Pretty much very similar to the ship in a bottle hobby. But then you look at something like this and are just like, wait did this dude seriously just unsew a pair of loafers and resew them inside the bottle? Wow.
I notice that the padlocks generally have laminated steel bodies, and are not solid brass. Presumably the procedure is to remove the rivets in the body, separate the laminations and feed each one in separately, then reassemble everything inside?
Insert a disassembled padlock (without the ear of the lock) thru the bottle neck, and reassemble it inside the bottle. Then, carefully hook the ear into the cork, and insert it into the bottle, then carefully attach the ear into one of the holes of the padlock.
Then fully insert the cork, and then use some shaking of the bottle to click the padlock into a locked position.
Remember, it doesn't have to be a padlock, it just has to look like a padlock. The internals of it could be heavily modified to facilitate its assembly inside the bottle.
> One unwritten rule with these things is that you can't "cheat". For example put an empty box of cards in the bottle and then fill it with sand. If it's a baseball, it's a baseball, not a balloon wrapped in leather.
But it doesn't have to functionally be a baseball, or a padlock. If it's a softened, ruined baseball with weak stitching that still counts. I'm pretty sure if you made a padlock with laminations held together by two halves of what would normally be a single riveted pin, that would count: or, you just make a hell of a rivet-seating machine that projects through a bottleneck, and do it for real. But the original functionality of the thing need not be preserved, necessarily. For instance, the metal might be weakened from bending and re-bending, but look normal.
I think there's retained functionality at least in the locking aspect - although, as you say, it might be weakened and not protective:
> "Find a piece of wood from the High Chaparral (Manginita wood). Drill Deck. Put case in bottle. Put cards in case. Put rope through deck. Tie knot. Put nut, bolt, and lock parts into bottle. Hold bolt with a magnet - screw nut on with dental floss. Assemble and lock padlock. Finally sign the pack of cards".
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