Cleaning of VM ZINC surfaces
Salt deposit should be removed by water, preferably by high pressure sweeping, so that the deposits are washed off from the panel surface. As higher temperature makes water more effective, water temperature can be 20°C - ca. 60°C , even up to 100°C. The water can be high pressure (< ca. 150 bar = under 2100 psi), but the water jet should have an angle of about 15° - 30° and should have an angle of impact of 30° - 60°. Start with a distance between the nozzle and sheet of approximately 20cm and find out how effective this is - the distance can be reduced to ca. 5 – 8 cm , but be aware that impact energy does increase by quadratic ratio. In case steaming is (locally) not strong enough, cleaning can be re-enforced by mechanical cleaning with soft mop. This should be limited to the affected area; otherwise you will find wiping marks on the surface. It is possible that the cleaning can not produce an absolutely uniform surface, but the task of the cleaning procedure is to remove the aggressive remains so that the natural passivation can become effective After cleaning, small dark spots will appear on the surface, which will diminish in the course of natural passivation. As soon the natural passivation layer has formed, the surface of the zinc-copper-titanium sheet is much less reactive, therefore future deposits will have much less aggressive impact onto the surface. Caution: High pressure water can enter the panel seams. Make sure that the water does not enter the building envelop. Salt deposits do not compromise the integrity of the material.
Umicore Australia Building Products – VM ZINC Unit 9 / 50 Stanley Street East Sydney NSW 2010
Tel: +61 (0)2 9358 6100 Fax: +61 (0)2 9358 1025 Email: vmzinc.australia@umicore.com www.vmzinc.com.au