How to Choose A Sandblast Media
Choosing the right sandblast media is important. Sandblast media is the one of three primary factors to determining the results of a sandblast operation. The first factor is operator technique, the second equipment type (suction or pressure fed blasting), and finally the media type. Knowing that media is so important to blasting it is important to consider the following when selecting a blast media for your work.
Media Hardness (Mohs scale)- This is a term that refers to how hard a media is and determines the cutting ability of a media. The scale is a 1 – 10 scale where 10 is the highest and 1 is the lowest. If you want to get more work done in a shorter time or a deeper profile a harder media is better however if you are trying to not alter the surface profile a lighter mohs is desired.
Media friability – This is a term that refers to how easily a media alters shape during blasting. The more friable a media the less reuse you will get out of a media. More reuses allow for better cost savings but sometimes it will take longer with a high reusable media to obtain a deep surface cut.
Media shape – Media can be angular, spherical, or natural. Different surface shapes have a greater or lesser ability to cut a surface. Angular offer the best cutting ability but generally at the sacrifice of reusability. Spherical are typically not well suited for cleaning but can be a great use when wanting to structurally strengthen a part ( a process known as shot peening). Natural shapes are those that are minimally altered prior to being used for blasting.
Media size – larger grits will yield a deeper and faster cut. However, they can also lead to overly removing surface material. Smaller media can be time consuming but will less likely result in over blasting.
By considering blast media’s shape, size, friability, and hardness you can best know how to improve your production or save money, whichever your goals are. You also want to collect each bit of this information so that you know how long you will be able to use a media, how much surface it will remove at a time, how quickly it will remove that surface, and will it alter the surface.
For a chart summarizing the types of abrasive media please visit here. Chart is from Metal Finishing, see reference below.
Hansel, Dave. “Abrasive Blasting Systems.” Metal Finishing. Vol. 97. Tarrytown: Metal Finishing,
1999. 29-55. Print. Ser. 14.