Long after his wife and daughter have gone to sleep, Sheldon Gilman can be found downstairs in his Redbourn home tinkering with a 3D printer.

https://www.youtube.com/watch?v=AYZKfBneOFU

By day, he works in IT; he is a father, a husband, a video-game fanatic. But by night, in the small hours of the morning, Sheldon builds superhero armour.

“I get very little sleep,” he says. “Family does come first but at the end of the day when they’ve gone to bed, I do this.”

By ‘this’, Sheldon, 35, means tinkering with designs for a bespoke, tailored Iron Man suit to rival the one worn by Robert Downey Jnr in the blockbuster films – complete with electric fans, a camera and Bluetooth integration.

“The fans are to keep my head cool,” he explains. “The camera will be connected to a tiny screen in front of my eyes so I can see out.”

And the Bluetooth? I ask, anticipating laser-beams or some other remote-control weapon.

“No,” he laughs “That’s so I can answer my phone.”

Each part of this full-body suit – Sheldon’s second incarnation of home-made Iron Man armour – is being painstakingly assembled from designs downloaded from the internet.

Helmets, shoulder pads, a chest piece, forearms, abs, waist, thighs, shins and boots – each piece will be tweaked to fit before it is built on his dining room table.

Sheldon says: “This is the first one I’ve done in fibreglass, so it’s taken me a good few months, simply because I’m doing it as I come home from work and I only get a couple of hours here and there.

“But if I were to do it constantly it would probably take me a week, from start to finish - just to do the helmet.”

On top of a full-time job in IT, caring for his family and training as a video-game artist with Train2Game, Sheldon somehow squeezes in this time-consuming hobby.

His drive stems from a love of comic books: DC, Marvel and Manga. So a few years ago when Sheldon’s wife, Parveen, bought him and his brother tickets to Comic-Con, the fan convention held annually in London, Sheldon was like a kid in a sweet shop.

“We loved it so much,” he remembers. “I thought, ‘I really want to come back in cosplay [a portmanteau of costume play - the term used to describe the act of dressing up as genre characters].”

“But I’d never done anything like this before. I watched some YouTube videos. Some of the guys on YouTube are very good and they give you all the help you can ask for.”

First, the design is printed onto paper, folded and glued into shape.

Sheldon explains: “I take those parts and glue them together like origami. I can make any structure like that.

“Then I use fibreglass resin which makes it almost solid - there’s a little bit of wiggle room in there.

“Then I use the fibreglass and it goes rock-solid. But I’m not quite done - I have to put body-filler on it to smooth it out.”

After a sleek paint-job, the finished product is a glossy, lightweight piece of superhero armour, tailored to fit and packet with gadgetry.

The price comparison website, MoneySupermarket, calculated the cost of the real Iron Man’s suit at $1.6 billion. Sheldon’s fibre-glass replica (which, I have to say, looks at least as good) will have cost less than £800 when completed.