Dry Ice Blasting: The Recognised Method for Graffiti Removal from Corten Steel
Dry ice Blasting has long been considered third choice behind water and grit blasters when it comes to removing graffiti from surfaces. This is mainly due to costs and we accept that we cant compete on this particular playing field.
Weathered Steel (or Corten Steel) is one surface, however, where dry ice blasting has become a viable option for removal of graffiti, and after carrying out recent trials, Optimum now has a full understanding as to why.
The idea of weathered steel is to save massive costs in the upkeep of structures whilst still offering an aesthetically pleasing design. The copper colouring of the surface patina gives a rich glow to structures and architects, the world over, use it.
The big problem arises when having to clean graffiti from the steel. Most traditional methods (sand, grit blasting or chemical removal) actually destroy the patina, taking the light rust away and exposing the smooth steel underneath. The patina can’t ‘grow’ back in these places and so a non-uniform, blotchy appearance occurs.
The Solution
Dry Ice Blasting, however, is the viable solution. The non-destructive effect of the cryogenic (kinetic) impact, means that the paint/contaminant can be removed without destroying the patina and thus maintaining the uniform appearance throughout the surface/structure.
It is so successful that a white paper has been written on the process and was commissioned when a graffiti removal programme had to be implemented on Chicago’s iconic Time Life Building. The paper can be read here.
Our own tests also proved to be a great success and a full report can be requested by contacting Optimum directly and a short video of the trial can be seen here – https://www.youtube.com/watch?v=Sa2hYdMZiAI
We would like to thank Make Architects for their write up of the process (which you can read here) and Severfield Watson Structures Ltd for their input and participation in this trial.
By Ian Reynolds