The existing pens are intended only for minor PCB repairs. They are terribly expensive, as in $100/oz, have high resistance, and cannot be drawn with smoothly (

The existing pens are intended only for minor PCB repairs. They are terribly expensive, as in $100/oz, have high resistance, and cannot be drawn with smoothly (like a pen). They are also not intended for the kind of flexing that you see on a piece of paper. Example (0.3oz for $30): http://www.amazon.com/gp/aw/d/B000B5YDT8 http://www.amazon.com/gp/aw/d/B000B5YDT8 Historically, you've been better off using conductive silver thread for flexible and on-the-fly circuits. Still expensive and resistive, but tolerably so. Example (82 ohms/ft, $5/yd): http://www.sparkfun.com/products/8544 http://www.sparkfun.com/products/8544