Ice Lock

Ice-based timed lock. Freeze the pin in the body, and at room temperature, it will take 2-3 hours for the ice to melt enough to release the pin. It's a nice alternative to cobbling together an electromechanical timed lock, and more reliable as long as you're not in a freezer :P

Printed in Hatchbox PETG at 246C, the lock will support >100lbf with fresh ice inside. PLA also works well, but ABS prints have shattered from the expanding ice. If you have that problem, check out the similar design i