Leaded or leadlight glass refers to a glass panel that is made up of several smaller pieces of glass held together by lengths of melted lead. The glass itself may be stained, and the lead holds together the pieces that then create a picture or pattern from the various colours. The glass may also be clear, and the lead may be shaped to create peaks or triangles for added visual interest in the glass panel.

Over time, the lead or putty under it may start to get damaged and leak onto the glass, causing a cloudy streak along those connections. Rather than assuming you can fix this yourself by replacing the lead and just cleaning the glass, note a few reasons why leadlight repairs should always be left in the hands of a professional.

Darkening the putty

The lead that holds the glass in position is actually cut in an H shape with a wedge in each side for the glass panes. The panes are held in place by a type of putty. Most leaded glass is cleaned with an oxidising agent, but this cleanser can react with the putty and actually darken it if left on the glass for too long. In turn, the putty can show along the edges of the lead. This discoloured putty can then make the glass still seem dirty and streaky; a professional will know the best cleanser to use, and how much, to keep the putty from discolouring.

Scraping the putty

When you clean leaking lead from glass, you may need to use a soft-bristled brush to remove streaks and discoloration from the glass without actually scraping the glass itself. However, even a soft brush can scrape the putty and pull some of it out from under the wedges in the lead. Not having enough putty under the lead can lead to loose glass that may eventually fall out of the pane, and also allow for water leaks through the window. A professional will know the best way to clean the glass without scraping the putty, and replace any dislodged putty to keep the glass in place.

Soldering

The edges of two lead pieces are actually soldered together to provide a secure frame for the window pieces. If you're not sure how to solder lead or another metal, this can lead to loose edges that aren't properly connected; as with a poor puttying job, this can also mean the risk of glass falling out and of water leaks. Let a professional handle the soldering to ensure the window sections are properly connected and secured together.