Electroforming involves electroplating a thick shell (several millimeters thick) onto a master pattern. Before plating can commence, the surface must be made electrically conductive.

A simple technique to achieve this is to spray a conductive lacquer onto the model. After plating, the shell is removed and then backed with a suitable material.

This is a technique used to produce tools for shoe soles with complicated patterns from original wax models. Nickel is a common material for electroforming and has good thermal conductivity and strength. The process gives faithful reproductions of the master, but can be limited when plating into deep narrow slots or holes. Electroplating builds up more material on exterior corners and narrow slots can be closed at the top before they have plated enough at the bottom. This can be partially overcome by reducing the current, but this increases the time to produce the shell.

Express Tool (Warwick, Rhode Island) is developing an electroforming process that it plans to commercialize. The company typically produces the patterns by machining graphite. This material is an excellent conductor and it machines many times faster than aluminum. Another benefit to using graphite is that it serves as a natural release due to its lubricant properties – making it easier to separate it from the nickel shell.
An advantage of electroforming is that it is very good at the reproduction of detail. Disadvantages are that the process is not particularly fast and it’s not possible to do deep slots or holes.