How wood molds create unique glass products.
Wood and glass—two natural materials that, when combined, create something truly unique. In Finland, where craftsmanship and sustainability go hand in hand, the use of wood molds in glassblowing is a time-honored tradition. The texture and grain of the mold leave an organic imprint on the glass, ensuring that every piece is one of a kind.
Glass products made with wood molds offer a distinctive aesthetic that cannot be replicated. The natural textures and patterns of wood leave an imprint on the glass, resulting in one-of-a-kind pieces. This technique bridges craftsmanship and materiality, creating glass objects that tell a story of both fire and nature. The process of making these molds is meticulous, requiring careful wood selection, precise machining, and expert glassblowing.
The first step in creating a wood mold is sourcing the right material. In Finland, we prioritize using locally sourced wood, ideally from trees that have already been felled for other reasons. The type of wood is crucial, as it must withstand the extreme conditions of molten glass while retaining its structural integrity for multiple uses.
Certain characteristics make some logs more suitable than others. The ideal wood has minimal knots, as branches create inconsistencies in the grain that can lead to weaknesses. Additionally, the wood must be free from cracks, which can be difficult to determine before cutting but may cause the mold to break prematurely. Once selected, the wood is cut into appropriately sized blocks, known as "pölkky," and submerged in cold water. This soaking process prevents drying cracks and extends the mold’s lifespan once in use.
Once the product has gone through an extensive design process, its finalized shape is translated into a 3D file. This file serves as the blueprint for machining the wood mold using a 5-axis CNC machine. The mold consists of two halves that form the negative shape of the final glass piece.
The precision of CNC machining allows for intricate detailing, ensuring consistency across multiple glass pieces while preserving the organic qualities of wood. Even with modern technology, adjustments and refinements are often necessary to achieve the best possible outcome. After milling, the wood mold is carefully finished, ensuring that the interior surface is smooth and free from irregularities that could impact the final glass form.
Blowing glass into a wood mold is both an art and a science. The mold must be thoroughly soaked before each use to create steam, which acts as a cushion between the molten glass and the wood. This steam prevents immediate burning and prolongs the mold’s usability, though each mold gradually wears down with every piece made.
The burning of the wood leaves subtle textures on the glass, creating a signature aesthetic that cannot be replicated by metal molds. As the glass expands within the mold, it takes on its final form, capturing the organic imprints of the wood. This process requires exceptional skill from the glassblowers, who must work swiftly and precisely to shape the glass while it is still malleable.
Our glass products are crafted in Riihimäki, Finland, by the skilled artisans at Lasismi. Their expertise ensures that every piece reflects the beauty of this traditional yet innovative process, where wood and glass come together to create something truly unique.