How can I hide the volume slider?

I am in the process of making a new glassy, minimal style skin and I want to hide the volume slider until the volume icon is clicked.
Here is what I would like to have it do (if I can):
the controls are all on a glassy "clip" attached to a glassy base to display the album art, time and track info. the clip has two rows of controls - the player buttons and below them, the icons for operations such as shuffle, repeat, playlist and volume.
I would like to have the volume slider, track and bit hidden in the space between these two rows, until the volume icon is clicked and then have it hidden again when the icon is clicked again.
I know I can do this for pop out panels using the id(panel), but does this use the action_layer_switch? and how would it be implemented?
Here is what I would like to have it do (if I can):
the controls are all on a glassy "clip" attached to a glassy base to display the album art, time and track info. the clip has two rows of controls - the player buttons and below them, the icons for operations such as shuffle, repeat, playlist and volume.
I would like to have the volume slider, track and bit hidden in the space between these two rows, until the volume icon is clicked and then have it hidden again when the icon is clicked again.
I know I can do this for pop out panels using the id(panel), but does this use the action_layer_switch? and how would it be implemented?