Can anyone please point me in the right direction on how to bond together a broken glass lampshade? It's a downlighter so it resembles a 'jam jar' with the top threaded coller being snapped clean off. I have tried traditional well known brand glass glue - which sets in sunlight - this seemed to work fine until the heat build up of the light fitting broke the bond. I really don't want to have to replace the wall lights & the ceiling lights if I can find a glue that will resist the heat well enough? Thanks.