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Powder coating in “water test”

Fig. 1: Sheet metal samples at the hull of the Danube ferry
Fig. 1: Sheet metal samples at the hull of the Danube ferry  
Fig. 2: Danube ferry at Ottensheim
Fig. 2: Danube ferry at Ottensheim  

ENVIRAL® Austria

Bislang gelten Bauteile, die dauerhaft dem unmittelbaren Kontakt mit Wasser ausgesetzt sind, als „nicht pulverbeschichtbar“. Denn Pulverlack kann – mikroskopisch betrachtet – über winzige Poren in seiner So far components that are in permanent direct contact with water have been regarded as “non-powder-coatable”. Because microscopically speaking, powder-coating has tiny little pores in its surface and can absorb moisture including the chlorides it contains. These infiltrate the lacquer layer, which usually leads to its detachment from the coated surface and the formation of corrosion. We already reported on our “house-internal long-term study” in a previous edition (compare News-Reports 07/2010 and 04/2012).

However, the demand for powder-coating systems that would withstand the extreme conditions of maritime climates as well as permanent water contact has continuously grown lately. First and foremost, hydraulic engineers and boat constructors request high-quality coating solutions for their buildings and boats. Even the energy industry needs high-quality coating systems for their off-shore wind power plants in the North Sea and the Baltic Sea. ENVIRAL® has responded to this trend at its location in the Burgenland community of Pöttelsdorf. A long-term test has been in place since 08/09/2012 in which different coating systems are tested for their suitability in applications "under water".

To this end, sheet metal samples were finished with two different coating systems from different powder lacquer producers. One of them being a “classic” two-layer system consisting of a primer and a power lacquer finish. The other system selected consists of three power lacquer layers – primer, coating finish and clear varnish. These sheet metal samples were tightly mounted to the hull of the Danube ferry at Ottensheim, so that one part of the sheet metal would have permanent water contact (compare fig. 1). The results of a first examination of the coated surface after approximately 800 hours of permanent exposure in the river Danube were positive: all measured values showed excellent quality. Further examinations, measuring and documentation of the sheet metal samples will take place on a monthly basis.

The Danube ferry boat at Ottensheim at river kilometre 2,144.33 (compare fig. 2) operates daily from 6.15 am to 7.30 pm all year round. At the above-mentioned location and with normal water level readings of 300 – 400 cm, the Danube has a flow rate of 4 to 6 km/h. In case of high tide the level readings can rise up to 800 cm, increasing flow rates up to 25 km/h.

Kategória: ENVIRAL Austria

ENVIRAL ® Oberflächenveredelung GmbH – A-7023 Pöttelsdorf, Viktor-Kaplan-Allee 3 – Telefon +43 (0)2626 50074 – Telefax +43 (0)2626 50074-74 – 0800 400 150