Architectural Leadlights
Offaly, Ireland
Condition
The two leadlight casements are from the entrance doors of an estate house in Ireland dating to c.1810.
The frame is constructed from a tin plated ferrous metal and sand-cast lead all jointed by soldering. It was putty glazed with a mixture of historic and contemporary glass types from repeated repair. The frame was heavily corroded in areas causing serious structural instability which resulted in fractures to the joints, putty and glass. Areas of decorative lead were missing and were infilled with poorly executed putty repairs. The casements were heavily and untidily over-painted obscuring decorative details.
Treatment Aim
To stabilise, repair and restore the leadlights to provide weathertight structurally sound casements for reinstallation in their original entrance doors.
Treatment
Paint removal
Paint samples were taken from strategic locations on the frames for later architectural paint research. Excess paint and putty obscuring the decorative lead was softened with a UV heatgun before mechanical removal with hand tools and a stiff fibre brush to avoid damage to the soft lead surface. The historic glass was insulated during UV heat treatment to reduce likelihood of cracking.
Metal Repair
Corrosion to the ferrous frame and lead were identified and removed mechanically by brushing back with steel, glass and brass bristle brushes. Following corrosion removal, the ferrous frame was coated with one application of a microcrystalline wax to prevent atmospheric corrosion during further works. Where corrosion had resulted in disintegration of the ferrous frame replacement sections were fabricated to size using low carbon rolled steel and were joined by soldering with a lead-tin solder and a water-based zinc chloride flux. Soldering was chosen for jointing as it was the original technique used for these frames as well as being more reversible than welding. Cracked joints and missing solder blocks were also mechanically and chemically cleaned back and re-soldered.
Mould and Casting
Negative moulds of heat resistant silicone were made to match areas of loss using sections of the uncovered decorative lead to provide the form. Casts were made in lead, trimmed by hand to fit into the areas of loss and soldered into place.
Glazing
Damaged and loose putty and glass was removed mechanically. Panes adjacent to areas in need of metal repair were also removed to avoid damage.
Following completion of metal repairs, new cylinder glass was cut to fit missing panes and were bedded and reglazed in putty.
Aftercare
The casements were packaged for storage and transport and returned to site for installation. A detailed report documenting the history of the object, its construction, condition, treatment and aftercare was compiled for the client for their personal interest and to satisfy state funding requirements.
