Aluminum Oxide Grit is probably one of the most versatile and widely used blasting media. Virgin Aluminum Oxide is refined from bauxite mineral ore. The blasting grit is about 95% pure with a hardenss of about 8.5 on the MOHS scale (diamond is rated a 10).
Due to the angular shape of Aluminum Oxide it exhibits excellent stripping and etching properties. This media is used to remove heavy oxidation, multiple layers of coatings and to produce at etched surface. Available grit sizes range from a very aggressive 12 mesh to a super fine 320 mesh. Finer sizes are available but are only used in specialty applications such as micro-blasting.
The hardness and aggressive nature of blasting with Aluminum Oxide makes it ideal for blasting hard surfaces such as steel or where surface etching and micro-finishing (often prior to coating or painting) is required.
Aluminum Oxide is a relatively expensive media but breaks down slowly. This combination would rate the overall operating cost as affordable. Aluminum Oxide is ideal for use in a blasting cabinet (versus a portable system) or a blast room where the maximum amount of media can be recovered and re-used.
White Aluminum Oxide is a more refined version (>99% purity) that has specialty applications such as dental, medical or electronic parts where purity surface contamination is of concern.