Spot Welding with MIG

Never to be one to shy away from picking up a new tool, I was investigating picking up a Harbor Freight or similar spot welder. As with most everyone here who’ve done a restoration, I’ve got some sheet metal work to do on the Jag. Not a lot of it but enough to justify something to make life easier.

I came across a welding forum where someone has the same welder that I have (Esab Rebel 215ic) and was asking about the spot settings. Unbeknownst to me, the Esab as well as most other big name TIG welders will run in spot mode.

Eastwood actually makes special spot welder tips and vise grip pliers as demonstrated here on their YouTube channel.

These shields are pretty common. Tweco has 21-62-fas and Lincoln has something similar. I can always resort back to plug welds but if I can get by with these, then I’ll go that route.

Are you using your welder in Mig mode, or Tig (as suggested by your thread title)?

Fixed it.
Although there are also videos of using Tig too. My Tig uses lift start so it isn’t optimal.

I have a decent amount of welding experience( I went to a Welding and Fab school) and I have spot welded with a MIG before and if you have your settings right and gas flow just right you can get a near perfect spot weld but it will take some practice. Also, you don’t need that kit but it would be good to learn on.

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That looks kind of neat. Makes me want to start another restoration project but I am afraid that instead of me moving to an assisted living facility my family would see to it that the tools and keys were locked away.
It gives you another option and it probably isn’t very expensive. Would save drilling or punching a bunch of holes.

Regards, Joel.

Right, but the trade-off is that you need a lot of heat in one spot compared to plug welds. That could lead to warping in some cases. Also, the resulting “spot” of the weld is huge (see video). The device just holds the wire feed a fixed distance from the metal–you can do the same with your standard tip. I tried it when the Eastwood product came out several years ago…seemed to me that you needed too much heat in one place.

I have a conventional Lincoln spot welder, which works great except it’s useless for portable use because it weighs a ton. The weld is about 1/8 inch in diameter–similar to the original welds.

Nerdy fun fact: Stainless is the most miserable metal to drill and machine, but it is the easiest to spot (resistance) weld. The nickel and chrome have high thermal (and electrical) resistance compared to steel (and especially, aluminum). So with resistance welding, stainless steel’s electrical resistance dissipates lots of power. That power creates lots of heat. Then, the high thermal resistance allows the heated spot to retain its heat and melt, rather than having the heat rapidly conducted into the surrounding metal. In contrast, aluminum (low electrical and thermal resistance) is very difficult to spot weld, and requires very expensive equipment to do so.

BTW, the same physical property of a metal determines both its thermal and electrical resistances–so they always track with each other.

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I’ve got plenty of floor metal from the car and new sheet to work on getting the settings set correctly. I also didn’t like the size of the weld with the Eastwood products. Luckily most of the welds that I will be doing are interior to the car so a little excess metal on the surface will be acceptable and covered by carpet and such.

I already have an air flange/punch tool which makes plug welding go faster, I’m just looking at options and alternatives. I’ve also got a number of cheaper vice grip pliers around that I will modify to act similar to what Eastwood shows. I might solder a copper disk on the back side to act as a heat sink in case I do go the plug weld route.

Many options available. Just need to ensure good solid welds.

Understatement of the day. :wink: I also build suppressors and in the online community, stainless is discussed regularly for the difficulties in it work hardening. The couplers on me and my wife’s tandem bike are stainless and we have to use a special, i.e. expensive, grease to ensure that the threads don’t get galled up.

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Nine months ago, while he was visiting from Switzerland, Andrew Waugh and I got into a conversation about spot welding aluminum. I had seen somewhere online a purpose made aluminum spot welder that sandwiches the two aluminum sheets to be joined between two strips of steel. The steel strips reportedly provide the resistance required to focus sufficient heat to fuse the aluminum. I have a 220v Miller spot welder so we headed off to the shop, each with his large glass of wine in hand, to test it out on some 18 ga aluminum I bought for TIG practice. Worked. So, you don’t need expensive equipment after all to spot weld aluminum, though manipulating the steel sandwich while clamping on the welder tongs can be awkward.

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I was skeptical, thinking that the veritas of your observation might have derived from the vino.

But I googled…hard to find, but yes! Extremely cool! I will try it. This commercial method (below) uses very thin steel…did you and Andrew, or was it thicker?

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Well, I’ll be dingle-dangled: my ‘new thang’ for today!

As I recall through the merlot-induced fog we used whatever sheet steel there was on hand, so likely 20 ga.

If you search youtube for “ metal shaping with Lazze spot welding aluminum” there is a demonstration of the technique.