According to a report, the babysitter told him he had to leave because she did not know him. She said that was when Welling grabbed boiling water from the stove and threw it on the baby.
The babysitter said she grabbed the child and ran to her friend's home for help. She said Welling ran to his truck and drove off.
The report also stated that the babysitter was able to take Welling's license plate number from his truck, before she and her friend drove the baby to the hospital.
Officers said they tracked down Welling at his home and he told them he didn't think the incident was a big deal.
According to the report, when the officers told Welling that the baby was at the hospital being treated for burns to his face, chest and groin area, Welling's response was, "Life sucks."
Investigators said they arrested Welling, who smelled of alcohol.
Welling is being held at the Marion County Jail on $5,000 bail.