Architectural and Ornamental Metalwork
Due to our great industrial past, many of our buildings and parks have fascinating period cast iron and wrought iron features that still exist in the form of gates, railings staircases and other details that imbue buildings with a distinctive character and quality synonymous with historical periods. Many buildings have wrought iron gates and door hinges, which have the individual character of the blacksmith’s forge. These buildings may also have brass and bronze fittings such as door knockers and other novelty metalwork, which have survived the changing trends through time.
The modern trend is to paint ironwork black but through inspection and even paint sequence analysis can reveal the original colour and coating system, which may even have incorporated gilding. This is not only historically interesting but may be useful to the custodian, owner or local council upon deciding a colour scheme following restoration. The original colour scheme may be adopted as part of a more generalised conservation programme.
The ability to cast iron has meant that it can be made into ornamental shapes and forms through the process of sand casting. Cast iron is brittle compared with wrought iron and missing pieces is common. The missing pieces can often be made by making a mould of identical parts. A pattern is then made and new pieces are cast by the same traditional process.
Cast iron cannot be joined by welding easily and is usually bolted together during assembly. The fixings and joins are then caulked, originally using white lead. Once this caulking fails the fixings will begin to corrode and water can enter the internal parts of the castings. Paint films and caulking need to be replaced once they have failed to prevent further catastrophic failure and corrosion jacking. If in poor condition it may be necessary to remove the paint completely from the cast iron, have the corrosion treated and then recoated in a high-performance paint system.
Wrought iron is less corrosive but is often in poor condition when regular and appropriate maintenance is not carried out. Previous corrosion followed by poor repairs sometimes means that sections have to be completely removed and replaced with modern steel. This modern steel may be functional but has none of the ornamental artistry and qualities that existed in the original wrought iron. However, it is possible to sympathetically repair wrought iron and replace missing items in the traditional manner and save the entire assembly from being lost.