36 Gauge .005" tinned copper wire. Used as a counter-wrap on homemade imitation thermalite for ignition and rapid propagation. Supplying only one wire will increase the burn rate 80% to 90%. Two would create explosive reactions. Before coating string, place a small wire 'cup hook' in a power drill and mount the spools of tinned copper wire and 16-2 cotton *string on a wooden dowell so they will spin off freely. Pinch the two together and use the drill to wrap them together as shown. For longer lengths, walk away from the drill then have someone turn the drill off. Tape both ends to secure them together for use. *I use Mercerized cotton string available in any Walmart sewing section or other sewing supply stores.