I’ve been messing with these small and inexpensive capacitive touch boards. Pro: small. Con: small.
I wanted a bigger touch surface, which could also act as enclosure. Ran across these “bath bomb” molds. They come in various sizes and are aluminum.
As is my way, I added another LED (though, it barely shows at the bottom) and haptic feedback (phone/pager motor).
Going to use the same design with a Kenwood style headset plug, so it can be used to trigger FRS & Ham radios. A big Push To Talk.
No need to solder to the aluminum (it will just suck up heat). I use a strip of copper foil tape between the board and the “bell”. I use this tape when I encounter odd wiring situations. Very handy.