Electroforming / Electrotyping
Electroforming or Electrotyping is a metal forming process. Copper or nickel is dissolved under an electrical current in a electrolytic bath and deposited atom-by-atom onto a conducting form (mold) which is removed after electroforming has taken place. This last step is in contradistinction to electroplating, in which the deposit's adhesion to the substrate is of utmost concern.
In electroforming the deposit can be much thicker and exist as a self-supporting structure after the negative is removed. Just like a metal cast.
Due to its ability to replicate a surface perfectly, atom-by-atom without loosing details, electroforming has taken importance for example in fabricating the master for vinyl records and today in fabrication of micro and nano scale parts such as micro-electronics and chips or - again for the master of CD’s, DVD’s.
What we do:
While this process is mostly being used in industry with small dimensions and very high precision requirements, I searched it for the fabrication of Rudolf Stingel’s “Celotex Panels” reliefs in dimensions of 4 by 8 ft / 122 x 244 cm.
While I couldn't find a company doing that, I found the missing knowledge through an older guy in Serbia, with whom I founded the company “Jan Eugster d.o.o.” in Belgrade. Since that time we have developed and adjusted the process to our own specific needs and demands.
Today we are casting molds in suitably developed rubbers, similar to the molding in lost wax casting process.
After the mold is created and prepared we apply a conducting layer with a mirroring technique. The prepared mold is connected to the negative pole of a transformer and submerged into an electrolytic tank. Copper anodes are dissolved in the electrolyte hooked to the positive pole of the circuit. Electroforming starts.
After the demanded layer is reached (on Scott Myles “Habitat” for example, this layer was about 2mm) we stop the process, mount a steel frame into the backside to make the cast rigid and detach the rubber mold from the surface. The surface is a perfect copy of the model.
Size:
By now our infrastructure is able to fabricate up to 230 x 200 cm reliefs in one piece (no welding - no seam). With adjustments of infrastructure it is possible to produce larger electroform casts, without mating and without any compromise of the surface quality.
Layer:
The deposited layer is controlled by the time and speed of the electrofoming process. We can produce extremely thin casts- like foil, or cm’s of thickness- depending on the project & need. In this process the copper grows at a rate of about 0.5mm per day.
3rd dimension:
The process is limited in 3rd dimension, as it follows the basic law of electricity and therefore is not competitive with metal casting.
Further:
Unlike any technique of metal casting, in electroforming no heat or melting of metal is involved. The process takes place in electrolyte (copper sulfate) at a temperature of 26°C. Therefore many different materials could be input into negative without being lost during the process. This objects are framed by copper as a result.