To begin to compare grit blasting and shot peening, it’s important to understand the difference between the two. What exactly is the lesser known shot peening? Shot peening is a cold working process, impacting a surface with shot (round metallic, glass, or ceramic particles) with enough force sufficient to create plastic deformation.

For machinery, shot peening is used to strengthen and relieve stress in components like connecting rods. For architecture, it provides a muted finish to metal. Peening a surface spreads it plastically, causing changes in the properties of the surface. Shot peening is often called for in aircraft repairs to relieve stress built up in the grinding process, replacing them with beneficial compressive stresses.

Shot peening is similar to grit blasting, except that it operates by the mechanism of plasticity rather than abrasion. In practice, this means that less material is removed by the process, and less dust created.

Grit blasting however is more powerful and used to smooth, shape, or clean a surface. The effect can be said to be similar to using sandpaper, but provides an even finish with no issues at corners. There are many variations of grit blasting, and you may know it through one of its many names.

Some variations of grit blasting include sand blasting, wet abrasive blasting, bead blasting, wheel blasting, hydro-blasting, micro-abrasive blasting, automated blasting, and dry ice blasting. Each of these may include differences in techniques, but all provide very similar finishes.

Grit blasting is the more widely-known technique when compared to shot peening, and in some instances can be more effective at achieving the finish or clean up that you would like.