Art reviews: José Antonio Hernández-Diez | Levi Hanes

"FAT is good." Discuss. It all depends on your perspective: whether you're an Arctic explorer on the edge of starvation or a catwalk starlet whose every calorie is her enemy. But of all the possible uses and misuses of fat in the history of mankind, its properties as an artistic material are hardly viewed as significant.

Fat, however, does merit a few paragraphs in the history of art. Joseph Beuys used it often as one of the palette of materials he associated with his rescue by Tartar nomads when his plane crashed in the Crimea – a story which may or may not have been augmented in the telling.

There is an echo of Beuys's convoy of sledges, The Pack, in Jos Antonio Hernndez-Diez's collection of skateboards made from fried pork fat. But while Beuys sought to imbue his materials with significance, Hernndez-Diez does the opposite. His lengths of fat are a popular snack sold on the streets of his native Venezuela, they are nothing more than consumables.

In this series of works – separately and collectively titled Fat Is Good – the skateboards occupy the gallery like disaffected youth, hanging out in the corners, lolling on the tables, part anthropomorphic, part sculptural objects. The show's impermanence is obvious: some "boards" have dried out and twisted since they were made, others appear to be slowly congealing.

He expands his ideas in three film works. One shows a skateboard being enthusiastically chewed by a dog. In another, made specifically for Transmission, a board is trundled round the streets near the gallery, propelled by an unseen hand. Soon it begins to look like a little creature piloting its own way through a big, nasty world, struggling up slopes, circumnavigating dog turds.

There is a welcome lightness to Hernndez-Diez's work that is also present in the work of Levi Hanes, a graduate of last year's MFA course at Glasgow School of Art. Hanes was the first to be chosen for an annual month-long residency in Tramway 5, to be followed by an exhibition, and it looks like he had a ball. His imagination was clearly captured by the public aspects of the project – the artist can be watched at work through the long windows and via camera-feed to the caf – and this fed into the work he made.

Realising that it takes longer than a month to produce a finished body of work, he has left the gallery as a mock-up of his studio, with his notebooks, pot plants and a soundtrack of the music he was listening to, and in it has exhibited his ideas, doodles and half-developed thoughts.

This might seem like cheating if he were not so disarmingly honest about it. Instead, it's fun to explore the varied threads of his enthusiastic creativity, from a scratch in the paintwork on the wall to a weighted chair attached to dozens of helium balloons, a stunt reminiscent of veteran Swiss artist Roman Signer. There are also five large paintings, four of them tantalisingly stacked face-first against a wall.

The most resolved works are the short films using a rectangle painted on a wall, which becomes a screen on which images are projected. In one, Hanes is painting the rectangle with a roller, in decorator's overalls, while the image on the wall changes from a cityscape to a Van Gogh painting. In another he keeps up a tennis rally against it. This playfulness, albeit with an underlying rigour, is all too rare, and it will be interesting to see how well these qualities bear out in a finished body of work.

Alex Gross and Sandy Smith, at Collective Gallery as part of the New Work Scotland programme, are also recent graduates of Glasgow School of Art. This show is their first collaboration and, as such, has a sense of trial and error about it, as two practices meld into one.

All the works here result from a road trip taken through the western United States, and are on some level concerned with how contemporary art engages with large and dramatic themes, from the tawdry glitz of Las Vegas to the majesty of the Rocky Mountains.

Key are the two film works, each an hour long, though with the action confined to the final few minutes. Waiting for Recurrence records the sounds of a group of tourists in Yellowstone National Park waiting to watch the geyser Old Faithful erupt. The excited murmuring and chattering continues while the geyser does precious little, an evocation of what it is to be a tourist who travels thousands of miles for an advertised experience and is not leaving until it happens. In the end, the geyser erupts, and the crowd is suitably impressed.

Showing long films with long periods of inaction deliberately tests an audience's patience, but it's a daring move. Overall, this show is uneven in texture. The concrete sculptures are unengaging, while the large psychedelic glitter sculpture, squeezed in next to a second contemplative film, is in danger of drowning out the rest by sheer force of its personality.

&149 Jos Antonio Hernndez- Diez runs until 31 January; Alex Gross & Sandy Smith until 7 February; Levi Hanes until 8 February.

Art reviews: José Antonio Hernández-Diez | Levi Hanes | Alex Gross and Sandy Smith