What is rust?
Rust is the kryptonite of steel. Tiny molecules (either acid or oxygen in combination with water) break down the steel electron by electron until there is nothing left. Molecules like oxygen are very reactive, meaning they either give up or take up electrons from other atoms. In this case, they steal electrons from the steel atoms, which are then unable to maintain the connection to their neighbors. In this case, the surface dissolves over time, becomes porous and cracks.
How to prevent rust?
One way to prevent rust is to use stainless steel. If this is not possible, the steel surface must be sealed so that acids or water cannot come into contact with it. For this purpose, there are many oil- or water-based one- or two-component coatings such as Power Coat 3 in 1 or MonoGuard. Anti-corrosion paints have the ability to penetrate the surface, which gives them very good adhesion and sealing. It is also important that the coating has very good edge coverage, so that even weak points are sufficiently protected.
Before you paint…
If the surface is not well prepared, the coating cannot do its job and the steel will rust over time.
- It is important that the surface is free of loose rust and dirt – this should be obvious as the paint will then not be able to adhere to the substrate and will start to peel off after a short time.
- The surface must also be free of silicones, oils and grease, as these have just as good penetration properties as paint and thus seal the surface and prevent the paint from adhering.
- The surface must not be too smooth. They are difficult to paint, for example glass. The paint needs small pores in the surface that it can flow into and anchor. Therefore, smooth surfaces should be sanded to make them rough. Alternatively, special primer can be used.
- The surface must be dry. We don't want to trap moisture that will condense, blister and loosen the paint.
- It is usually fine to paint over previously painted surfaces. It is important that the old paint is still firmly attached. Where it is loose, it must be sanded down. Check that the old and new paint are compatible. Similar works well. For everything else, check the product's technical data sheet or contact the manufacturer. For large projects it is not worth taking the risk.
