Using a shot blaster to clean and prep a concrete floor for another coating is a popular method of surface prep. These machines have a variety of blasting widths and power requirements, but virtually all of them require the same fundamental adjustments to work properly. Keep reading for National’s troubleshooting tips for a shot blaster that is dropping shot.
Setting up your machine properly at the jobsite can prevent your machine from dropping shot. Do this by charging/loading the magnets on the bottom of your blaster. Using a hand magnet, take shot from your bucket, drop it on the ground, and run your blaster over it. This will create a curtain of shot on the three magnets on the bottom.
National Flooring Equipment’s A95, A96, and A97 shot blasters are all designed with the three-magnet design on the bottom. The front, and two sides of the blasting width have magnets that will collect the loose shot you pour on the ground. This design keeps the propelling shot contained so it doesn’t get thrown out under the blaster as it is rebounding. The back side of the machine has a brush to allow for airflow, and to keep large debris contained.
After building your shot curtain, fill the shot up to the bottom of the screen in the hopper. Don’t overfill this, as it interferes with the machine’s ability to get a tight seal in the hopper. This potential gap, in turn, doesn’t allow for proper shot flow.
After filling the hopper, slowly move the shot blaster forward as you open your shot valve. If you go to fast, the physically doesn’t have enough time to engage all of it’s internal components. The motor needs time to warm up and turn the blast wheel fast enough for the shot to hit the ground and rebound back up.
Next, make sure you are not pulling more than 20Amps. Your amp draw should be around 17 Amps. If you are pulling 20 Amps you are pulling so much shot through the blast wheel you are overloading it. Pulling too many amps is flooding your machine so it can’t operate properly.
Also, check your dust collector. Poor suction will impact your performance. Clean and purge filters so you get plenty of suction. Make sure you have the right CFM with the right model of machine. Too small. Of a CFM won’t separate dust and won’t assist in proper rebound. If it’s too large it will suck the media right out of the machine and into the dust collector.