3M makes a lead foil tape which I have seen used to mimic the lead came of a
prisma glass storefront transom, should work here.
3M™ Lead Foil Tape 422
Dark Silver, 5.9 mil (0.15 mm) lead foil backing with
acrylic adhesive that
offers outdoor and long aging performance
characteristics.
ADDITIONAL INFORMATION A good general purpose
moisture barrier, electroplating maskant and
sealant. Applications include decorative simulated
lead-glass window appearance from both sides
of tape, while providing resistance to weather and
sunlight giving long age performance.
- From 3M's Speciality Tapes amd Products
Division.
--
F. Mitchener Wilds, Senior Restoration Specialist
Restoration Branch
State Historic Preservation Office
919/733-6547
http://www.hpo.dcr.state.nc.us
***My opinions may not be those of my agency.***