Mold making –
From one-off production to series production.
Tools for repeatable glass production
Glass is inherently a free material—it can be blown, hammered, and shaped freehand, without ever being touched by a mold. But as soon as an object needs to be reproducible, as soon as production volumes increase, or geometries must be precisely defined, the logic changes fundamentally. A good mold reduces waste, ensures consistent quality, and makes mass production economically viable.
At Design Studio Fusión, we create molds for every aspect of this scale—from the initial plaster prototype for five test variations to the CNC-milled graphite permanent mold for mass production. The choice of mold material is crucial: it determines temperature resistance, lifespan, surface quality, and the overall cost-effectiveness of the production process. We have extensive practical experience with all four processes and offer comprehensive, material-independent consulting—because the right mold is the foundation of every reproducible glass object.
Plaster Molds
Rapid prototypes and small production runs for glass processing
Plaster is the most direct molding material in the glass studio. It is quick to work with, inexpensive to produce, and precise enough for most kiln-forming applications. In slumping, a glass plate is placed over or inside a plaster mold and fired in a kiln at controlled temperatures to achieve the desired geometry—the plaster mold thus defining the final shape.
For prototypes, plaster is the first choice: A new glass mold can be quickly tested, adjusted, and refined in plaster before investing in more complex tooling. For small production runs of five to ten pieces, plaster is also the most economically viable solution—the mold easily handles these quantities without justifying the expense of a metal or graphite mold.
We build plaster molds for slumping, fusing overlays, casting negatives and as a basis for slip-casting processes in the ceramics workshop.
Suitable for: Glass prototypes, small series of 5–10 pieces, slumping and fusing applications, ceramic slip casting, initial shape tests before investing in permanent tools
Silicone Molds & Master Models
Master molds for reproducible subsequent processes
Silicone is not the final tool—it's the bridge. A 3D-printed or handcrafted positive is molded in silicone, creating a flexible master mold from which other materials can be taken: wax for the lost-wax casting process, resin for master models, and plaster for subsequent molds.
In the context of the glass studio, this step is particularly relevant for investment casting: The wax model—the starting point for every metal casting and certain glass casting techniques—is created from the silicone master mold. A precise silicone master model enables the reproducible production of identical wax positives and thus consistent casting quality across multiple runs.
Furthermore, mouth-blown glass unique pieces or handmade originals can be molded in silicone — to secure the geometry, as a basis for subsequent processes or to reproduce an object in another material.
Suitable for: Master molds for lost-wax casting, molding of unique glass pieces and 3D positives, base for resin and plaster subsequent molds, securing original geometries
Wooden Molds
Rotationally symmetric shapes directly at the furnace
Wood is one of the oldest and most specific mold materials used in glassmaking. Using wet wood against molten glass is a direct, immediate technique: the mold is pressed against the hot glass during blowing, and the resulting cushion of steam dictates the geometry without adhering to the glass.
The crucial criterion: wooden molds only work for rotationally symmetrical objects. Bottles, vases, spheres, cylinders—any shape that rotates around the longitudinal axis of the blowpipe can be defined with a wooden mold. For fixed blow molds—objects that are blown into a closed mold—wood is unsuitable. Metal and graphite molds are used for these.
We turn and manufacture wooden molds for direct use in the glass studio — tailored to specific geometries, wall thicknesses, and production requirements. The material is moistened before use and kept continuously damp during the working process.
Suitable for: Rotationally symmetrical glass shapes, free blowing with molding aids, vases, bottles, bowls, cylinders — not for solid blowing processes
Metal & Graphite Molds
Durable tools for large series and mass production
As production volumes increase, molds must keep pace. Metal and graphite molds are the glass studio's enduring tools—precisely manufactured, thermally stable, and designed for hundreds or thousands of repetitions. They form the basis for any more industrialized glass production that goes beyond handcrafted items and small batches.
Graphite is the preferred material for blow molds and casting tools: it conducts heat in a controlled manner, does not stick to the glass, is easily machinable, and retains sharp contours even with repeated use. Steel is used where mechanical strength and durability are paramount—for pressed glass, permanent molds, and tools requiring high clamping force.
Both materials are CNC-milled in-house — directly from CAD data, with reproducible precision and without any manual intermediate steps. The combination of digital toolmaking in the 3D lab and physical manufacturing in the metal workshop makes this process fully replicable in the studio — from the file to the ready-to-use form.
Suitable for: Large series and mass production in glass, fixed blow molds, blow molds for reproducible geometries, press glass tools, permanent tools for industrial glass applications