Sandblasting
Sandblasting is the carefully controlled bombardment of a surface with abrasive sand or grit propelled at high speeds by compressed air. Sandblasting can be used to clean surfaces, apply decorative texture, or to sculpt glass, wood, or stone. The sand or grit particles are a health hazard and proper protective equipment must be used when sandblasting.Uses for Sandblasting
There are four basic uses for sandblasting.
Cleaning – Sandblasting is used to clean sand and irregularities from foundry castings. The process can also be used to strip away accumulations of rust, dirt, and old paint or varnish. This must be done with caution so as not to damage the underlying surface.
Texturing – Sandblasting can be used to texture many surfaces, but is particularly useful for making decorative designs in concrete floors, walls, and columns. This technique can also be used to clean and rough up a concrete surface prior to tiling. This ensures a good bond between the concrete and the tile adhesive.
Etching and Engraving – Fine sandblasting can be used to engrave glass, crystal, ceramic, acrylics, stainless steel, aluminum, brass, pewter, bronze, granite, marble, and wood. It is even possible to reproduce a photographic image in glass or metal using sandblasting.
Sandcarving – An artisan can use carefully controlled fine sandblasting to sculpt and carve in three dimensions on wood, glass, or stone.
Decorative Techniques
Decorative sandblasting involves the use of a stencil or ‘mask' that is applied to the surface. The mask protects the areas that will not be decorated.
For simple images on concrete, the mask can be made from any material that will withstand the sandblasting. For complex images on concrete or other materials, there are various mask products made specifically for sandblasting. These masks have an adhesive backing and adhere to the surface being decorated. Depending on the application, masks can be purchased in various designs, created from computer artwork or photographs, or drawn freehand.
After the mask is applied, the surface is sandblasted. During this process, it is important to keep the nozzle pointed straight at the surface; if the nozzle is at an angle, the abrasive may get under the mask and ruin the decoration. An even application of sandblasting is usually desired. After the sandblasting is complete, the mask is removed by peeling it off or, if necessary, soaking it in warm water.
Health Hazards
If a person inhales the fine sand used in sandblasting, the particles lodge in and irritate the lungs. The lungs respond by forming fibrous scar tissue around the trapped particles. This condition is called silicosis.
It is extremely important either to use an enclosed sandblasting cabinet or to wear appropriate and well-maintained respiratory protection equipment while sandblasting. Other workers who are in the vicinity of sandblasting operations should also use respiratory protection equipment.