The Basics of Shot Blasting
In Philadelphia in 1870, Benjamin Chew Tilghman created a machine that would revolutionize floor removal: the shot blaster. Today, shot blasting is often the first floor removal choice for experienced surface preparation contractors. It is a one-step method for stripping, cleaning and profiling both concrete and steel surfaces. It leaves the surface clean, dry and ready to be recoated or resurfaced.
Shot blasting works by using a centrifugal wheel that propels steel shots at a high velocity in a controlled pattern and direction. As the wheel hits the concrete surface, the outer layers are removed, leaving a smooth surface behind.
The process of shot blasting features a recovery system that incorporates a vacuum. It is imperative to the process that users pair the shot blaster with a dust collector that has the correct cubic feet per minute (CFM) rating. A built-in air-wash separation system cleans and removes the debris as the reusable steel abrasive is gravity-fed back into the shot hopper.
An alternative method to shot blasting is diamond grinding, in which grit sanding pads of various sizes are attached to a grinding machine. The machine then passes over the concrete to smooth the surface. However, diamond grinding is generally a much more expensive process.
The original stationary shot blaster has been in operation for decades, but when the US Navy required a machine that could remove non-slip materials and paint from the floors of their aircraft carriers, the portable shot blaster was developed. Today’s shot blasters are available in walk-behind electric models or propane ride-on units that feature an on-board dust collection system.
Good floor preparation experts will choose the type of shot blaster they want to use based on the job size, budget, production requirements, materials and desired end-result. The power of the machine and the steel shot size are also important factors when choosing a shot blaster because they can help achieve different concrete surface profiles (CSP) and affect production rates. Shot blasters can produce a range of CSPs, from a light brush blast to an exposed aggregate profile, which makes them perfect for residential and commercial surface preparation.
For more information about National Flooring Equipment’s products, visit nationalequipment.com.