A shot blaster throws steel shot at a concrete floor and vacuums the shot and the debris straight back up, leaving a clean profiled surface with very little airborne dust. Walk behind machines rent for roughly $200 to $450 a day depending on blast width. What catches people out is the electrical supply and the shot, which is a consumable you pay for.
Why a blaster instead of a grinder
A shot blaster profiles a large open floor faster than anything else and leaves the texture a coating needs to key into. It also collects its own debris mechanically rather than throwing it into the air. A grinder is the better machine for small rooms, for edges, for smoothing rather than roughening, and for polishing.
The power supply decides which machine you can have
Eight and ten inch units run on a heavy single phase circuit that many buildings can give. Fifteen inch and larger machines want three phase, and on a site without it that means a generator sized for the motor starting load rather than its running load. Check the panel and the breaker before you book, not on the morning.
Shot is billed as a consumable
The machine recycles shot through a separator and loses a share of it every hour through the seals and with the dust. Yards supply it by the bag and charge what you use. A blast pattern that goes weak usually means the hopper is low or the perimeter seals are worn, and both are worth checking before you blame the machine.
What it will not remove
Thick elastomeric coatings, carpet adhesive and soft toppings smear and clog rather than break away, and the machine will chase them across the floor. Those need a grinder, a scarifier or a shot blast after the bulk is off. A blaster also cannot reach within an inch or two of a wall, so edges are hand work.
Questions people ask about shot blaster rental
How much floor can one machine cover in a day?
A ten inch walk behind on clean concrete with a light profile will cover a few thousand square feet in a shift. Heavy coating removal on the same machine may be a quarter of that. Blast width and how many passes the surface needs are the two variables, so measure the area and describe the coating.
Is shot blasting really dustless?
Near enough, provided the dust collector is attached, the filters are clean and the hopper is emptied. Concrete dust contains respirable silica, so the collector is the control and not an accessory, and it is worth confirming the collector comes with the machine rather than as a separate line.
Do I need experience to run one?
It is a walk behind machine and the technique is mostly steady overlapping passes at a constant speed. The learnable part is setting the blast pattern and the travel speed for the profile you want, so ask the yard to set the machine for your coating and do a test area in a corner first.