Half a croissant, on a plate, with a sign in front of it saying '50c'
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Nail-Removing Gun

Involving explosive compression of a magnetic field
  [vote for,

It is well known that an electromagnet can generate a fairly strong magnetic field. Less widely known, however, is that it is possible to greatly intensify a magnetic field, at least temporarily, by using an explosion to compress it. See link.

And, there is a completely different way to temporarily generate a very strong magnetic field, which I've mentioned in other Ideas here involving nuclear fusion. See "theta pinch" link. What if the two extremification methods were combined?

So, this Idea seems like a fitting "complement" to the ordinary nail gun, that uses an explosion to drive a nail. It should be possible to use an explosion to PULL a nail, at least as long as the nail is made of something magnetic like steel.

In more detail, I'm going to start with a gun-body that contains a bank of capacitors, and which plugs into a wall outlet. Appropriate electronics charges up the capacitors. At the end of the gun-barrel is a sacrificial theta-pinch coil; we will of course place the end of the barrel against the surface holding the nail that we want to pull. It is to be noted that this particular gun barrel needs to be rather thick, to withstand the forces about to be described. It should also be made of something non-magnetic, perhaps titanium.

When you pull the trigger, two things happen in very quick succession. First, the capacitors are discharged through the theta-pinch coil, generating a very strong magnetic field.

Second, and just as the magnetic field in the theta-pinch coil is reaching maximum strength, we apply several small ordinary explosive charges around the theta-pinch coil. This will physically crush both the coil AND the magnetic field it has generated, causing its intensity to go up even more.

The enormous magnetic force now pulls out the nail! The nail flies into the gun barrel and certainly will hit the collapsed theta pinch coil (doesn't matter since both nail and coil are to be trashed/recycled). The gun barrel does NOT need to be open at the other end, which of course ensures that the nail's motion is safely stopped.

Vernon, Aug 17 2011

Explosions and magnetic fields http://www.nap.edu/...d_id=11211&page=116
As mentioned in the main text. [Vernon, Aug 17 2011]

Theta Pinch http://www.physicsf...thread.php?t=331939
As mentioned in the main text. [Vernon, Aug 17 2011]


       Explosive, expensive and more easily accomplished some other way. I like it.
baconbrain, Aug 17 2011

       Cat troubles again, eh?
Alterother, Aug 18 2011

       Now that you mention it, the wording does have a bit of a Borgy quality, doesn't it?
Alterother, Aug 18 2011

       How big a magnetic field would it create, and would that be enough to pull the nail?   

       My version of a quick nail puller would be a solenoid that somehow attaches to the nail head (maybe a small self-tapping screwing protrusion).
xaviergisz, Aug 18 2011

       A quick resistance weld with a break-off mechanism would work much better.
Alterother, Aug 18 2011

       //        How big a magnetic field would it create, and would that be enough to pull the nail?    //   

       I have know idea how much magnetic force the base of a magnadrill puts out, but it's enough for a grown man to hang from if you stick it onto a steel column or something. Just for grins I went downstairs and tried to pull some nails out of a studwall with mine-- no dice.
Alterother, Aug 18 2011

       Folks, I figure that even if this gadget doesn't pull the nail entirely out, it ought to pull it out enough so that some other tool (like a hammer's claw, or perhaps diagonal cutters) can grip it directly/physically, letting you pull it out the rest of the way.
Vernon, Aug 18 2011

       Either that or it will backfire and punch the nail out the far side the wood. A success either way!
Alterother, Aug 18 2011

       I imagine this is possible and not viable due to the obvious implications of having a succession of nails, as a nail is rarely found alone. The quick acting nature of the device actually makes it more dangerous since the other metal it would attract would ricochet, rather then stick.   

       also its baked   

       wikipedia: "Non-nuclear electromagnetic pulse" "There are a number of devices that can achieve this objective, ranging from a large low-inductance capacitor bank discharged into a single-loop antenna or a microwave generator to an explosively pumped flux compression generator."   

       Although it would be a great gun in case the machines take over.
nickthird, Aug 18 2011

       You would need a device the size of a small planet to remove a nail put in place by a nail-gun (in my experience)
xenzag, Aug 18 2011

       So, this is not some Chinese torture device for removing one's fingernails...?
xandram, Aug 18 2011

       "explosive compression"   


       For an encore, you could use it for MRI scanning of small objects ...
8th of 7, Aug 18 2011

       With that many capacitors wouldn't it be easier to just vaporize the nail? or make your own tack-weld puller?   

       What am I saying.
Ignore that.

       Can somebody please try this? Sounds like an outstanding DIY project for someone with more money and access to explosives than me. Maybe we should send it in to the Mythbusters.
DIYMatt, Aug 18 2011


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