10-year-old's after-school side hustle generates thousands of dollars: How he manages his 8 p.m. bedtime.

Every morning, Jacob Heitmann checks his 3D-printing business for orders after eating breakfast and using the computer in his family's basement.

Heitmann heads to his fourth-grade classes while his 3D printer creates a rainbow plastic skeleton, which is his favorite design. Most prints take at least two hours to create.

Heitmann has generated over $1,700 in revenue from selling 3D printed toys to classmates, on his website, and through his Etsy shop since January. Most of his toys cost less than $20 each. He spends about three hours a day working on his side hustle, according to CNBC Make It's review of documents.

"Heitmann has always wanted to sell things to people, stating that it's enjoyable to set up a listing and determine the price. He feels like a big businessman when he does it."

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Heitmann convinced his parents to purchase a $300 "Ender" 3D printer from Creality for his birthday last July, despite the machine's ability to only print one color at a time. "I told them it was cutting-edge technology that was revolutionizing the world," Heitmann recalls, chuckling.

Heitmann, armed with his printer, spent his time watching YouTube videos, taking classes on Outschool.com, and requested a second device, a Bambu Lab P1S multi-color printer, which costs $949.

Santa delivered it for Christmas, Heitmann's father Chris says.

An entrepreneur by nature and nurture

At a young age, Heitmann began his entrepreneurial journey by requesting assistance from his grandfather, who owned a printing promotion company, to produce branded T-shirts and sweatshirts for his YouTube account, which he started under his father's name to share his passion for Roblox and Minecraft.

He launched an Etsy shop under his mom's name in February, but didn't put enough effort into selling apparel, resulting in selling only 20 units before replacing the listings with his 3D-printing designs. Heitmann says that he and his friends, some of whom also have their own 3D printers, were asked by teachers to stop soliciting sales in class.

In April, a family friend requested Heitmann to make 12 replicas of the Chase Tower in Chicago for a retirement party. Initially, Heitmann planned to charge $20 per piece. However, his father, who used to own two storefronts on Chicago's Navy Pier, advised increasing the prices to $45 to cover labor costs, as each model took nine hours to print.

Heitmann generated $540 in revenue at the new price point, which he plans to save for college or use to purchase another 3D printer, according to him.

The challenges of growing a side hustle are already becoming apparent to the fourth-grader.

Since the retirement party, six attendees have placed custom orders for the Chicago skyline, which are currently in the queue. However, Heitmann's schedule is packed with math assignments and sports practices, and his parents request that he put his Etsy store on vacation mode whenever they travel.

"Chris, Heitmann's father, states that his son hasn't had time to accommodate requests for other buildings due to his school, MLB training, and 8 p.m. bedtime."

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