Aluminum Oxide VS Zirconia

Aluminum Oxide VS Zirconia

If you are in the market for sandpaper, but you are unsure which grain you should use, this article will help you pick between the two most common materials. The two most popular grains of sandpaper are Aluminum Oxide and Zirconia; however, there is also ceramic and silicon carbide. It is important to know the difference between the two so you can get the finish you want and avoid damaging your project. 


Abrasive grain is solid and when used with pressure, it will shave down and lessen the surface you are working on. You can purchase these in sanding discs, sanding belts, or sanding sheets and they can be used on different surfaces like softwood, hardwood, metals, glass, etc. Along with picking which product to use, you must also consider what grit to use. For example, wood does not need that harsh of a grit compared to a metal. 


Now let’s talk about Aluminum Oxide and what it is. Aluminum Oxide is in fact the most popular grain. It comes from a sedimentary rock called bauxite. Bauxite contains high levels of aluminum. It is boiled at a very high heat in order for it to become an abrasive grain. Iron borings and coal that is low Sulphur is put into the melted bauxite and it is then melted even more at a higher temperature. Aluminum Oxide is low in iron so it helps to prevent rusting – helpful for when you are working on metals. Aluminum Oxide tends to be a brown color, affordable, and reliable. You can use this grain on drywall, removing dry paint or lacquer, smoothing a surface, and much more. There are four different categories of aluminum oxide; friable, semi-friable, heavy duty, and regular. The difference between friable and heavy duty is that friable is soft or fine and heavy duty is more dense. Brown aluminum oxide is semi-friable and is great for cutting more material fast while remaining cool so there is no burning. If you have a bigger project to work on, such as a floor, it is recommended to use a heavy duty or regular aluminum oxide. Staying on the topic of big projects, something that can be very handy to you is a sanding belt. You can purchase common belt sizes, but also manufacturers can make special belt sizes that best suit your projects and sanding tools! 


Zirconia is more solid than aluminum oxide and its lifespan is usually longer – although it is more expensive. Zirconia is more coarse and it is a crystallized version of aluminum oxide. It comes in a green or blue color and it is great for harsher materials that you are working on. It also self-sharpens which means you can use it for longer rather than switching out discs or belts often. If you are working on a more coarse surface, zirconia could be a good choice because it can save you some time. Zirconia is best for metals and high pressure jobs that require a lot of heat. While you can use aluminum oxide for wet or dry sanding, it is best to use zirconia for wet sanding. You can also purchase zirconia belts if you are working on a large surface. However, as great as zirconia is at cutting harsh material, it is not recommended for polishing a surface because of its density. 


To sum it all up, if you are working on a project that is smaller wood/metal, softwood, painted wood, and are on a budget or need sandpaper fast – you will have an easier time finding and using aluminum oxide. If you need something with life longevity, heavy duty/coarse materials, bigger surface areas, or wet sanding , zirconia is going to benefit you a lot.

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