Profile: London Colney Anodising Co. Ltd specializes in the surface treatment of aluminium and its alloys. Sulphuric acid anodising is the most commonly used. It can produce a transparent film of optimum corrosion resistance. The film thickness would vary depending on the application, from between 3 & 25 microns. Finishes include alkali etching, chemical brightening, mechanical polishing & graining and sandblasting services.