What Is Concrete Shot Blasting?

What Is Concrete Shot Blasting?

Shot blasting concrete is a resurfacing technique that uses metal beads that are “shot” out of a machine to “blast” away tough debris and residues.

It’s similar to sand blasting, but the size and speed of the metal pellets offer a far more forceful clean.

Shot blasting concrete is important for concrete structures that are in poor condition (for instance, a concrete beach wall that is being worn away by waves or rocks), but also of use for revitalizing existing surfaces or places where deterioration is common.

The shot-blasting process occurs in three steps: the “pre-treat”, the “blasting system” and the “finish” process; these are separated into separate processes, and performed at different locations.

The working methods are similar to sandblasting and paint-blasting: a blasting machine (sometimes referred to as a “bead blaster”) is used to shoot out projectiles consisting of metal beads. The process creates a vacuum in the concrete resulting in beads of concrete debris being removed.

How Does Concrete Shot Blasting Work?

Shot blasting is a process that involves steel shot being propelled at high velocity at a close range to a surface, typically concrete or metal. 

Shot blasting machines fire metal beads at the concrete using a centrifugal blast wheel.

The beads are channeled in while the wheel turns, shooting them out via a gap directed towards the concrete surface. The metal beads’ rapid velocity scrapes away the top layer, exposing a cleaner surface.

Because the steel shot hits at such a force, it quickly chips away and etches at the top layer, and the broken up layer is then automatically suctioned into a connected dust collector while the shot is pulled back into the machine and reused.

Whether the top layer is compacted dirt, rust, or an epoxy coating, the shot is able to blast it away, leaving a clean, bare surface.

The entire process is contained by shot blasting equipment. The trash is vacuumed into a dust collector, while the metal beads are cycled back into the process.

What Is The Difference Between Sandblasting And Shot Blasting?

Shot Blasting and Sandblasting are similar in that the media for both is metal shot. However, one method is generally easier to use.

When it comes to metal surfaces, sandblasting is a great choice because it can be done with compressed air or water. This technique is simple, though it can be quite dusty and hazardous as it uses sandpipes to shoot the shot media at high speeds through the space being cleaned.

Shot blasting is more forgiving, because it can use machine-mounted rotary blasters that use rotating wheels to fire a prepacked media at the surface.

Shot blasting and Sandblasting both clean concrete surfaces, but one is usually easier to use. Shot blasting uses sandblasting’s media, but is more forgiving of imperfections in the surface than sandblasting.

When it comes to hard, metal surfaces such as brass fixtures and steel rebar, shot blasting should be your first choice. It can be used on these surfaces because of the size and speed of the shot media.

On a brass item, the high-velocity nature of shot blasting will dislodge any buildup or rust that has developed on the surface. By sandblasting this same surface, you will just have an even messier surface afterwards.

The main difference is that shot-blasting uses abrasive “shot” made of metal such as aluminum oxide or carbon grit almost exclusively.

Sandblasting can use metallic shot, but more often it uses gentler abrasives such as organic media or glass. Silica sand used to be the more popular abrasive choice and is the choice that gave sand-blasting its name.

However, most modern facilities rarely use sand these days because of its potential for causing