Ideally iron that is set in masonry should be packed in lead to create a water barrier. Sheet metal patches and welding are methods of repair to be used judiciously. Replacement of castelements can be done by a cast reconstruction, using metal or synthetic resins, or a wooden replacement. The foundry casting techniques are briefly described. Wood replacements are not to be spliced onto existing iron, because expansion/contraction coefficients are too different. -- AATA