Directive: make a replica of the railing, manufactured originally with metal casting process. All decorative elements to be consulted with the local conservator.

The original balustrade corroded due to many years’ exposure to aggressive coastal weather.

At the customer's request, the balustrade was to be additionally coated with zinc. This requirement prevents joining the openwork elements by welding smaller fragments (please note the main element forming the balustrade body - a circle with star-like rods).

This element has been designed for cutting from a single sheet of metal with the laser cutting technology.

Why "welding the flat bars" wasn’t possible? It was due to the zinc coating requirement. The balustrade was to imitate the original without visible welds (not present in the original cast element). "Smooth" sanding of welded joints doesn’t help if the element is later hot dip galvanized. Joints will swell and will be visible after painting. This is due to the occurrence of internal stress after welding with a different silicon content in the weld and the parent material (elements that we weld together). Different silicon content is responsible for so-called Sandelin effect - the formation of an iron-zinc alloy on the surface of the element.

Another issue is the fact that manufacturing each element manually while maintaining adequate repeatability of the shape, would be very time consuming and generating much higher cost.

Fragment of balustrade after hot dip galvanizing.

Completed balustrade, after installation.

If you chose a hot dip galvanized and painted balustrade or fence, select a design in which the joints are part of the composition or simply do not impair the aesthetics, if they are visible. Keep in mind that some contractors (often under the pressure of the customer) smooth the joints by sanding them after galvanizing and before painting. Such action impairs the protective coating and causes corrosion to appear much sooner.

Photo credit: niessbernard on Visualhunt / CC BY

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