Selecting The Right Garnet Abrasive

Garnet has been used for decades as an abrasive in water jet cutting and sand blasting because of its superior physical properties. When added to high pressure streams of water, garnet abrasive is capable of cutting through tough materials including steel, aluminum, stone, and Inconel.

With the variety of garnet abrasives available, how do you decide which is right for you? By understanding a little more about garnet, you are able to make an informed purchase on which type of abrasive would work best for your application.

◆Water jets Abrasive

A water jet should be seen as an accelerated, controlled erosion process. A pure water waterjet (one without abrasives) is ideal for very soft materials, such as rubber, foam or food products. When abrasive is added, virtually anything can be cut or eroded away. By adding abrasive, you can greatly enhance the cutting capability of your waterjet and expand the variety of materials you can cut.

A waterjet will use anywhere from 0.3 lbs/min to 2.0 lbs/min of abrasive. This quantity is known as the abrasive ow rate and is determined by factors including the size of your pump and nozzle. The typical usage for a waterjet company is about one pound of abrasive per minute per cutting head.

◆Advantages of Garnet for Waterjet Cutting

Garnet is a hard mineral typically rated between 7.5 and 8.0 on the Mohs scale (where diamond is 10 and talcum powder is 1). Also, well washed garnet abrasive does not produce a lot of dust when cutting like other processes might. Garnet is also relatively chemically inert and will not react with materials being cut, making its disposal simpler. These qualities are advantageous in waterjet machining.

◆Types of Garnet Abrasive

Types of garnet abrasive are determined based on their origin. Today, the largest sources of garnet sand used for water jet abrasive are the Indian and Australian alluvial deposits, China hard rock. Understandably, the main producers of garnet abrasive are companies that are also located in Australia, China and India.

◆Alluvial garnet (river garnet)

Alluvial garnet is particularly abundant in Australia and India. This alluvial garnet is typically found in deposits in river bends or natural hollows and has been smoothed by constantly running water. Both river and the beach garnet suffer from the tumbling effect of thousands of years which rounds off the edges.

Generally speaking, rock garnet can be used for cutting hard materials with high efficient, and river garnet can keep the cutting surface more smooth. That's up to your final choice.