By Tony Grammauro
VP/ General Manager, Wheelabrator Impact Finishers UK
While our day-to-day work here at Impact Finishers revolves around the peening of aerospace and high-end automotive parts, we occasionally get involved in spectacular architectural projects – like the new Giant’s Causeway visitor centre, parts of the new Paddington Station or the famous Paternoster Vents by Heatherwick Studio.
Shot peening in architecture (and art!) is used for stainless steel elements that have to be aesthetically stunning, yet durable.
The peening process creates a subtle lustre on the steel, while protecting the surface against pitting corrosion and damage. It becomes scratch and vandalism resistant, glare-free and maintenance-friendly – without having to apply any coating to the surface. All this makes it attractive to architects who work on high-spec projects in the public realm or other high-footfall areas.
However, shot peening is a fairly expensive treatment and the cost benefits are long-term. Which is why architects sometimes find their specification challenged by contractors or by clients who question the need for this high-spec surface finish.
We frequently help architects tighten up their specifications, to ensure contractors don’t get tempted to look for seemingly equivalent alternatives, the deficiencies of which might only show a couple of years down the line. For the architect, this could stand in the way of delivering on their promise to their client – particularly when it comes to longer-term building qualities such as sustainability and future maintenance cost.
So, architects of the world, to help you stand your ground, here are a couple of things to look out for, when specifying shot peening and finding a contractor:
– if absolute long-term corrosion-resistance is required, a high-spec ceramic process might be needed – ferrous abrasive will not achieve the same result and is not a valid short cut
– for large, decorative areas, an automated process is needed to achieve an even and consistent finish without patches or streaks
– similarly, for precision shading of the surface colour (for example for low reflectivity) strict process control is important
The killer argument for customers, especially in the public sector, is that a surface shot peened to the standard specified will outlive its makers by some time – and will require little more than the occasional wash-down with soap and water to stay beautiful.