How it’s made
Making traditional stained glass windows is a slow process.
However, the final result is proven to last for centuries.
The layout
The stained glass window starts with a sketch or cartoon. Clear or colored glass pieces are cut to fit each piece.
Painting
Details are added by painting. This paint is a glass powder with a little water and binder. The traditional paint is only opaque black or brown to block the light. It can be added or subtracted from the surface of the glass to block the light or make shading.
Firing
Once the glass dust is all in place, don’t sneeze. Water drops can ruin the work and a wet rag can wipe everything away. The pieces are fired in a kiln to 1250 degrees F and the powdered glass fuses to the surface of the glass sheet.
Silver Stain
In the 14th century crusaders learned how to change the color of glass using silver oxide.
This allowed a clear piece of glass to include yellow highlights without having to cut a separate piece of yellow glass. Now a king’s crown or a saint’s halo could be a range of yellow or gold tones by applying silver oxide and firing in the kiln again. This became so popular and widespread that we still call the entire art form “stained glass.” This is not because of the colored or painted glass that had already been used for centuries. Staining is the permanent yellowing applied to another sheet of glass.
Assembly
Once all the kiln work is done, the pieces are assembled by soldering. Lead bars with an “H” cross section are fit between each piece of glass. For watertightness, special cement or putty is then worked into every joint.
