How to Make a Leaded Panel

Staircase Window with Purple Tulips

Leaded panels are held together by came, strips of lead with an H-shaped cross section. The groove on each side grips the edge of a piece of glass, and the soft metal can be bent around curves. Joints are soldered, and the panel is sealed with cement. The method has changed little for several centuries, and it is how most traditional windows are made.

Tools and materials

  • Lead came: the H section for internal lines and a U-shaped or wider section for the outer border. Common internal widths are about 3/16 inch (5 mm) and 1/4 inch (6 mm).
  • Lead knife or nippers, and a stretcher or vice (see how to cut lead came)
  • Lathekin or fid
  • Work board, four straight wooden battens, horseshoe nails, nails and a hammer
  • Set square and a full-size pattern, called a cartoon
  • Flux, solder and an iron
  • Glazing cement, whiting and brushes

Method

  1. Stretch the came. New lead is soft and slightly kinked. Grip one end in the vice and pull on the other with short, firm tugs until the metal stops giving. This straightens it and makes it stiffer.
  2. Open the channels. Run the pointed end of the lathekin along each groove so the glass can slide in easily.
  3. Set up the board. Fix the cartoon flat to the board and nail the first two battens square against the pattern, leaving room for the border came.
  4. Cut the glass. Pieces are cut to the cartoon, allowing a little room for the lead heart, the thin central web of the came. Cutting accuracy matters here.
  5. Start in a corner. Cut the first lengths of border came to the right angle and bed in the first pieces of glass.
  6. Build the panel. Add glass and came working outwards diagonally from the corner. Cut each length of came a little short of the glass to allow for the flange where it meets another came. Hold the work in position with horseshoe nails set into small scraps of lead.
  7. Check the size. Measure the panel against the cartoon repeatedly. If it grows, find the cause before going on. It is usually the came rather than the glass that has crept.
  8. Close the panel. Cut and fit the final border lengths and add the last two battens. Check that the corners are square.
  9. Solder the joints. Flux and solder every junction on the face, using a quick touch of the iron so the lead does not melt. Turn the panel over and solder the back.
  10. Cement the panel. Work a thin mix of glazing cement under the flanges of the came with a stiff brush so that the glass is held firmly and the panel is weathertight. Clean away the surplus with whiting, a fine powder, and polish the lead.

Glass thickness and the size of came

The channel of the came has to suit the glass. Standard came with a heart of about 5 mm is made for glass of about 3 mm, and the extra depth holds the cement. Thicker glass, such as 4 mm patterned glass, needs came with a deeper channel, and suppliers list high heart came, with a heart of about 7 mm, for this. If the channel is too shallow the glass will not sit properly, the flanges will not close down on it and the panel will be loose. Test a piece of the glass in a short length of the came before cutting the whole job.

Design notes

Where possible, leads should meet at junctions rather than running straight through, because a long straight lead is a natural place for a panel to flex. Long, narrow tapered pieces are also hard to lead neatly. Large panels in windows are supported by saddle bars, with copper or lead ties soldered to the back of the came and wrapped round the bars. Fitting into a frame is traditionally done with putty.

Cement

Traditional glazing cement is a mix of linseed oil, whiting, lamp black and a solvent such as white spirit. It is worked under the lead on both faces and then left to harden, and whiting is brushed over it to absorb surplus oil. Surplus cement should be cleaned off the glass before it hardens.

In this section

Terms used here are explained in the Glass Glossary, and the Learn section covers the history and types of glass.

See also How Lead Came and Overlay Lead Are Made.