My folks have a mantle clock that is old – the kind with the key to wind up the spring to make it run.
One guy who fixed it years ago told him that when it isn’t running, he should store it "wound" – that is, wind it before storing it without setting the pendulum in motion so the spring stays tense during storage. He said the spring will last longer that way and that if you don’t do this, the spring will deteriorate faster.
Is this true? and… why?
when the spring is unwound it exposes more metal to the air, there for allowing more area to rust,