I don't know what the copper tape is used for in stained glass, but the idea just popped into my head one day and I did a search on-line and found it in many places. I don't remember which one I purchased it from. It's MasterFoil Plus from Venture Tape. The roll I purchased is 3/8" wide by 36 yds long. I also don't know if Michaels carries it. The glue on the back of the tape is heat resistant so it is perfect for this use.\
Ralph