Binari 7/32 In., 1 mil Black Back Copper Foil is a good mid-range size for copper foil work. Specially made in South Korea, BiNARi Glass Studio® Copper Foil Tape is new, innovatively lightweight, and artist-friendly. It features durable tack with strong heat-resistant adhesive, making it the excellent choice for producing a smooth, uniform solder bead for stained glass projects. Black backed foil is ideal for projects where black patina will be used to color the finished solder lines.
 
Foil measures 7/32" wide and 1.0mm thick.
 
Pro Tips:
Once you have applied the foil to the glass, gently fold over the the foil and then burnish it flat.
When using transparent glass and bevels, choose your foil based on the color of your solder seams.
Choose copper backed foil if using a copper patina
Choose black backed foil if you are using black patina
Choose silver backed foil if you are leaving your solder silver