MENDING A LEADED LIGHT
When you replace a pane of glass in a leaded light window, try if possible to leave the window in position: leaded lights are easily distorted when removed from their frames.
If the window has already bulged, remove it carefully and lay it on a flat surface. Once supported, you can gently press the lead sections (called cames) down flat.
1. To remove the broken glass, use a sharp knife or old chisel to cut carefully through the solder holding the joints at both sides of the bottom of the damaged pane. Now turn back the side and bottom cames with an old chisel, tap out the broken glass and dispose of it.
3. Scrape out any remaining putty from the cames, and clean them thoroughly with a stiff brush — a wire brush is ideal.
4. You must cut the new glass slightly smaller than the distance between the open cames. This can be done by cutting a piece of stiff card to fit and then using it as a pattern when you cut the glass or get your glass merchant to cut it for you.
Fill the cames with putty. Glass merchants may sell special putty for the purpose, but you can use metal casement putty instead of this.
5. Slot the glass into the unopened top came, then gently, press it into position round the sides and bottom. Any excess putty will ooze out of the Games as you do this.
6. Close the open side and bottom cames, pressing them flat against the glass with the back of a spoon. Trim off any excess putty with a putty knife.
7. Tap the broken joints back into position and burnish the lead around them with a medium grade glasspaper.
8. If you have a soldering iron, you can repair the joints with solder. Apply flux, then solder with a moderately hot iron, so as not to melt the lead. Finish by rubbing over the joint in a circular motion to smooth it.
If you cannot solder the joints, you can make a satisfactory repair with epoxy resin adhesive. Mix the adhesive, then stir in a little of any inert black colouring — such as soot — to disguise it. Apply a blob to the joint and smooth it over carefully.
Brush a little black oil paint, or plumbers’ black, into the putty so it will not show against the lead.
Once the window is back in position, check carefully for any leaks around the new pane the next time it rains.