Aaron Church, 33, was drug-affected when he set up two homemade improvised explosive devices on a fence near a neighbour's in Geelong in the early hours of September 27, 2020.

Residents nearby were asked to evacuate and others were advised to stay indoors.

The first device, made from a paint can containing about half a kilogram of shrapnel including nails, screws, bolds and fishing sinkers, caused a loud explosion.

Police and firefighters attended and extinguished both devices, with Church approaching police and telling them there were two more devices in a tree.

He was arrested and the other devices, made from aerosol canisters and brass pipe, were safely detonated by the bomb squad.

"I didn't really, like, set out to blow s*** up," he told police after his arrest.

"I was just sitting there bored and just kind of made it, and it was there."

Police searched his property and found more bombs, material including sparklers and nails, and a sling-shot weapon.

Church pleaded guilty to unlawfully and maliciously causing an explosion, making an explosive substance and possessing a prohibited weapon.

Judge Justin Hannebery said while the explosions only damaged a fence, there was a risk that the bombs could have endangered life and property.

"Your actions were staggeringly immature but ultimately benign," he told the County Court on Tuesday.

"I do not accept this was just relief from boredom, but there is no evidence any more sinister motive was inferred or that he wanted to damage his neighbours."

He said the bombs were unsophisticated and the materials could be easily obtained from most supermarkets and hardware stores.

He said Church, who has been on remand since his 2020 arrest, had shown remorse for his actions.

Judge Hannebery sentenced Church to two years and three months in prison and fined him $500.

He is already eligible for parole, having spent 639 days in custody.

Australian Associated Press