It has been three years since Jim Lambie made an appearance in Glasgow, and it's fitting that Forever Changes, his return to home ground, is at the heart of the Glasgow International festival of visual art. It was Lambie, alongside his fellow graduates of Glasgow School of Art, who revitalised the city's scene and granted Glasgow an ongoing international reputation as a hub for contemporary art in Europe. Without that crop of artists and their work, dubbed "the Glasgow miracle" by Swiss curator Hans Ulrich Obrist, it seems safe to say that a festival on the scale of the GI would not exist.

Typically, Lambie has chosen to kick things off with a blast. His first, arguably belated, show at the Gallery of Modern Art opens with Get Back, a brick wall placed, confrontationally, a few short feet from the entrance to the exhibition space. As an introduction to the exhibit, it works well, slapping visitors in the face with a burst of Lambie's trademark charity-shop psychedelia. The bricks are formed from fabrics torn from old dresses, with garish floral patterns clashing with outsize houndstooth checks, eye-popping geometrics and plain fields of itchy polyester colour. As if that wasn't a sufficient shock to the visual cortex, the grouting between the bricks is a queasy shade of DayGlo pink, and the wall has landed on two pairs of patent leather training shoes.

It's a defiantly ugly piece of work, and one that conjures up a skew-whiff retelling of The Wizard of Oz, with Lambie dismissing the yellow brick road as overly monochromatic and too-obviously horizontal, and recasting the wicked witch of the east as a Glasgow scally out on the town on a Friday night. While I doubt Lambie had Oz in mind when he gathered together the familiar detritus he utilises in his sculptural work, it fits the underlying theme of the show, which hints at travel to unknown lands and the navigation of treacherous seas.

This unlikely leitmotif is set in motion by The Strokes, a new vinyl-tape floor work in the long-running Zobop series. Unlike the best-known incarnations of Lambie's floors, in which brightly coloured lines of tape trace the contours of the rooms in which they are installed, this one is made of interlocking curves in black and white. This is good old-fashioned op art, with the integrity and stability of the floor upset by a curious visual effect, a strobing ebb and flow that flickers in peripheral vision, an illusion of waves in motion.

Bobbing in the black and white sea are eight cubes of concrete. Inside each block is a collection of long-playing records, plucked at random from the bargain bins of charity shops. But before they can float on to the shores of some imagined South Sea island and spark a new cargo cult, the fossilised discs will have to make it past what is arguably the best work on show here, Seven and Seven Is or Sunshine Bathed the Golden Glow.

In the form of a cresting wave, this teetering sculptural assembly is made of wooden chairs, the sort you'd find around the average pub table, precisely bisected, painted in high-gloss pastels and then bolted together willy-nilly. The structure is festooned with cheap handbags, their faux-leather surfaces obscured by shards of smashed mirror that reflect the striped floor below and the sickly shades of the chair parts from which they hang.

This is what you might call classic Lambie: everyday objects of little value have been transformed into something garish, glorious and gloriously meaningless, an act of transformation made with an absolute certainty, with objects snatched from the artist's surroundings and used as pure sculptural material.

So far, so good - but at the edges of the room, the show starts to unravel. Head Shadow is pleasing enough. The squat little construction calls to mind the off-shore interzone of the Principality of Sealand, and is made of a cheap holdall resting on a dartboard, resting in turn on a set of spray cans, which disgorged their loads of paint across the floor at the moment Lambie completed the sculpture - a none-too-subtle reminder that he is no studio-bound conceptualist but an active sculptor who works in the spaces given over to him.

Next comes The Spell, a forgettable wall-mounted cube fashioned from gilded sections of standard door panels; then, on the other side of the space, Warm Leatherette, which sees a bowling ball hidden inside 10 leather-jacket sleeves, sewn together to form, following the seafaring theme, something akin to a deep-sea polyp or unexploded mine. Both are completely overshadowed by Seven and Seven Is and feel forced, as if Lambie is filling space, adding unnecessary adjuncts to the main business that fills the central strip of the gallery's main hall.

Between these two, propped against a pillar, rests A-Side Forever Changes B-Side The Gate. The lengthy title is a rather weak joke. One side, facing out into the room, shows a redacted image of three men - presumably members of Love, Arthur Lee's psych-rock outfit, whose song titles Lambie has lifted for various pieces in this show and for the show title itself - framed with cutout flowers. The other is, well, a gate, of the garden variety, painted bright red. Aside from the over-literal gag, the work falls flat thanks to the overly explicit musical reference. Lambie has been pegged by some as a latter-day Kandinsky, a sort of sculptor of music - but he has always argued convincingly that, just as his use of easily recognised materials is largely incidental to the finished work, so the co-opting of titles from the hip end of the pop canon signifies nothing more than the fact he is surrounded by music and naturally looks to familiar texts to fashion the textual elements of his works. By reconfiguring the 7" single, complete with carefully constructed A-side and an afterthought of a B-side, Lambie's claims begin to look a little disingenuous - and, more importantly, this work is stripped of the impenetrable mystery of its betters.

Forever Changes is an awkward, off-kilter show. The loose, suggestive nautical theme provides a context that binds the best work together, supported by the shifting floor work that Lambie uses to mark his territory, and the best pieces - the ugly wall, the wave of chairs, the concrete blocks - sit well together, engaged in a bright, chaotic conversation. It is a shame he felt the need to go further, lessening the impact of the pieces at the heart of his show with the second-tier efforts that surround them.

Jim Lambie: Forever Changes is at the Gallery of Modern Art, Glasgow, until September 29.