Surface Preparation and Coating in Marine Vessels

Surface preparation and coatings for marine vessels, which inevitably contact water, differ from standard applications due to corrosion risk. Corrosion control is one of the most sensitive and technically demanding issues of our time, and planning must account for operational efficiency and the impact of surface treatment quality on overall quality, based on detailed analysis. This plan must comply with occupational health and safety standards and relevant environmental legislation. Several methods exist for corrosion prevention. In marine vessel construction, particularly in shipyards, coating (painting) leads the list of corrosion prevention systems. Painting consists of two stages. The first stage is surface preparation. Surface preparation comprises several steps within itself. The initial step is preparation for blasting, which involves removing weld spatter from the main surface or weld areas, or grinding surfaces that blasting cannot reach. Once this operation is completed, blasting can proceed.

Blasting creates profile depths on the metal surface. These depths vary according to the technical properties of the paint.

After creating surface roughness depths (in micron range) according to the paint specifications, all blasted parts or blocks are cleaned of grit both through pneumatic systems—using suction—and by air removal of fine dust from the relevant part. Marine vessel construction methods vary, and within each vessel, coating characteristics and desired surface standards also vary according to corrosion resistance or risk. Modern technology offers environmentally friendly and alternative approaches in surface preparation and painting technologies. In Tuzla and Yalova regions, the heart of Turkish shipbuilding, blasting and painting technologies are of major importance. For surface preparation in blasting and painting halls, automatic blasting chambers are typically preferred. On slipways or shiplift systems, blasting silos are preferred. These machines are used in new marine vessel construction. In repairs, marine vessels arriving at repair facilities or shipyards also undergo surface preparation using blasting silos or water jets. Most of these applications require significant amounts of compressed air, which advanced shipyards have as infrastructure. Automatic systems in blasting and painting halls collect the granules sprayed with compressed air, minimizing granule loss. After all this preparation, coating can proceed. Before coating, dehumidification machines are used in enclosed areas to prevent the blasted surface from darkening. During coating, air conditioning and filtration are of vital importance. In halls without adequate filtration, there is a risk of solvent explosion.

Fans used during painting should preferably have explosion-proof characteristics. Alfatechnic has selected all fans with explosion-proof specifications in all blasting and painting halls it has constructed.

After the first coat of paint, applying intermediate and final coats, reducing inter-coat and touch-dry times, is achieved through professional air conditioning and building structure design. This professional design and turnkey construction is carried out by Alfatechnic. Our facilities are designed in accordance with conditions stipulated by the Ministry of Environment. Shipyard regions, particularly in Tuzla and Yalova, being located close to residential areas, prompt us to place even greater emphasis on environmental health and safety issues. The dust collection systems and paint extraction filtration systems in our Alfatechnic Blasting Facilities emit to the environment at the rate stipulated by the Ministry of Environment. As Alfatech & Alfatechnic, our main line of business is provision of all enclosed blasting and painting halls, and all surface treatment equipment required on slipways. Particularly in marine vessel surface treatment technology, different types of manufacturing such as luxury yachts, ships, and fishing vessels have different solutions. Our general working practice is project design according to required needs, supply of equipment and machinery, and provision of after-sales service. For shipyards without space constraints, implementing surface treatment techniques in enclosed areas is highly important. It is a permanent solution. As Alfatechnic, we construct blasting facilities in national and international shipyards. Alfatechnic facilities are high-efficiency mega blasting and painting chambers designed to European standards with minimized operating costs, capable of operating 10-12 blasting nozzles and 8-10 paint pumps simultaneously.   Tolga Zent Sales Coordinator Alfatechnic Makina San. ve Dış Tic. Ltd. Şti.