Based on the provided reference, making glass blowing molds involves creating a wax model, building a containment box around it, and then heating the mold to a high temperature before blowing glass into the resulting void.
Creating molds for glass blowing allows artists to produce intricate shapes and repeating forms that would be difficult or impossible to achieve by free-blowing alone. While various mold-making techniques exist, the method described in the reference outlines a process similar to lost-wax casting, adapted for glass.
The Essential Steps from the Reference
The core process described in the reference can be broken down into three key stages:
- Model Creation: Begin with a paper shape and fill this shape with microcrystalline wax. This wax-filled paper shape serves as your positive model.
- Mold Preparation: Fix the gate (spru), which is the channel through which the molten glass will enter the mold, to your wax shape. Build a box around your shape using components called coddles and secure it with clamps. This box will contain the mold material (not explicitly mentioned in the reference, but implied to be poured around the wax shape).
- Firing and Blowing: Heat the mold to 1000ºF. Once the mold is ready, you can blow hot glass into the void created by the removed wax. After the glass piece has been annealed (cooled slowly in a controlled manner), gently remove the mold material from the finished glass object.
Understanding the Components
- Paper Shape: This is used initially to form the desired shape using wax. It acts as an outer boundary or guide for creating the positive wax model.
- Microcrystalline Wax: A flexible type of wax often used for modeling and sculpting. In this process, it is used to create the detailed positive form that the final glass piece will replicate.
- Gate (Spru): A channel or opening attached to the wax model. When the mold is fired and the wax melts away, the spru becomes the entry point for the molten glass.
- Coddles and Clamps: These are used to build the outer walls of the mold container (the "box") that holds the mold material securely around the wax model during its preparation and firing.
- 1000ºF (Fahrenheit): This high temperature is necessary for several reasons: it melts out or burns away the wax model completely, hardens the mold material, and preheats the mold so that the hot glass doesn't crack it upon contact.
Step-by-Step Summary
Here is a summary of the process as detailed in the reference:
| Step | Action | Purpose |
|---|---|---|
| 1. Modeling | Start with a paper shape; Fill the paper shape with microcrystalline wax | Create the positive form the glass will take |
| 2. Containment | Fix the gate (spru) to the shape; Build a box around the shape with coddles and clamps | Prepare for pouring/applying mold material (implicit); Create entry point for glass |
| 3. Execution | Heat the mold to 1000ºF; Blow glass into the void; Anneal glass; Gently remove mold | Prepare mold; Fill void with glass; Controlled cooling; Uncover glass piece |
This method, focused on creating a wax positive and using it within a mold structure heated to high temperatures, allows for the reproduction of specific designs in glass.
