When facing any surface preparation job, from a small, residential floor to a huge industrial facility, contractors must properly assess the job site to establish what equipment will complete the job at the most efficient production rate.
When choosing between a grinder and a shot blaster for doing surface preparation, you should consider the desired profile and end result. Choosing the right tool for the job is why so many surface preparation contractors have a wide assortment of equipment in their fleet. There is no single solution that works in all applications.
There are a few factors that drive contractors to choose a shot blaster over a grinder. Steel shot compared to diamond tooling is a much cheaper consumable in the profiling process. Shot blasting is a faster and more efficient process, which lowers labor costs for the contractor. Shot blasters clean and profile the floor in one quick and efficient step, while grinding requires you to vacuum the floor after the work is done. Using shot blasters requires little clean up, meaning that contractors can immediately apply a new coating after preparing the floor.
Shot blasting also allows the contractor to create a higher, more aggressive concrete surface profile (CSP) that grinding cannot achieve. CSP is a measure of the distance from the peak of the surface to the valley of the cut. This is a one-through-nine standard with CSP-1 being the smoothest.
Size
Shot blasters come in many sizes and widths to suit each job. Contractors must always assess a work site before approaching a rental company for surface preparation equipment. Look at the size of the room and any obstacles that may impact equipment choice. In most circumstances, a larger shot blaster is recommended for larger buildings to get the best production rate. Similarly, in small jobs, a smaller blaster will be more efficient because the machine is more compact for easier maneuverability in smaller spaces.
However, assuming large square footage always requires large machinery is a common misconception in surface preparation. For example, a hospital is a large building split into individual rooms that a larger machine may not be able to fit into. In this application, smaller equipment will more easily maneuver between rooms.
Return on investment
When looking to purchase a shot blaster, contractors should prioritize purchasing smaller equipment. Contractors can use smaller machines for a range of jobs and then move to larger equipment as they win larger contracts. During work on larger spaces, small equipment will still be useful to maneuver around tight spaces and corners that a larger machine may struggle with.
Contractors can also use handheld shot blasters if they are faced with tricky jobs. A handheld shot blaster is the only machine of its type that can be used for horizontal and vertical applications. This makes it the best choice for smaller, tight areas and awkward spaces, such as staircases.
Accessibility
Accessibility to the site itself is an important consideration when choosing equipment. Contractors should evaluate how equipment will enter a site when first viewing the space. While a larger machine will be more efficient in a large space, it may be difficult to maneuver upstairs or in small hallways.
Power source accessibility is also important because shot blasters require an electrical socket. When assessing a site, locate all wall sockets and predict how their placement will impact the job. Contractors can prepare for jobs with little access to power supply by purchasing generators and extension cords to ensure the machine can run at full capacity throughout the project.
Tooling
Surface preparation equipment is most efficient when contractors choose the correct tooling. Steel shot is the main consumable when using a shot blaster because it impacts the surface, preparing it for a new covering. Contractors must estimate how long a job will take with the equipment size they have rented to determine how much shot they need.
The shot is added to the shot hopper that then feeds into the blast wheel inside the machine. This will wear throughout the work and has a lifespan of around 40 hours. If you think a job will take longer, buy additional blast wheels. The tooling is quickly and easily replaced on site, helping contractors to efficiently complete work in one session.
Another important tool is a magnetic sweeper, which collects shot left behind on the surface. If the surface is to be completed using just a shot blaster, ensure the area is clean and ready to be used. Leftover shot can be seen under thin coatings if not properly removed.
Operations
Shot blasters are simple and easy to operate. They work off two basic principles: rebound and vacuum. Start by loading steel shot into the hopper. Turn on the vacuum and engage the blast wheel. Start moving the machine across the surface. Once the machine’s in motion, slowly open the valve that feeds the shot into the blast wheel.
The blast wheel propels the shot onto the surface. The high volume of shot creates countless impacts per square inch, creating the best profile for bonding. The shot travels up the rebound plenum (curved front part) and returns to the shot hopper to cycle back through the system. As the shot returns to the shot hopper and falls back down, dust is pulled away and removed by the vacuum.
Contractors have many factors to consider to ensure surface preparation success. From the first assessment, to cleaning up post-construction, contractors can follow the advice of rental companies and training, to choose the right equipment for the job.
