Illustration 262 Broken cast iron railings (Picture: Swailes)
Illustration 264 Forging of wrought iron glazing bars (Picture: Dorothea Restorations Ltd)
for different types of casting, including decorative work and, because the raw materials are better understood, modern grey cast iron is generally superior in terms of material strength to any made in the nineteenth century. Poor workmanship at the foundry can result in poor castings being made from superior materials and a good casting will be generally free from surface blowholes or scabs and require little 'fettling' prior to painting. If possible, the opportunity should be taken to examine castings at the foundry prior to their being painted. The ownership of patterns should be agreed at the outset between the client and the foundry as patterns are expensive and may retain a value once the work for which they were made has been completed.
Illustration 263 Welded repairs to wrought iron glazing bar ends (Picture: Heritage Engineering Ltd)
Occasionally, safety reasons may be cited as justification for the comprehensive replacement of original parts using superior modern materials. An example is the upgrading of the solid cast iron parapets at North Bridge Edinburgh, over Waverley Station. Here the panels were recast in spheroidal graphite (SG) cast iron, for greater ductility and to cover new steel vehicle restraints. For the ornate cast iron parapets to Cleveland Bridge in Bath a solution was found that