Blast off that Dirt, Paint, Rust and Debris
The meaning of the term sandblasting
Sandblasting is a general term used to describe a cleaning method where tiny bits of a substance or a metal are forced at high velocity through a pressured device against a wall, steel, copper, or some other material to be cleaned. The term “sandblasting” goes back to the nineteenth century when an inventor developed a method of cleaning rust and paint from the surface of buildings. At that time, sand was the only media used and became the general descriptor of the process.
Regardless of the types of bits that are used, certain types of sandblasting raise dust, dirt, and anything else around it. Operators have to be very careful to wear appropriate protective clothing and have their face covered. During training, they are taught to wear dust or safety goggles and a specially designed sandblasting suit.
Sandblasting can be easily described by imagining a watermelon seed. When one watermelon seed is shot at you, you may laugh. If dozens of watermelon seeds hit you over and over, regardless of how small, they will leave a bruise, which is exactly what sandblasting does. It bruises and bites into the material being cleaned removing any loose particles. As the name implies, it blasts away surface debris.
How to become a sandblaster
As with most types of construction work, sandblasting is a specialized job that requires certification and training. The powerful equipment is capable of peeling plated metal, thick paint, and removing wood siding, instantly. Workers who are interested in operating a sandblaster should have a couple of years of construction experience as well as being very safety conscious.
In order to be considered for certification, a trainee will first work with a certified operator who will guide them through all of the nuances of the device. This initial training is very critical for the successful completion of the certification course serving as a hands on guide to the process. During the initial training, students learn the different types of media and experience its use. The quality of the training, at the practical level, depends a great deal on the skill of the trainer and their ability to serve as a mentor.
There are state and federal regulations regarding the operation of a sandblaster, which is covered in classroom work where the trainee will learn the regulations as well as how to apply them to unique situations. A portion of the class work includes an understanding of explosives their properties, handling, transportation, and uses. Other sections cover the different designs of sandblasting. For full certification, 32 hours of classroom time is required and recommended.
Certification is given through the Office of Surface Mining Reclamation and Enforcement or OSMRE, which requires that the final step of certification be completed within three years of the certification application. OSMRE will accept equivalent experience as long as it meets their specific standards. Certification has to be renewed every year and must be current.
What are the uses of a sandblaster?
A sandblaster is designed to clean small rings to the side of a building. Though we may commonly think of it as construction equipment, it is an important tool in several other industries such artistic creations, wood finishing, and auto assembly.
When sandblasting was first used in the creation of art works, the artists did not have precise enough control to create a smooth design. As the technology of sandblasters and its media has developed, it has become a precision tool that can shape stone and wood into delicate designs.
When making wood tables and chairs, it may be necessary to prepare the surface before assembly and finishing. A sandblaster will remove oils or finishes that may be on the wood surface left from milling. The prepared surface can be more efficiently assembled and able to accept the application of the final finishing coat.
In the auto industry, parts from vendors arrive with a protective oil or grease. Before they can be installed in the car, they need to be cleaned. It has been found that sandblasting is a quick and reliable tool for removing any of the grim on the parts. Its efficient use speeds up the assembly process eliminating wasted time.
The different types of sandblasting
Over the years, sandblasting has moved from a man holding a sandblasting gun to different methods designed to fit specific situations. The changes also include different ways of feeding the media into the sandblasting device. A combination of the different types of blasters, media, and kinds of feeding has created modern sandblasting.
Sandblasting cabinet – A sandblasting cabinet can be large and fixed in place or small enough to be carried. The sizes vary from ones that will fit on a table to larger versions with a big cabinet and four legs. The tabletop versions can be used for the production of small projects such as cleaning china, silverware, or artistic creations. The large cabinets can hold doors, windows, and large auto parts. As with all sandblasting, the cabinets use pressure and a media like the handheld version. A built in feature of cabinets is a dust collector to remove dust and debris during the sandblasting process.
Mini Sandblaster – This type of sandblaster is for the hobbyist working on a project at home. It is very similar to the watermelon seed example but using sand as the media. Mini blasters can be used to clean designer jewelry or ceramics. The process involves pouring sand into a funnel placed over the item to be cleaned. As the sand leaves the funnel, it pelts the piece cleaning off surface imperfections and particles.
Shot blasting – Shot blasting is very similar to sandblasting. The difference is in the media that is used, which can be some kind of metal abrasive such as copper, steel grit, or aluminum pellets. The shots can be delivered through a pressured fluid or centrifugal wheel. Shot blasting, like sandblasting, removes rust, paint, scale, and other imperfections from metal.
Shot peening – The purpose of sandblasting is to clean something such as wood, metal, or plastic of dust, dirt, grim, and debris. Unlike the cleaning function of a sandblaster, the peening process is designed to improve and strengthen the material properties of a metal. In its basic form, peening is done with a ball peen hammer pounding a metal into a shape. The media in shot peening is similar to small ball peen hammers that are blasted against the metal creating compressive stress strengthening the metal as it reshapes it.
Different types of media
The original purpose of sandblasting was to remove dirt, paint, and other grim or debris. Sand, under pressure, was forced against a surface until the desired appearance was achieved. As the process has been improved and perfected, there have been several changes to make it more precise and efficient. Much like deburring or vibrating tumbling and finishing done by hobbyists, sandblasting has been refined to the point that it can pinpoint what needs to be removed without doing harm. This is accomplished through various kinds of media.
Glass – Glass media is used to produce a brighter shinier finish. It is less abrasive than other media such as steel or silicon and can be used to finish and polish metals. It comes in a crushed form or beads depending on the application.
Aluminum – Aluminum media is highly abrasive and is used for roughing a pathway to cleaning parts in a factory. Its aggressive nature makes it ideal for any type of surface regardless of the density or hardness. Since aluminum media is so efficient, it is ideal for preparing a surface for painting or applying a deep coat. One of its attractive features is that it does not break down or produce dust
Corn – Corn media is a mild abrasive that can be used on materials requiring a delicate and precise cleaning. Since corn is grown and not formed, it is biodegradable and environmentally friendly. Unlike more aggressive media, it will not etch or harm the item being blasted.
Pumice – Pumice media is an extremely gentle abrasive. It is used where protection and preservation of the surface is important as well as precision. The outstanding feature of pumice is its friability, the ability to be ground into a powder but still be an abrasive. Pumice’s sensitivity and gentleness makes it ideal for use with fragile electronic parts such as circuit boards or intrigue components.
Steel grit – Steel grit is one of the most aggressive of the media. It works fast and can completely cleanse whatever it is cleaning. In manufacturing, it is used to clean castings, stainless steel parts, and to strip away any contaminates. Due to its aggressive nature, steel grit will smooth edges and remove burrs.
What has been described is just a few of the many media available. The type of media is very dependent on the job. It is important to choose carefully since a misuse of sandblasting can destroy what is being cleaned by reshaping it.
The final word
Sandblasting is an ideal tool that can fit into any work environment requiring deep and precise cleaning. When making the choice to use it, safety must be the primary consideration. Blasting is an aggressive way to clean and smooth things, which makes it very attractive. It does produce dust that can be harmful requiring proper equipment and coverings. The end product is very dependent on careful planning and preparation.