moldblown

Moldblown, also spelled mold-blown, is a glassworking technique in which molten glass is gathered on a blowpipe, placed into a mold, and inflated to fill the mold cavity. The mold shapes the exterior form and may impart texture or pattern to the surface. Moldblown forms can be produced with single-piece or multi-part molds, and artisans may turn or reheat the piece during shaping to achieve the desired profile. The process is distinct from free-blown glass, in which no mold is used.

The typical sequence involves gathering molten glass, applying a mold release, closing the mold around the gather, and inflating the gob so the glass expands to the mold walls. After achieving the desired shape, the piece is shifted from the mold and finished, trimmed, and annealed to relieve stresses. Molds used for moldblown work are commonly made from metal or ceramic materials, and may bear textures or patterns that are transferred to the glass surface.

Historically, moldblown glass has been used in various cultures to produce standardized shapes such as bottles, bowls, and decorative vessels. In antiquity and in later periods, it allowed more rapid production of uniform forms compared with free-blown pieces. In modern studios, moldblown techniques are often taught as a foundational method in glass education and are used for both utilitarian wares and artistic objects.

Advances include the use of precision molds, release agents, and controlled annealing to improve consistency and reliability. Moldblown work remains a recognized method within the broader field of glass shaping, valued for efficiency, surface texture options, and the ability to reproduce a standard shape while preserving the handcraft imprint of the maker.