Tran Duc Thuc and Tran Duc Son are now in custody as police investigate their firecracker business.
Thuc was on his way to deliver around a dozen firecrackers weighing around one kilogram each to a customer when he was stopped by police on Monday night.
Upon investigation, officers found 25 more firecrackers weighing a combined 50 kilograms along with production materials and tools at his home.
Thuc admitted he had bought the materials and taught himself to make firecrackers for sale.
Having finished producing the first 25 firecrackers, he had found a customer willing to pay him VND200,000 ($8) a piece.
Based on Thuc's testimony, police checked the residence of Son on Tuesday and found him hiding 71 firecrackers in the kitchen. They also seized 59 kilograms of explosives.
Son told police he was in need of money and had decided early this month to make and sell the firecrackers.
Thuc and Son are students at a vocational school in Nghe An.
Vietnam banned the production, trade and use of firecrackers from 1995.
Those who produce and trade firecrackers with a volume from six to 40 kilograms will be fined from VND100 million to VND1 billion or jailed from one to 15 years.