Sandblasting is a general term used to denote the process of propelling tiny bits of solid material on a surface at a high speed using compressed air to clean or etch it. As the term denotes, finely ground sand is used for this process. The purpose is generally to clean off dirt or rust or paint off the surface. It is used to clean parts of ships and large structures like bridges. The Golden Gate Bridge is cleaned using this process.
The equipment has three parts: the abrasive blasting Sydney, the air compressor and the nozzle. There are 3 types of blasters; the first type is gravity-fed which has 3 compartments, the air tank, a manually operated pressure gun with air hose and a hopper on top of it. As you hold down the trigger of the pressure gun, compressed air passes rapidly through it and releases the opening connecting with the hopper. The force of gravity and the force of air sends the sand through and out of the barrel.
The second kind is the pressure blaster. This finds use in commercial projects and consists of a large canister of silica kept under high pressure. A two handed blasting gun connects to the top of this canister with a hose. When the trigger is pulled, both air and sand flow out at great speed. The third is the siphon blaster. It is cheaper and handier and has two separate houses. One connects to the bottom of the handle and the second to the bottom of the barrel. There is an air hose that connects to the compressor and there is another hose connected to the sand reservoir. When you fire the gun, the air sucks out the sand from the sand reservoir and sends it up the hose into the gun and out of the barrel.
The gun in all sandblasters has a ceramic barrel or a coating on the inside to prevent erosion. However, due to health concerns caused by silica, corn cobs, glass beads, steel grit, shells of coconut and walnut are also being used hough sand still remains the popular choice. This technique is very popular in glass etching since it saves time and costs much less than manual etching. You can manipulate the speed and angle of the blasting in such a way so that it will have the desired effect on the glass surface.
It has been noticed however, that though this is an effective process, it also has several risk factors. It poses serious health hazards, especially from inhaling silica and lead particles. So blasting is done only under carefully guarded environment and a great deal of care is given to ensure that the area is properly ventilated and that the amount of dust generated does not cross the allowable limits. Another safety measure is the mandatory use of the helmet that is so devised so that it moves with the movement of the operator’s head. It also has a viewing window fitted with lenses. It is mandatory to use Grade-D air for protection or use an oil-free pump. Workers must also use ear plugs and gloves and coats or suits appropriately tailored for maximum protection. But provided that the prescribed safety measures are followed, this technique can be used safely and usefully.