Water, though considered one of the most essential things for human survival,may also have detrimental effects. Rusting of the metal, weakening of the giant metallic structures is all because of the water. Therefore, protecting the metal substrates from water is very important. Coating the metallic substrates not only adds aesthetic value to it but also protects it against rust.
Majorly, MS and SS are used in Vigyan Ashram. The major difference between these two is that the composition.MS is Mild steel also known as carbon steel is an alloy of iron and carbon and is usually soft, ductile, cheap and easy to work with compared to them later. SS stands for Stainless Steel is an alloy of iron and carbon (steel) with a minimum of 11% Chromium and SS can be soft or hard depending on the carbon content and heat treatment. Chromium in the SS imparts anti-corrosive properties to the SS and makes it superior to MS. But, during cutting and grinding it is observed that the chromium oxide layer of the SS gets destroyed and hence can be a cause for rusting.
Surface treatment before coating or painting the metal body becomes an essential thing. Surface treatment includes cleaning, filing, grinding, pickling, grease removal and lastly primer coating.
Cleaning with sandpaper will ensure that dirt is removed and will also help to check for unlevelled surfaces. Use of a pickling agent ensures the rusted surface is removed and also removes earlier paint or other coating stains. Pickling agents generally consist of strong acids. The below pic shows before and after effects of pickling agent. Here, 25% sulfuric acid solution is employed as a pickling agent. The wire mesh is soaked for up to 10 mins and then washed with water.
Surface treatment of the RTLD.