I use .012 braided control line flying wire powered by an Astro Flight 110d nicad charger and a 2 amp 12 v power supply. You can put the charger into test mode and then accurately adjust the power output to suit the wire, foam, bow and cutting style. I have also used a simple hobby battery 12 v charger like you use to charge your flight box battery. The Astro Flight charger can be had at swap meets and auction sites for less than $20 as few eflight types use nicads anymore.
For a bow I have used 1/4 inch dowels with moderate success but am now using a fiberglass RC pushrod which works great for smaller wings.