How To: Spot welding

[Mike Kelly]

If you are considering buying a spot welder for your projects, this is a good read .

https://www.autospeed.com/cms/a_113277/article

https://www.autospeed.com/cms/a_113279/article

https://www.autospeed.com/cms/a_113278/article

[Jacques Reed]

Hi Mike,

Good articles. I would like to have one at times but I had a guy in Dandenong who did spot welding for me. Sadly, like so many other older businesses he has closed shop since I had the chain box lids done.

I have been amazed at some of the spot welding done on my GS body. They must have been very powerful to spot weld 1" half round bar to the 1/8" steel floor. Think I would black out the neighbourhood even if I had one like that!

Cheers,

[Mike Kelly]

Nice job on the chain box lids

Rather than using the electric spot welding process, many home hobby people use the plug welding technique where you drill a hole in one side and fill the hole using a Mig or Tig welder , you grind down the plug weld flat , it's a rather messy method but it does work. I used that method on the C8 body , where some of the panels are up to approx. 2mm thick.

These days, the home hobby welders have gone ahead in leaps and bounds: for around 600-70 bucks you can buy a decent quality all singing and dancing TIG welder and weld just about anything including Aluminium. I'm not a fan of the 3 in one welders myself, the Stick, Mig and Tig in one box style of setup, they are a compromise to some degree.

[Bruce Parker (RIP)]

Drilled 5/16" to 3/8" holes and a large number of clamps plus a grinder is my spot welder...not that I wouldn't like to do otherwise.

[Mike Kelly]

I've seen situations where certain fussy restorers do the plug weld, grind flat then use a small spot drill to replicate the small dish that a genuine spot welder leaves on the panel. It never looks totally convincing though , because the genuine spot crater has a slight dish or cratered shape to it that is not easy to replicate

The welders at the local TAFE were 3 phase things..... like night and day the difference to the average home setup struggling with single phase .. your grandmother could do perfect large welds with those industrial machines.

When I built the new Land Rover tailgate I used a common household adhesive on the Alu panels.. it's still holding up good as new years later despite being out in the weather . I visited Ian Duddy the Land Rover body builder and he showed me the method of spot welding he uses on Alu panels ... and all he had was a medium sized small factory spot welder.

[Bruce Parker (RIP)]

Originally Posted by Mike Kelly

I've seen situations where certain fussy restorers do the plug weld, then use a small spot drill to replicate the small dish that a genuine spot welder leaves on the panel. It never looks totally convincing though , because the genuine spot crater has a slight dish or cratered shape to it that is not easy to replicate

The welders at the local TAFE were 3 phase things..like night and day the difference to the average home setup struggling with single phase .. your grandmother could do perfect large welds with those industrial machines.

Ah, and then there's the reach. I'd spend the bucks to get a home spot welder only to find the welds I need are beyond the reach of my new toy. If the right dimple was a thing I'd get out the dremel tool.