Problem Solving Forum
November 22 - November 28, 2010
What would be an optimal coating system, in terms of both durability and productivity in field painting, for exposed structural steel on the exterior of a stadium built on the seacoast in a damp, cold environment?
Adam Backhaut of Volkswagen Group of America on
November 22, 2010:
Epoxy coating systems are quite durable and offer ...read more Epoxy coating systems are quite durable and offer excellent adhesion and corrosion resistance. I would recommend an epoxy zinc-rich primer with a high quality exterior polyurethane topcoat; this combo will offer excellent durability and weatherbilty. Make sure both coatings have adequate film build as recommended by the manufacturer of the coatings tech. data sheet.
Simon Hope of Bilfinger Salamis on
November 22, 2010:
First choice would be to power wash, dry and then ...read more First choice would be to power wash, dry and then abrasive blast to first quality (Sa2 1/2) and then apply 8 mils of thermal spray aluminium (TSA) sealed with a polyurethane finish coat whilst TSA is still warm and definately before the surface is exposed to the environment for any significant time. This will give the longest life performance but may not be practical for a variety of reasons though it is worth arguing the point against objections! If it is only possible to undertake minimal preparation, the most important thing to remember in coastal situations is removal of salts, this can only be achieved by fresh water washing and should be done before and after mechanical preparation and the surface assessed for residual salts before any coatings are applied. The ultimate performance on mechanical preparation tends to be using thick film aluminium/glass flake pigmented epoxy mastic with a high loading of Zinc Phosphate, a coat of Polyurethane finish gives cosmetic acceptability for colour stability and UV resistance. These typically work extremely well in the UK North Sea scenarios with some of the harshest exposures that coatings have to be applied and operate in so will be well within their comfort zone in this application!!