AFC Anodising & Finishing are able to offer a wide range of colour anodising. Anodising colour is affected by a number of different variables: alloy type and temper, load time, etch time, tank temperature and coating thickness.
We are able to control many of these variables our process. For best results it is advised that the customer supply a sample for testing.
The process takes place immediately after anodising when the anodic film is still fresh, uncontaminated and hygroscopic. At this point the piece is lowered into the colour where dye is encouraged to enter the pores, thus changing the film colour. All dyes are then sealed in Prefix and then the anodic film is sealed in a hot seal.
The most common anodising processes, for example sulfuric acid on aluminium, produce a porous surface which can accept dyes easily. The number of dye colors is almost endless; however, the colors produced tend to vary according to the base alloy. Though some may prefer lighter colors, in practice they may be difficult to produce on certain alloys such as high-silicon casting grades and 2000-series aluminium-copper alloys. Another concern is the "lightfastness" of organic dyestuffs some colors (reds and blues) are particularly prone to fading. Black dyes and gold produced by inorganic means (ferric ammonium oxalate) are more lightfast. Dyed anodising is prefixed and sealed to reduce or eliminate dye bleed out.
Splash effects are created by dying the unsealed porous surface in lighter colors and then splashing darker color dyes onto the surface. Aqueous and solvent based dye mixtures may also be alternately applied since the colored dyes will resist each other and leave spotted effects.