Activate Cauldron of Souls by tapping it, giving Gerrard persist until end of turn.
Activate Extruder by sacrificing Cauldron of Souls, putting a +1/+1 counter on Gerrard.
Activate Blasting Station by tapping it and sacrificing Gerrard.
When Gerrard dies, it and its persist ability trigger.
Resolve the Gerrard persist trigger, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When Gerrard enters the battlefield, Blasting Station triggers, untapping Blasting Station.
Resolve the second Gerrard trigger, failing to exile it as it has left your graveyard, and returning Cauldron of Souls from your graveyard to the battlefield.
Resolve the Blasting Station ability from step 3, dealing 1 damage to any target.