My first iteration of a timed lock by an ice cube. The lock contains 3 parts and takes a regular ice cube. There is no need to put the lock in the freezer and worry about the parts breaking because of the expanding ice.

Maximum size of the ice cube this lock can take 30x30x30mm. It takes about 2 hours at 22°C for the lock to release.

To use it, put the two bodies together and place an ice cube inside. Place the lid onto the top and wait for the ice to melt. The lid snaps into the body with a snap fit and is slightly recessed so it's impossible to remove without tools. When the ice has melted and the 'key' part is removed, the lid falls out because it is held in place by the key part.