I stepped on some roofing iron. easily done but the dent left was embarrassing. Such is life. The iron sheet, 6m, could be replaced or there are methods to pull the dent using unbroken rivets. I am now trying to imagine what could be done in the near future with little more power.

The pressure to dent was about 20 kg per square centimetre. The tin is screwed to the roof with the standard roofing paper underneath. This means the dent is only accessible from the facing up side with no means to get in behind the dent.

My first thought was a vacuum forming, with a pump and mold but this only gives 1kg/sqcm, not enough to pull the dent. There is magneforming using repulsion so a flux of magnetism to attract the correct shape might be a go. Although, my gut feeling is the strength of the magnetism and power needed is going to be excessive.

If one field is not strong enough to complete a task, is it possible to use other fields to supplement the state needed to carry out the task?. The added fields, in this situation, would be putting a locallised charge through the tin at the dent and also adding ultrasonic vibration.

So this future forming die would be placed against work. contacts would run an electic potiential through dent area, a vacuum pump would be applied reducing air pressure between die and metal to near zero. An ultra sonic oscillation would be sent through the work and a short sharp pulse of magnetism would be applied to pull tin into correct form.

Because all of the fields are being applied as a team group, the energy of each field is obtainable, compared to that of using just one field alone. The metal would become pliable but not melted, in an energetically malleable state. Pliable enough for the magnetism and vacuum to achieve success.

Of course, the power needed will still be quite large*.

*might be an understatement.
-- wjt, May 31 2020

hmmm, they make some very powerful suction devices for lifting tile and sheets of glass you might be able to use to undo your dent.
-- 2 fries shy of a happy meal, Jun 01 2020


The vacuum can only be at max, a 1 atmosphere difference, at sea level, from one side.
-- wjt, Jun 01 2020


Why? Is that a rule or something?
-- 2 fries shy of a happy meal, Jun 01 2020


Purge far side with inert gas, anneal with blowtorch? (Note: I have no idea if this would work.)

Or for a time-tested solution: Bondo, light sanding, and fresh paint.
-- sninctown, Jun 01 2020


[2 fries] Yes. The vacuum pump can only remove the gas molecules that make up that 1 atmosphere. That's why those lifting pads are so big, giving more grip area that the outside pressure can push on.

[sninctown] Can't get to other side. And yes, hiding the defect is a possible solution.
-- wjt, Jun 01 2020


Step all over it to make it even
-- pocmloc, Jun 01 2020


Dent removal on cars used to be done by artfully pushing it out from the back. Then someone worked out that you can weld small studs on and use a slide hammer to pull it out from the outside. The real stroke of genius came when someone realized you can do a similar thing using hot glue. Then you can leave the paint on.
-- bs0u0155, Jun 01 2020


My truck suffered a boo-boo a couple of months ago : the shops I went to wanted to pull it out, electromagnetically which I heartily agreed with... but were going to remove all the paint from the panel before doing so, then repaint it afterwards... at which point I decided the dent added character.
-- FlyingToaster, Jun 01 2020


<scales a piece of car skin and roofing iron in each hand/>

[bs0u0155] Getting to that state that is not melted but very pliable would step up humans in the advancement stakes.

[2 fries...meal] I was thinking about what you said about a strong vacuum. Extrapolating a negative vacuum, a more than vacuum vacuum, could be obtained by a massing greater and greater virtual particle separation. Separating the stuff that makes space. The machine to do this and keep the particles separated would indeed be a present day technological wonder.
-- wjt, Jun 02 2020


Nope, not as yet. The change might even just stay and become a little trickle path to give a some lucky molecules of water just that extra bit of motion* .

*relative to the roof's usual uniformity.
-- wjt, Jun 04 2020


Could you use a pulsed vacuum, if you tuned it to the resonant frequency of the plate it might have more effect.
-- pocmloc, Jun 04 2020


//The vacuum can only be at max, a 1 atmosphere difference, at sea level, from one side.//

Use 2 of them then.

(Just kidding, I like the pulsed vacuum idea).
-- AusCan531, Jun 05 2020


So the pulsed vacum just heat stresses metallic structure, making it softer slightly?. Really it just patterning the energy of the vacuum field but it may alter all the other energy patterns used.
-- wjt, Jun 05 2020


I assume there would be some other physical effects, such as plastic flow at certain ultrasound frequencies maybe. You could tune the pulsed vacuum to the other fields being applied. At the very least there would be chladni type vibrational patterns at different frequencies
-- pocmloc, Jun 05 2020



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