LONDON Skateboarders are known for high-flying tricks, from jumping off of ramps to shooting down railings, but now one British designer is touting an environmental trick of his own, by using old plastic bags to make boards.

Around 1,500 plastic bags, or 1.8 kg worth (roughly 4 lbs), are used to make a skateboard deck by 22-year-old Jason Knight,, a Brunel University design student.

The boards are made by putting the plastic in a machine which heats it to around 200 degrees Celsius (roughly 400 degrees Fahrenheit) for up to two hours, then uses pressure to mould it into a solid object.

“We all know recycling is the right thing to do,” Knight told Reuters. “I thought if people have a tangible reward like a skateboard (from) recycling it would incentivise people to do so.”

The plastic decks are fitted with conventional axles and wheels. Decks are normally made out of plywood, and typically cost anywhere between 40-60 pounds ($50-75).

Knight hopes his idea could be implemented to encourage young people to collect enough waste plastic in exchange for use of a press similar to the one he built.

English retailers sold 1.1 billion plastic bags to customers in the six months after a 5p charge was introduced in October 2015, a drop of around 85 percent on the previous year, according to UK government data.

Knight is not a skateboarder himself, so he took one of his finished creations to a skate park on London’s South Bank for others to field test.

“People really like the idea; no one’s seen anything like it before. They like the flexibility, it means you can jump higher,” said Knight, adding he’s picked up a few tips on where to improve the design.

“The thing I need to address most is the weight; it’s important for doing tricks that I try and bring the weight down.”

(Writing by Mark Hanrahan Editing by Jeremy Gaunt.Editing by Jeremy Gaunt)