Things You'll Need
Stained glass window
Paper towel (lint-free)
1/2 inch wood spacer
Techniques for installing stained glass windows vary depending on the existing window setup. A stained glass window is usually installed against an existing window, which provides protection and support for the stained glass. Either silicone or wood trim are used to hold the stained glass in place. According to Kessler Studios, stained glass windows should not exceed 14 linear perimeter feet in total size. Windows larger than this may require custom framing to hold stained glass panels up to this size.
Clean the existing window and both sides of the stained glass.
Hold the stained glass window in place to make sure it fits correctly. There should be about 1/8-inch gap between the frame and all sides of the stained glass. Place a few pieces of masking tape from the frame to the stained glass to hold it in place.
Cut little pieces of cardboard, about 1/4 inch wide, and put them around the stained glass as spacers against the window frame.
Squeeze the silicone carefully into place around the edge of the stained glass. Use the toilet paper to clean off any stray smudges of silicone. Smooth the silicone into place with a finger if necessary. Caulk up to the cardboard but not on it, so it does not stick in place. The cardboard will be removed when the caulk is dry to provide vents, preventing condensation buildup between the windows.
Fold a piece of cardboard into an accordion shape, as described by David Gomm of Better Stained Glass, and secure it into place against the window with a strip of masking tape stretched from one frame to the other. Place a couple pieces of masking tape on either end of the long piece to help hold it in place.
Allow the silicone to dry at least 24 hours, then remove the small cardboard strips, the masking tape and cardboard accordion.
Wood trim installation
Clean the existing window and both sides of the stained glass panel.
Measure and cut the 1/2-inch wood spacer and install it on the wood frame against the existing window glass.
Measure and cut the wood trim.
Set the stained glass window into place against the spacer.
Secure the wood trim in place against the stained glass with small nails.