Since the glass gasket is not subject to regular wear each time you operate your door like the door gasket is, your window gasket should last a very long time. However, if it ever needs replaced, this kit is what you need.
To install a new gasket, remove the four mounting tabs holding your glass in and lift out the glass pane. Thoroughly remove the old gasket and scrape off any old cement from the door surface. Then, dampen the area with water and apply a thin layer of cement to the gasket channel. Press the gasket firmly into the cement, being sure to keep the gasket material in a relaxed state, avoiding stretching it at the corners. Trim the gasket to length as needed, and use the included tape to secure the cut ends of the gasket.
Mount the glass back in your door to ensure a good seal, then allow to air dry for 1 hour. Fire the stove within 30 days and heat to 500 degrees F to cure the cement.