Spot Dent Puller....blew a hole!

[Myles1970]

I've been given a spot weld dent puller on loan to do a few little jobs on my car resto. Control-wise it has an on/off switch and a dial (a timer). It's the type with an earth lead and a slide hammer on the positive side with the three pointed star on the end. Can't remember the make at the moment, but it has proven quite handy with pulling a dent on the sill, where I had 'peeled' it open and it had work-hardened when I bent it back. I was using it to do some shrinking on the rear lamp panel with some success, when, after sharpening the business end (on the advise of the lad who lent me it), with a shower of sparks it blew a hole in the panel . I wonder if it was too sharp? Fixed amount of current through a smaller area?

 

[Myles1970]

…. Just one of those things I suppose

 

[Dcal]

Was it a thin spot from rust or grinding?
Have you a photo of the tool?

Always thought they would be handy, instead of mig welding washers onto a 3/8 bolt for my slide hammer, but I probably wouldn't use one enough to be worth while.
Certainly a lot better than using a big coarse self tapper like our American cousins do.

 

[chris y]

I havent used a spotweld puller, but have quite a bit of resistance welding.
I think you will be correct, current density is the term, youve got the same amount of voltage, trying to pass the same current, through a small area. Just flatten it slightly, and make sure you dont have too little force applied during the weld.
Impressive work!

 

[Myles1970]

Was it a thin spot from rust or grinding?
Have you a photo of the tool?

There’s actually no label on it…. Very useful if you’re interested in doing regular restoration work, and I’m sure one could become quite proficient with it, but if I can reduce the amount of filler required I’m happy. Also managed some shrinking with a map torch, but that was scary…

@chris y thanks Chris, the proof will be in the paint though

 

[500e]

Never tried a map torch always OA, quicker heat in the spot
Teckna used to be the one to go for I note Vivor has them at less than £200

 

[maroon]

View attachment 366013

…. Just one of those things I suppose

jesus christ.... could you not get a dolly around the back?

 

[Myles1970]

jesus christ.... could you not get a dolly around the back?

What for?

 

[maroon]

What for?

hammer it into shape.

 

[Myles1970]

hammer it into shape.

Access is quite restricted, I could barely get my hand in never mind a dolly…, never mind swinging the dolly. I’m sure an experienced panel beater would have done a better job, but I’m happy with it

 

[Myles1970]

Never tried a map torch always OA, quicker heat in the spot

The map gas was actually quite quick and heated it to a cherry red about the size of a 10p (old type)… hardly worth it for me to get a OA setup and the landlord wouldn’t be too happy about it (my dad)

 

[maroon]

Access is quite restricted, I could barely get my hand in never mind a dolly…, never mind swinging the dolly. I’m sure an experienced panel beater would have done a better job, but I’m happy with it

they can be quite restrictive in the corners in some cars. a lot easier replacing the panel in most instances. if you can get them.

 

[Myles1970]

they can be quite restrictive in the corners in some cars. a lot easier replacing the panel in most instances. if you can get them.

It was a good panel before I cut the arch off and tubbed it (I’m going wide-arch). The opposite quarter was way worse so I replaced it with a used one from a 3 door. 2 door quarters can’t be got and new 3 door ones are about €600 each.