Imagine a shoebox with 1/2" thick walls and only about an inch deep.  On the "top" of the wall s of the box, there is a small half-round bead sticking up right in the middle of the thickness of the wall (round side up).  Now take the lid of your shoebox (also 1/2" thick) and look on the bottom side, and there is a half-round groove all around the perimeter of the lid.  Cut a "window" into the center of your shoebox, and make provision for introducing pressure.  You put a foil sample on the open top of the box, and drop the lid over it.  The half-round, when clamped, prevents the foil from just pulling out from under the lid, which is clamped to the base good and tight.  The foil gets pressure behind it and pops up through the window until it breaks.

Easy peasy, except for a bunch of hours in the machine shop.