Jerry - even the Big Orange Box didn't have lead? I got a bunch in a 5-gal bucket from the chimney work I did. Probably toxic or something. No friends with Ice n' Water shield left over? Then you probably will be fine with an intelligent fitting job and some fiberous tar. Mine is Tru Bond Wet n Dry Fibered Roof Cement, from True Value Hardware. I'm sure the Big Orange has a similar asphalt and fiber compound available. Use throw-away gloves, a stiff plastic disposable putty knife, and don't get it on your clothes, unless you like them black and have a separate washing machine in your garage. It's kinda hard to stir up, so do that on the ground with a stout stick - it's no fun trying to fish out a broken paint stick - someone told me about that happening to them. /forums/images/graemlins/blush.gif /forums/images/graemlins/grin.gif
Since your joint is up high, there's not going to be a lot of water get in there anyway. And that asphalt product is good to have around for miscellaneous leaks and things that need pluggin'.
Copper is lovely, but I've never worked with it. It's probably as good as lead if you can mold it - I'd use a plastic hammer and go easy.