body (300+ amp) where the older style smooth ones have a two piece body and can corrode in the seam, short a bit and get hot. For non-ferris material just clamp on a piece of flat steel and stick it on.

i have heard of using several mag clamps with the earth wire running between them. that way you can spread the earth connection along the length of the weld. i've heard that it can help with welding thin sheet metal.
i would be interested to hear if thats actually true or a myth.

tweake wrote:i have heard of using several mag clamps with the earth wire running between them. that way you can spread the earth connection along the length of the weld. i've heard that it can help with welding thin sheet metal.
i would be interested to hear if thats actually true or a myth.

I find the presence of magnets when welding thin sheet metal to be the Devil's Own Curse. The field disrupts the arc, particularly badly with TIG. I guess with the Mag Switches, you could locate the magnet far enough away on the panel...

Tacking a piece of steel to the panel (a section of steel tube, a clipped corner, etc) to the body panel in a clean area is best in my experience. The part you're repairing is usually rusty anyway, so finding a quality connection that is not pathed through rusted components is very tricky. For good arc control, you need a clean, good, ground. Its hard to get a clamp-type ground to bite a panel unless you bite from the edge, and then you're dealing with rusty undersides. Tacking to, is the approach I prefer...

Thank you

I can see where both could be handy, the magnetic where there is just one spot to fix would be quick and easy, while on a panel with multiple spots to fix the added work of welding and removing a tab is minor compared to the work being done.

Those Magswitch clamps look pretty reasonably priced, so easy to get one to try out and see how I like it.

Clamp the tab in the ground hold and weld fast magnets and DC welding don't go together and I seriously doubt either of those vehicles have computers in them don't forget all the panels on the top side should go behind the lowers or you can create a pocket to collect moisture where you cannot seal it off

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cj737 wrote:

tweake wrote:i have heard of using several mag clamps with the earth wire running between them. that way you can spread the earth connection along the length of the weld. i've heard that it can help with welding thin sheet metal.
i would be interested to hear if thats actually true or a myth.

I find the presence of magnets when welding thin sheet metal to be the Devil's Own Curse. The field disrupts the arc, particularly badly with TIG. I guess with the Mag Switches, you could locate the magnet far enough away on the panel...

magnet issues aside, is the approach of having multiple earth points all connected at once beneficial at all?

i think the idea was that thin sheet can have issues because current is trying to flow through thin sheet directly from arc to earth clamp resulting in the weld being hotter on that side of the weld. with multiple earth points the current flow has different directions to go and spreads it out a bit.
thoughts?

Whenever I've seen my brother doing any kinda body welding on vehicles he's always just cleaned a small spot on the pinch weld of the rockers and clamped there.

Whether it's the best choice I'm not sure but he has always had good results with that method.

As far as battery protection goes we actually have this little surge protector device that just clamps on to the batter terminals like you were jump starting he car. Very handy if your in a time crunch or simply don't want to deal with undoing terminals etc. I can post a pic of it tomorrow when I'm back in the shop if your interested.

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