We were approached by a local company, Morart Design, to help in the restoration of a large cast iron stained glass window frame for St Michaels Church in Barbados.
The weathered and worn originals were shipped to our foundry in Kettering. We reassembled the complete window to determine the extent of the work we were required to undertake and establish which of the originals could be used to aid in the manufacture of the new components.
The necessary pattern work to allow manufacture to commence was completed. This ranged from making the originals longer, which allows for the fact that metal contracts as it cools, to also making new patterns for the components that were beyond repair. Without the contraction allowance the new castings would be too small for the window aperture.
The next stage of the process was to produce the moulds for the liquid metal to be poured into. This involved placing the patterns in a metal box and filling with silica sand coated with a resin, there are usually two halves to a mould. Once the sand had hardened the patterns were removed from the mould to produce the mould cavity. The mould was then hand finished removing any imperfections that could affect the finished product.
The metal was melted in our electric induction furnace to produce molten metal at a temperature of 1500 degrees Celsius. The molten metal was poured into the mould and allowed to solidify before the casting was separated from the sand.
Once the castings had been separated from the sand they were then subject to a finishing process which produced a flawless finished window frame. The sand from the used moulds can be reused to produce further moulds after undergoing a number of treatment processes.
Once all of the hand finishing work was complete the parts that required machining to allow the window mechanism to work correctly were then tackled. Due to the nature of the windows opening and closing operation some areas were inaccessible to our machine tools due to the tight constants of the apertures we had to work with. Several jigs and fixtures were designed and manufactured by ourselves to allow our machine tool fitters to accurately drill the required fixing and pivot holes.
The new castings were then packaged with the existing components and returned to Barbados.
The end result was a faithful recreation of a period piece that has exceeded the clientÂ’s expectations.