Enameled cast iron is made by first forming a cast iron piece, then preparing its surface through sanding and shot blasting, and finally applying a durable enamel coating.
The journey from raw cast iron to a finished enameled piece involves several key stages, focusing heavily on preparing the surface to ensure the enamel coating adheres properly and lasts for years.
1. Casting the Iron
The initial step involves casting molten iron into the desired shape using molds. This creates the basic structure of the cookware or piece.
2. Surface Preparation: Sanding and Shot Blasting
Once the cast iron piece has cooled and been removed from the mold, the surface needs significant preparation before enameling.
- Sanding: The piece is typically sanded to smooth out imperfections and refine the shape.
- Shot Blasting: Following sanding, the piece undergoes a process called shot blasting. As highlighted in the reference (1:38 - 3:25), this step is crucial. It involves propelling abrasive particles at the surface. This process serves two main purposes:
- Removes Oxidization: Shot blasting effectively removes any rust or oxidization that may be present on the cast iron surface.
- Creates Porous Finish: Importantly, it creates a rough, porous finish on the surface. This texture is essential to "allow a good adhesion of the enamel to the surface," ensuring the enamel coating bonds strongly and durably to the cast iron base.
3. Applying the Enamel Coating
After the surface is prepared through sanding and shot blasting, the enamel is applied. Enamel is essentially a form of glass that is fused onto the metal at high temperatures.
- Multiple layers of enamel are often applied, both inside and outside the piece, to build up a robust, non-reactive surface.
- Each layer is typically fired in a high-temperature kiln, causing the enamel to melt and fuse permanently to the cast iron. This firing process creates the hard, smooth, and vibrant finish characteristic of enameled cast iron.
This meticulous process ensures the cast iron is protected, easy to clean, and resistant to rust, while also allowing for vibrant colors.
