A broken glass lamp fixture is not always a lost cause. The best candidates for repair are those fixtures that are broken into the fewest pieces. There is virtually no way to reattach slivers, chips and dust. The best glue for glass repair is UV light glue used by many glass repair professionals. But even when professionally glued, the lamp fixtures will likely have visible hairline fractures where broken pieces have been glued together.
Wash the glass pieces with warm, soapy water or silicon-free glass cleaner. Take care not to cut yourself or break the pieces further. Allow the pieces to air dry completely.
Lightly sand the edges you intend to glue together with 100 grit sandpaper. Sand just enough to roughen the edges.
Arrange the pieces in the order in which you're going to glue them together. Make sure you know where each piece goes before you start gluing.
Apply glue to the edge of one glass piece. Follow the manufacturer's instructions for application methods and amounts.
Press the edges of the two pieces to be glued together. Press them firmly until glue seeps out of the cracks.
Hold the pieces under the UV Lamp. Hold the pieces so that most of the rays shine through the glass and onto the glue. Do not hold the pieces so that the glass seam is directly under the light. Hold the piece under the lamp for the amount of time listed by the glue's manufacturer (approximately 5 minutes).
Scrape the excess glue carefully off of the seam with a razor blade.
Clean the piece with silicon-free glass cleaner when all of the pieces are glued back together.