"Paintless" Dent Repair - FAIL, for now

[RichardL]

Wanting the remove some small dents, and one large and ugly dent,  from my barn-find A7 tank, I bought a cheap kit that adheres the puller pucks with hot glue. Hahahaha x 10e23. "OK, that's it. This is war!" Welded a fat nail to the dent and rigged up a means to hold it in my vise and pull it with a lot of force. The bending planks in the pictures are oak. Started with the jack near the plank ends, then moved it closer to the action for more force and less bend, Not a trace of movement. Almost broke my vise support platform from the bench. Can't believe how strong the weld is with my crude spatter skills. My next attempt will be to thread the nail and fashion a slide hammer.

Richard L.

(Photo change coming in a minute.)

[RichardL]

My, what a messy shop you have, Richard L.

Haven't recovered yet from the brake and fork-leg rebuild.

Richard L.

[muskrat]

G'day Richard.
Try bolting the tank to the bench and heat the dent while pulling on the nail. Try clamping a slide hammer to it.
Oak  you need some good old Aussie hard wood. Iron Bark hardness 14, American Oak hardness 6.
Cheers

[Greybeard]

Have you not had your spinach today Rich?

[berger]

musky or borrow my lignum vitae , can't knock nails in that even pre war good old steel nails , it also blunts drills made in china , well i am not surprised on that score 

[muskrat]

G'day bergs.
OK you win! I had to look up lignum vitae, never heard of it. It's 19.
Cheers

[berger]

musky it is used as bearing material and was used to prop ships up in dry dock, no good in water though it is that dense it sinks faster than a brick

[BSA_54A10]

Wash & dry the tank bu running your car exhaust through it till it it too hot to touch
Replace both of the fuel taps with 1/2 BSPP plugsand run a strap between them to prevent the tank spreading
If the tank has a front strap put that on as well .
Fill the tank to the very top with chilled water ( no ice )
cover the fuel neck with several layers of glad wrap ( pallet wrap is better if you can get some )
Turn the tank so that the dent is at the absolute top
With an oxy torch heat arounf the edge of the dent , about 1/4" to 1/2" into the dent .
As thewaret heats up & expands it will push on the inside of th dent & as you heat the metal it will yield to the pressure .
This is a very long & slow process but works very well

All of the Painless / weld & pull stuff is designed for use on moder cars with toilet paper thin metal pressings .
IF you can clamp the tank down tight & apply some good force on the welded on bolt then you can use the same heat technique but make very sure there is no petrol residues left in the tank or it is bang time
I have seen the same thing doone heating the circumference with an induction loop at a demo one time but it did not make me drag 2 grand out of the wallet .

You can also heat shrink it out , but that requires quite a bit of skills if you don't want it to enf up looking like a bas case of the mumps .
When using the heat shrinking technique you heat the actual bend itsel red hol, hold that hear for a few minutes then chill the surface with a damp rag ( not direct water spray ) This works because the inside is still expanding when the outside cools and contracts so it is a case of torch in one hand & rag in the other

[Greybeard]

lignum vitae was used on my Austin Seven for the shock absorber friction disks; very similar design as the BSA steering damper. Makes me wonder if BSA used LV for that job.

[RichardL]

Slide hammer setup and some work-in-progress pics. I think I'm gaining on it, based on the sharp edge in the before pic. Against some folks' better judgement, I'm using wide-flame oxy-acetylene.

Richard L.

[Greybeard]

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[RDfella]

When faced with dents like that I usually cut an access in the bottom to enable panel beating, then weld back the removed part.
 

[Swarfcut]

 Thinks.....At times like this a custom tank cover seems a most attractive alternative. Well done for trying, but with oxy to hand, brazing on several pull plates is another option..... Removal of a brazed joint being less aggressive to the parent metal than something welded on. If all else fails, as the maestro intimates, cut a hole in the bottom and simply knock it out. Slide hammer at a single point will result in a peak, a single point pull is unlikely to pull out the whole dent in one go.

 Swarfy.

[RichardL]

I'm up to three nails and plan to add as many as it takes to pull the thing out to a point where the bondo is reasonable. No chrome intended. I don't have TIG and really don't trust my skills enough to replace a large panel intended to be leak free. If the spatter welds cause pin holes, I think I'm OK filling those with weld or braze.

Richard L.

[berger]

Richard have you thought about a tin of car body filler, or are you relishing in the challenge