But it was a night of letting off fireworks in a Hamilton North park and then blowing up the mailbox of a man who called police that has landed Daniel Fing back behind bars.

Fing, now 35, was letting off fireworks in Smith Park about 9pm on October 13 last year when a man in nearby Boreas Road called the police.

About 4.50am on October 15, Fing and his girlfriend returned to the park and Fing told her: "I'm going to get this c---sucker".

He then put an explosive device in the man's mailbox and lit it, causing a huge explosion that woke people up two blocks away and sent pieces of the mailbox flying all over the street.

Crime scene officers examined the scene and the man who had called the police about Fing provided them with a picture of the car that had been parked outside his house two nights earlier.

Police traced that car back to Fing and then raided the family home at Belmont North, another home at North Lambton and two storage sheds at Belmont, uncovering a significant stockpile of weapons, guns, detonators, slingshots, arrows, blow darts, ammunition and chemicals.

Perhaps most troubling, given Fing's history, was what police found open on his computer - PDF documents that included "DIY gunpowder cookbook", "How Napalm is made", "The Chemistry of Powder and Explosives" and "US Army Explosives and Demolitions Manual".

Fing, who is represented by solicitor Kristy Winter, appeared in Newcastle Local Court on Wednesday and pleaded guilty to blowing up the mailbox and a string of firearm and weapon offences.

He will next appear in Newcastle District Court next month to get a sentence date.

Fing was extradited to Queensland in 2016 to face charges relating to the discovery of 50 kilograms of explosive materials at a Brisbane "bomb house" in 2014.