Silicone rubber dome switch casting mold

thingiverse

This is a reusable mold for casting silicone caulk into rubber button domes. The 4mm conductive carbon rubber discs can be obtained as a TV remote repair kit which can be very cheap and contain a few tens of these discs, but I've never seen anyone selling one-button domes for use with custom boards. A rubber dome switch has a more game controller-like feel than microswitches, as factory made game controllers frequently use these. To use the mold, rub a bit of liquid soap onto each half, put the carbon disc in the pit of the bottom half and then fill the top half's round part with silicone. Close the mold and leave for a few hours, then gently separate. There are two top halves, one producing a dome with flat top, and one producing a dome with a pitted top that can be held in place better by a plastic switch top. The top parts were redesigned to print easier but the interior is the same- print all parts with active surface facing up and using PLA, as it is smooth which makes the silicone easy to separate in one piece. The two holes serve a double purpose- they produce protrusions that facilitate attaching the dome to the printed circuit board, but also let the air out when closing the mold, so don't close them off.