Making Bias cut tape is easy.

Just take 'glass cloth of the correct weight and cut it diagnally. it is easier still if you have one of those roller knife cutters available in fabric stores. just lay the 'glass on a clean peice of plywood and roll the cutter diagnally across the cloth. you can control the width by how far apart you make the cuts.

you will only get lengths of up to 4-5 feet or so depending on the width of the cloth.