Step 3: Etch The Conductive Fabric
Ink, paint, tape, or some other material (called a resist) is used to cover parts of the copper clad circuit board and seal it from the etchant. The etchant (usually Ferric Chloride) reacts with any copper that is uncoated and chemically removes it. So, wherever there is resist, the copper will remain. The resist is put on in the pattern of conductive traces that you want your circuit board to end up with.
The process is the same with conductive fabrics, with the exception that we are dealing with a porous woven material that is plated with copper and/or nickel. Conductive fabrics have an extremely thin plating of metal, usually over nylon or polyester. It is so thin that they can be etched in from 5 to 60 seconds. This is with a strong Ferric Chloride solution at room temperature.
Soak the fabric in the Ferric Chloride solution for the following times:
FlecTron 30-60 seconds
Nickel Mesh-60 seconds
Remove the etched fabric and rinse VERY WELL with lots of water and then blot on paper towels and hang to dry.
pic 9 shows VeilSheild fabric that has been etched with 3 conductive traces to form an almost transparent, flexible cable. Pic 9b shows the cable with conductive glue and conductive thread.
Pic 8 shows the nickel fabric with crayon resist after etching. The Ferric Chloride etches nickel nicely. Even though there are tiny gaps in the conductive traces, they conduct extremely well. The fabric was soaked in toluol solvent to remove the crayon. Soak in a glass container for about an hour and agitate it occasionally.