Aluminum wheel manufacturing involves several investments: acquiring bulk material, casting/forging, machining, polishing and painting. The painting process inevitably produces paint rejects which are normally reclaimed by various paint stripping methods, each with its own unique set of advantages and disadvantages. This paper contrasts four commercially available paint stripping methods and their impacts on health, environment and safety (HES), aluminum material properties and the performance of a repainted wheel.
The comprehensive study compares the effects of the four most common commercially available paint stripping methods - a low boiling point solvent, an acid stripper, an inorganic process at high temperature and an organic fluid. HES and safety aspects are reviewed (worker health and safety, local regulations and waste disposal). Aluminum material properties after each paint stripping method were measured: grain structure (x-ray diffraction and optical microscopy), surface appearance (field emission scanning electron microscope and optical microscopy), elemental mapping (energy dispersive x-ray spectroscopy), surface roughness (profilometry, confocal microscopy and atomic force microscopy), surface hardness and Young's Modulus (nanoindentation), and surface reflectivity (qualitative visual inspection). Paint performance after repainting is evaluated by adhesion and filiform corrosion.
After considering HES, material properties and performance, one preferred technology emerges for reclaiming aluminum wheels with paint defects.