Ballantine Castings have been lucky enough to play a part in modern construction projects that seek to retain the cast iron designs of Britain’s past and merge them with the most up to date structural and architectural techniques. Over the years we have taken on many projects outside of our normal remit (see our case studies for more examples). Our flexibility in terms of in house services and expert knowledge mean that we can take on almost any commission that is brought to us. But every now and again a truly complex and invariably interesting job comes to the foundry. It’s not every day you get asked to make 450 cast iron paving slabs.
Working in conjunction with Gillespies Landscape Architects and McAleer and Rushe, Ballantine Castings won a supply contract for over 450 number, 500mm square, architectural and structural paving slabs and drainage gratings for a new development in the heart of Edinburgh.
There were three variations of ornate, paving slabs with a slight variation on the design to allow for drainage units and tree grilles. The contract was made intricately complex due to the design of the gratings and the loading requirements of the drainage units. Each unit had to meet perfectly on each face to ensure the continuation of the design throughout the layout whereas the drainage units had to adhere to D400 loading requirements to allow for the access of emergency vehicles.
Ballantine Castings technical drawing office provided CAD drawings and 3D modelling to be signed off by the architects prior to production taking into account the design and structural requirements of the paving units. Following this our pattern shop created 3 individual patterns to the designs ready for production. The drainage units were then tested by our sub-contracted ACAS approved laboratory to prove the design could meet the D400 requirement. Thanks to our expertise in casting design and production the grilles passed the loading requirements first time.
Production was done at a rate of 50 units per day in our specifically designed airset plant with castings made both in ductile iron GR420/12 and in GR250 cast iron (to see our metallurgical range please follow this link). Due to the set up of the units every outside face had to be machined in house to leave a 1mm gap between the units on all faces. Once machined, all castings were checked by our quality department, to ensure the aesthetic and structural integrity of the units. Every single casting was checked for hardness, underwent spectrographic metallurgical analysis, non-destructive and destructive testing, prior to being signed off for dispatch. Each unit was then drilled and tapped with countersunk holes to allow for tamper/vandal poof fixings into steel stringers laid out in the concrete foundations.
The final results speak for themselves as the paving slabs will look magnificent in what is already an excellent construction development for the cit of Edinburgh. Cast iron is often overlooked in modern architecture in favour of cheaper and more fashionable alternatives or, indeed, foreign imports. But these units not only look incredible but will also last for generations to come – cast iron is as much a part of our architectural heritage as it is our future. And we at Ballantine Castings are proud to be at the forefront of the industry; providing aesthetically stunning and structurally compliant castings to clients throughout the UK and abroad. Please get in touch if you have any enquiries about this, or indeed, any other of our cast iron projects.