Artist and inventor Paddy Bloomer has a genius for transforming seemingly random junk into strange, witty creations – "mechanical curiosities and improbable devices", as he calls them. There is always something joyous and playful about Bloomer's work: it's almost guaranteed to bring a smile to your face. There's his pedal-powered karaoke system, built around an old Sinclair C5 ("For technical reasons, it only seems to play 1980s music," he claims) and his candy-floss bicycle: the harder he pedals, the more evil-looking smoky blue floss it makes.

Or how about an electric knife and fork, for the fully electrified dining experience, cooking and eating in one go? Demonstrating his technique on a plateful of charred and smouldering gherkins, Bloomer marvels at how the electrolysis really brings out the flavour.

One of Bloomer’s most recent adventures involved making hybrid rockets fuelled by whin bushes and nitrous oxide, better known as laughing gas. Video footage, taken by a friend, shows the artist clad in a fireproof silver coat, lighting the device with a propane blowtorch. The set-up looks worryingly rickety, but the effect is dramatic: with a whoosh of white-hot flame, the rocket shoots up and away, zigzagging against the skyline like a demented bird.

So, why make a whin-powered rocket? “Well, whin bushes take me back to my childhood, growing up in the Co Down countryside,” says Bloomer. “We were always falling into, crawling through or burning whins. They’re known for their excellent flammability. The way I see it, the whin bush rocket relieves farmers of their unwanted greenery, and it keeps the local pyromaniacs entertained.”

In the future, he’d like to build a massive rocket, the size of a grain silo. “I imagine doing it in the peat bogs of Offaly, which is the closest thing we have to an Irish desert.”

‘Mess around’

Bloomer started off by studying engineering, but not for long. “I decided I wanted to do sculpture. I wanted to waste time, mess around, not have a proper job. I’m still skint, with no job, so you might say I succeeded.”

He graduated from Ulster University Belfast in 2000 with a degree in fine and applied art, and shortly afterwards took a studio in the Lawrence Street Workshops, in the south of the city, where he is still based. The found materials he uses for his work come to him in all kinds of ways.

“I find things in alleyways. I buy stuff from Travellers. I poke my head through holes in hedges. Sometimes people just give me stuff. I got a full set of organ pipes that way.”

Perhaps Bloomer's best-known project to date is his Bin Boat, an extraordinary gondola that he made together with fellow-artist Nicholas Keogh. The boat – constructed, among other things, from an old washing machine, an oil drum, a wheelbarrow and a number of discarded street signs – was part of Northern Ireland's entry in the 2005 Venice Biennale, where it created quite a sensation as it traversed the canals.

He is currently engaged in an exhibition at the Leitrim Sculpture Centre in Manorhamilton, where he has built a “personal deployable crannog”. The crannog, a sort of floating shed, has already been out for its “sea trials” on Glenade Lake, and Bloomer says it is performing well.

Home is a canny little house on wheels, which he built himself, tucked in a corner of a farmyard near Belfast. “I’ve always found myself living in old, damp, dark Irish houses. I would move out then someone would come in and knock them down. So I decided I would build my own place, based on everything I’d learned from houses that were wrong. The only problem was I had nowhere to build it. That’s when I thought of putting it on wheels, so it could go anywhere.”

Refrigerated truck

Using the entire back section of a refrigerated truck (“great insulation, you see – it’s dry, warm, easy to heat”) as his starting-point, Bloomer got to work, with a little help from his friends. He opened up the side and added a sort of lean-to conservatory on stilts, making a light-filled sitting area. The kitchen and bedroom are in the insulated compartment, which is cleverly designed so that the fridge and the dishwasher slide away under the bed when not in use. Hot water comes from a wood-burning stove, and there’s a compost toilet. With a few plants around the front door, the Box House couldn’t be cosier.

Soon, however, Bloomer will be leaving his home behind and taking to the road, as he does around about now every year. It's music festival time, starting with Glastonbury in June and going right through to Electric Picnic in September, and Bloomer's skills are in demand. "In summertime, I live in my van," he says. In fact, he's just back from an early trip to Glastonbury where he's involved, once again, with the construction of an underground piano bar, an "obscure acoustic venue" that is one of Glastonbury founder Michael Eavis's personal festival highlights.

“From the point of view of health and safety, Glastonbury is the best to work with,” says Bloomer. “Nearly anything is possible there. With some of the other festivals, you get the impression that nothing is possible. You get these emails saying ‘no, no, no!’”

One of Bloomer’s festival specials is the build-it-yourself barn, aka “Ireland’s only nomadic agricultural outbuilding” – a temporary event space, the antidote to bland white marquees, “where the erection of the venue is as important and sociable as the goings-on within”. He brings all the bits of the barn on the back of a trailer, then invites festival-goers to help him construct it in a glorious communal barn-raising.

‘Hurricane-force wind’

Things don’t always go according to plan. Last year, Bloomer brought the barn to the Swell festival on Arranmore island, off the coast of Donegal. “We got the barn finished and I went off for a pint. Then this hurricane-force wind blew in, and I came back to find everyone holding on to things to stop them blowing away.”

There was also the time that Bloomer took his “Texas Chainsaw Hand Massager” – an adapted chainsaw with a mannequin’s plastic hand in place of the blades – to the Body and Soul area of Electric Picnic. “It’s an aggressive massage,” grins Bloomer. “It makes you relax really hard.” Bloomer showed off his pampering skills on a willing volunteer, as a bemused crowd looked on. “Somebody called security because they thought there was some kind of attack, and the massager got confiscated. I got it back later, though.”

Exploring sewers and other hidden or forbidden underground places remains an interest for Bloomer; on one occasion, again with Nicky Keogh, he attempted to cross Belfast, from the west to the east, using the city's sewer network. The pair also carried out a series of experiments with electricity, deliberately electrocuting themselves with increasingly high voltages. According to their account, a charge of 1,750 volts gives the sensation of "being hit on the elbows with a toffee hammer", while 4,500 volts causes "fancy dancing" and a disconcerting "burnt-wiring smell inside the nose".

It might sound as though Paddy Bloomer has a reckless approach to danger, but he insists that’s not the case. “In fact, I am a health and safety enthusiast,” he says. “Given what I do, I have to be. But you have to have an element of risk in life. It keeps you on your toes.”

Basement jacks: The day the loos turned disco

Paddy Bloomer, with Nicholas Keogh, installed an impromptu disco – complete with lights and sound system – in a sewer in Lisbon, the Portuguese capital. “It ran for one summer night, it was a big hit, and then it got closed down the next day,” says Bloomer. “We looked out the window the next morning and there was the police, the fire brigade, the city engineers and the TV cameras. They sealed off the entire street, but I don’t think they ever worked out who was responsible.”

For Bloomer, the Lisbon sewer disco wasn’t so much about making an artwork as making a story, a myth that would be told and retold, many years later.

“Locals reported that there was music coming out of their toilets. I like that.”

• Personal Deployable Crannog is at the Leitrim Sculpture Centre in Manorhamilton, Co Leitrim until Saturday June 3rd. leitrimsculpturecentre.ie