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Choose the Right Surface Grinder Attachment
Basic Guidelines on Choosing the Right Surface Grinder Attachment
Always consult your machine's operator’s manual for details on the specific surface grinder being used.
General Equipment Company Surface grinders are versatile tools, able to tackle projects like surface preparation, coatings removal, and polishing concrete. But they do require different types of attachments depending on the job. Some attachments are specialized for a single specific use, while others can work for multiple concrete applications. Unfortunately, it is not always obvious to determine the best-performing attachment for a particular jobsite.
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1. SILICON CARBIDE
GRINDING STONES
Silicon carbide grinding stones are easyto-use and cost-effective to prepare the surface for various coatings, ranging from 6 to 120-grit. Six- and 10-grit stones provide maximum material removal rates— perfect for removing trowel marks, high spots and rough sections on concrete surfaces. 24-grit stones have a lower removal rate but provide a finer finish when grinding concrete. They can also be used for rough grinding on terrazzo and other types of stone floors. 80- and 120-grit are great for polishing concrete but can also be used for medium grinding on terrazzo and other stone floors when used with a water slurry/mixture. Six-grit stones may last 4-10 hours, while 120-grit stones may last up to 75 hours.
Although these attachments work very well for surface preparation, they should not be used to remove existing coatings from concrete. The pores clog with material quickly, rendering them ineffective in short order.
2. TUNGSTEN CARBIDE
ATTACHMENTS
Tungsten carbide grinding attachments are used mostly on large concrete grinding projects where increased production and service life are needed, as these attachments are considerably more aggressive than a course 10-grit silicone carbide grinding stone. Tungsten carbide has a much longer service life as well. In fact, normal life expectancy for this accessory can approach several hundred hours.
3. SCARIFIER ATTACHMENTS
Scarifier attachments feature flails and spacer washers in a steel case. Different types create a variety of results, so consider the type and amount of material to be removed from the work surface, purchase cost versus service life, and the surface finish and texture.
The star flail is made of high-carbon hardened steel and are a solid, low-cost solution for light cleaning or scarifying, as they create a fine surface texture.
Beam flails are shaped differently for other applications. These are often recommended for medium-duty concrete and asphalt scarifying, descaling steel decks, removing thick material build-ups of grease, paint, oil, vegetable powders and some resins from floors, or removing carpet and tile adhesive that is dried and fully cured. Beam flails leave a fairly smooth finish.
Pentagonal flails are designed for more aggressive and rapid removal of a surface than a beam flail can achieve. They create a rather coarse surface texture, making them more suitable for heavy-duty concrete and asphalt scarifying, as well as heavyduty descaling of steel decks.
4. ANGLED TUNGSTEN
CARBIDE INSERTS
Designed for floor coating removal, tungsten carbide inserts are set at a precise angle to create effective scraping action. Productivity rates depend on the tensile strength and thickness of the material being removed. Rule of thumb: if the coating is thick enough to cut or pry away with a knife, then use tungsten carbide.
Materials such as adhesives, rubber deposits and mastics have a tendency to extrude or smear rather than shear off from the concrete surface, especially in high ambient temperatures. This can be eased by adding either water or a mixture of sand and water.
5. DIAMOND SYSTEMS
Attachments that utilize diamonds offer superior longevity and production rates for surface grinding and coatings
removal applications. Contrary to tungsten carbide systems being most appropriate for removing thicker coatings, diamond systems are best for removing thin coatings no greater than 1/16 in.
There are a few types of diamond systems available. Multi-segmented dry diamond discs are designed to operate dry but can also be used with water. These fasten directly to the surface grinder’s gimbal head to provide very fast concrete removal rates.
Diamond segment attachments deliver up to five times greater productivity rates than silicon carbide stones, while having a service life up to 15 times longer. Because diamonds have an anti-clogging characteristic, they are an ideal choice for removing epoxies, paints and many thin film coatings, as well as large concrete removal projects. They are also an excellent choice for prepping and smoothing, readying the surface for a topcoat, or polishing.
A PCD (polycrystalline diamond) tooling is comprised of a diamond grit fused together with a catalytic metal. These attachments are recommended for removing thin-to-medium glues, mastics, covering materials and cement levelers from concrete surfaces. Sacrificial segments allow aggressive removal rates by the attachment’s PCD inserts while also acting as a stabilizer/ depth guide to minimize the potential for surface damage.
It’s important to know how diamond systems are constructed to choose the best for a particular application. The diamonds are embedded in a matrix. During use, the matrix wears away to expose the diamonds. The bond hardness of this matrix varies from one diamond system to another. Ideally, choose a hard bond when grinding soft materials and a soft bond when grinding hard materials, as softer materials wear diamonds more quickly.
These attachments come at a premium price when compared with silicone carbide grinding stones, but also provide much higher productivity and service life. It comes down to how often a contractor will be using the grinder. If it’s a one-off job, then going with the cheaper, short lifespan grinding stones may be the smarter choice. But for a regular duty machine, diamonds can be much more cost effective in the long run.
To maximize productivity, be sure to replace or rotate attachments as necessary. If required, contact the equipment manufacturer to determine the life expectancy of each attachment. Always consult the operator’s manual for details on the specific surface grinder being used. For additional assistance, check with the manufacturer or your local distributor or rental center.
Dennis Von Ruden is President of General Equipment Company.
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