Azure Wave — The Making of a Cast Glass Sculpture

Azure Wave” — A kiln-cast glass sculpture created from hand-cut Bullseye glass blocks, fused and annealed over two days in a stainless-steel mould. The deep ocean blue glass captures and reflects sunlight, projecting rippled shadows across the windowsill.

There’s a quiet magic to working with glass — a material that is both fragile and eternal, fluid and solid, responsive yet unpredictable. Our sculpture “Azure Wave” embodies that duality: a deep ocean blue crest frozen in motion, shaped entirely through the process of kiln casting.

The journey begins with Bullseye glass, chosen for its exceptional clarity, consistency, and rich colour range. Unlike blown glass, where molten material is gathered on a pipe and shaped by hand, cast glass begins life as solid sheets or billets that must be painstakingly cut into shape. For Azure Wave, each block of turquoise-blue glass was cut by hand, ensuring clean, straight edges and even thicknesses. The size of each block determines not only the flow of the molten glass but also the final depth and intensity of colour once the piece has cooled.

Preparing the mould

The sculptural form is created using a stainless-steel mould designed to withstand high kiln temperatures without warping. Stainless steel is an ideal choice for complex castings as it maintains its integrity through repeated firings and can be reused many times. Before assembly, the entire interior of the mould is carefully coated with boron nitride, a high-temperature release agent that acts as a separator between the steel and the molten glass. Without this essential coating, the glass would fuse permanently to the metal, rendering both unusable.

Once coated and dried, the mould becomes a kind of three-dimensional sketchbook. Each piece of hand-cut glass is arranged within the form like a puzzle, stacked and angled until the desired rhythm of movement is achieved. In Azure Wave, the composition curves upwards from the centre, creating the sense of a rising swell caught mid-motion.

Into the kiln

The loaded mould is placed inside a large flatbed kiln, where temperature and timing are everything. The firing schedule is designed to allow the glass to first relax, then fuse, then stabilise without internal stress. The process takes roughly two full days from start to finish.

The kiln is first slowly heated to around 510 °C, where it’s held for an hour. This crucial stage allows the glass to equalise in temperature, ensuring that no area expands faster than another — a common cause of cracking. Once stable, the kiln is then allowed to heat as fast as possible up to the top temperature of about 790 °C. At this point, the glass softens and begins to slump and fuse, filling every contour of the mould.

After reaching that molten peak, the kiln temperature is dropped rapidly back to 510 °C, where it remains for about three hours. This phase — known as annealing — is where the structure of the glass realigns itself, releasing the stresses that build up during heating and cooling. Finally, the kiln temperature is gradually reduced over many hours until the sculpture reaches room temperature once again.

The importance of annealing

Annealing is the unsung hero of the glassmaking process. If the glass is not properly annealed, microscopic stresses remain trapped within the material. These tensions may be invisible at first but can later cause spontaneous cracking, even weeks or months after completion. A piece that has not been evenly cooled can literally shatter on its own shelf. In complex cast forms like Azure Wave, which feature thick sections and varying cross-sections of glass, proper annealing ensures that the interior and exterior cool at the same rate. It’s a delicate dance of heat, time, and patience — one that separates success from disaster.

Finishing and patination

Once fully cooled, the sculpture is removed from the mould and carefully cleaned. Edges are refined, and the final stage involves the addition of a subtle iron-oxide patina applied to the outer rims of each crest. This surface treatment adds depth and contrast, darkening the edges and accentuating the wave-like curvature. The effect is almost geological — as though the blue glass has weathered naturally over centuries.

When placed in sunlight, Azure Wave transforms. The transparency of the Bullseye glass allows the light to pour through, projecting rippling shadows and reflections that shift throughout the day. It’s this interplay of light and form that makes kiln-cast glass so captivating — a perfect balance between control and chance, discipline and surprise.

Every sculpture is a conversation between the artist, the kiln, and the glass itself. The materials may follow physics, but they also follow intuition. Azure Wave is the outcome of that dialogue — a piece of glass that holds the memory of heat, the patience of time, and the calm of the sea itself.