Video made by Blastrac.
Shot blasting (bead blasting) utilizes a highly specialized machine best used in the restoration and the surface preparation markets. There are many ways to use a shot blaster with many different results. We use our 40 plus years of experience to best match the process to each job.
When preparing a floor for a thick coating, floor cap, moisture barrier, traffic coating or tile, you would want an aggressive profile. This is done by running the drive speed of the machine slower while using larger steel shot. This will result in a rough exposure that will give a very open profile in the concrete. This ensures the highest bond, which greatly reduces failure rates in adhesion versus an unblasted floor.
When used as a decorative finish you would want a light profile on the concrete. This can be achieved by running smaller steel shot thought the machine while running the drive speed faster. This is excellent if you plan to have a thin coating, sealer or bare floor. The light profile allows the floor to be cleaned and the cap to be opened, but not removed.
Using a shot blaster on a damaged or aged floor will allow the even removal of concrete across all elevations on the slab. Unlike using a grinder for prep, you clean all spalls, holes, cracks and expansion joints. The down cut pattern means you can even blast stamped concrete with out removing all of the stamp, as well as having the ability to provide more aggressive profiles then possible with grinding. Many coating manufacturers require shot blasting for their warranty to be effective. Make sure when you hire a shot blaster they know what they are doing and make sure they are licensed before they work on your floor. Shot blasters are powerful machines and a large amount of damage can be done if run by an inexperienced operator.
This quick video made by Blastrac, the world's largest shot blast manufacturer, has an informative animation on how the machine operates.