What is Shot Blasting?
Shot blasting is a technique used for the purpose of surface finishing. Fortunately, it is a dust-free alternative and also saves on time and labor. With shot blasting there are none of the hassles associated with other methods used for surface preparation and you do not have to worry about expensive disposal procedures. In fact, shot blasting is fast becoming the preferred method among coating manufacturers since it produces great bonding characteristics that reduce instances of coating failure and increases floor life. Shot blasting is also used to remove scale, burrs, graffiti and rust from any surface.
How Does It Work?
The main principle of shot blasting lies in propelling a controlled stream of abrasive shot material rapidly towards the surface being targeted. At the heart of the shot blasting system lies a blast wheel. As the wheel rotates at high speed, the metallic abrasive (also known as media) is channelized to its center, from where it is accelerated and hurled in the direction of the surface being prepared. The contaminants as well as the media rebound into a separation system that contains a dust collector. The function of the dust collector is to remove the dust, contaminants and any media that has been pulverized. The remaining media can be recycled by returning it to the storage hopper for future use.
Different Methods of Shot Blasting
Sand is the most common abrasive used for shot blasting, and therefore the process is generally referred to as sandblasting. The other abrasives used for shot blasting are garnet, chilled iron, olivine and glass beads. The first two are extremely coarse and abrasive and they are not to be used on soft surfaces. However, olivine and glass beads are generally used as polishing agents and they can be used on delicate surfaces like metals, plastic, rubber and glass.
Advantages of Shot Blasting
There are several advantages to choosing shot blasting over other conventional techniques used to prepare surfaces. For one, you can avoid using harsh chemicals that are not eco-friendly. Additionally, you can select from among a wide range of abrasives and you can use this process indoors as well as outdoors. With this process, the surface is dry almost immediately and there is no accompanying dust pollution.
Workers who carry out the process of shot blasting are exposed to certain hazards and adequate protection is required to keep them safe. One of the most serious hazards is airborne dust which can invade the respiratory system and cause damage. Metal dust can also be very dangerous since metals like lead, cadmium and manganese can be toxic if inhaled.
For this reason, regulations demand that the media be handled by trained personnel, wearing protective clothing and masks in the presence of medical monitoring. Also, hearing protection for all workers is a must and operators should also wear leather gloves, leggings and aprons when on the job.