Rather than throw away or spend money on repairs for your broken or damaged stained glass lamp shades, you can follow the simple steps below to try to fix it.
Step 1 - Getting Ready
Remove the stained glass lamp shade from the lamp base and situate it on a flat surface. Make a rubbing of the soldered seams surrounding the broken glass with paper and pencil or any other marking materials.
Step 2 - Breaking Up Glass
Use a glass cutter to score a cross-hatch pattern on the glass. Use pliers to break and remove shards. When doing this, pull out and away from the lamp so as not to place additional strain on the surrounding pieces of glass, leaving the working area clean. Obtain a cardboard box bigger than the lamp shade and block it up with wadded newspaper. Rest the shade in this box, using the newspaper to prop the lamp so that you can solder on your work surface.
Step 3 - Soldering a Glass
Apply liquid or paste fluxes on the solder bead adjacent to the broken glass. Heat the solder with your soldering iron. At the same time, use the tip of the iron to do away with excess solder from the seams on both sides of the broken pane. Be vigilant to run off the foil on the surrounding pieces of glass intact. At the same time, use needle-nose pliers to pull away smashed or broken foil.
Step 4 - Patterning the Glass
Incise out the rubbing of the broken or smashed glass section and mark out it onto new glass with permanent or stable marker. Incise out the glass and grind to fit the area. Check to make sure it fits before foiling. Bring into play copper foil to enfold the edges of the new piece of glass.
Step 5 - Applying the Glass on the Broken Part
Change the foil on the new piece of glass as well as the foil on the pieces of glass adjoining the missing piece. Tin the new piece of glass by soldering a thin coat of solder over the foil. Reapply flux to the solder on the new piece and place it into the new spot. Use electrical tape on the inside of the lamp to hold the glass in place. Path solders the glass into place by soldering small amounts of solder at several spots where the new piece touches the surrounding pieces.
Using your soldering iron, melt and apply solder to the front seams of the entire piece of new glass and the surrounding pieces. Once the front is complete, remove the electrical tape and flux and solder the inside.
Step 6 - Finishing Touches
Once the soldering is complete, use dish soap or soap designed for removing flux to clean the lamp shade. If a patina was used on the rest of the stained glass lamp shade, use the same kind on the new section so that it will match. Follow up with an application of glass wax to the entire piece.