Things You'll Need
Black liquid tape
Carbon graphite powder, very fine
Tuluol or toluene solvent
Conductive ink is exactly what it sounds like: A colored liquid that transmits or conducts electricity. You're not likely to dip conductive ink out of an inkwell, though. The conductive particles must be transported within a non-conductive medium that dries or reduces once applied, which then stacks the conductive particles--usually carbon graphite powder or fine metallic flakes--in contact with each other, allowing electricity to be conducted throughout the expanse of conductive ink.
Work in a very well-ventilated area--outdoors if possible--and wear gloves to protect your hands from the solvents you're using and safety goggles to protect your eyes.
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Mix three parts carbon graphite powder to two parts liquid tape and six parts Tuloul solvent together in a glass container.
Use a paint brush or sponge brush to paint the conductive ink you've created onto your target surface.
Wait until the ink is completely dry to the touch--this should take half an hour or less.
Add clear cement adhesive to create a thicker conductive glue if you so desire. Most of the materials you need should be available at local hardware stores; carbon graphite powder is often sold as a lubricant. You can use fine silver or copper flakes in place of graphite powder if you wish.
Never work with these materials in an enclosed area; the fumes are dangerous.