What, Why, How – Bright Polished (Ultra™ Marine) Stainless Steel
Posted on 16th March 2023
Why does Bright Polish reduce corrosion opportunities? Especially in highly corrosive environments like marine and swimming pools?
Bright polish is a high lustre polish process for certain metals which involves gradually polishing an item with different grits of abrasive belts and high speed buffing wheels and compounds to achieve a mirror like finish.
The Science – Simplified
When you look at the surface of stainless steel through a microscope it will consist of peaks and troughs which are the result of the abrasive scratching the surface. This is called surface roughness and is measured using a Ra (Roughness average) value, measured in microns.
The surface roughness (depths of the scratching or grain) is what determines the different aesthetics typically either giving a dull or bright finish.
Bright Vs. Brushed (Satin)
Dull finish is more of a matt or sometimes referred to as brushed or satin finish. This has a deeper grain and often classed as a more contemporary architectural finish.
Bright finish is a highly polished version sometimes referred to as mirror polished. This has a very very shallow grain.
If stainless steel ever appears to ‘rust’ it is not actually the steel itself but contaminants from the environment that has damaged the passive layer and collected in the groves.
Hence the reason why a bright polish is the most corrosion resistant. With less opportunity for contaminants to settle in the grain and when they do, they quickly get washed off the shiny surface.