Concrete surface grinders are used to clean concrete and to remove coatings, mastics, urethane, epoxy or paint. They are also used to level out high spots on a concrete surface or grind down trip hazards at expansion joints and cracks. Specialized applications include terrazzo, marble, or granite polishing, and decorative concrete applications. Grinders work by using a grinding disc or wheel that is embedded with an abrasive media (usually either diamond chips, carbide or in the case of abrasive discs, with silicon carbide). The diamond chips or silicon carbide abrade or cut the surface that is being prepared, removing paint, coatings and surface contaminants.

Concrete grinders are available in a wide range of configurations to match specific job requirements: hand-held, walk-behind/dolly-mounted, dustless, multiple head and single head. Hand-held grinders are small grinders used for edge work and for small jobs. They are usually 5 or 7 inches in diameter, with a single head. They are available in dustless models, some with convertible dust shrouds that allow for edge work. Walk-behind/dolly-mounted grinders can range from 7 inch to much larger sizes, in single head or multiple head systems. Some systems are dustless. Some can be used with water. Dustless grinders use a dust shroud that collects and routes dust to a separate dust collection system. Dustless systems save time on cleanup, and allow other trades to work in the same area at the same time. They are also more popular with operators because they are cleaner to use. Dustless grinders are usually available in a wide range of sizes, from 5 inch to larger sizes. Larger grinders are typically available in multiple head configurations. This type of machine uses diamond plugs or carbide cutters that are affixed to rotating heads. The heads are arranged in an overlapping pattern. Multiple head grinders may be dustless. Some are also used with water. Single head systems are typically found in smaller grinders. Single head systems use a single cup wheel or abrasive grinding disc. They may be dustless.

To ensure that you have the right grinder and abrasive for the job, be sure to consider (1) the type of coating or other contaminant that is being removed. In other words, the application. (2) the psi of the concrete surface, taking into account the age of the concrete surface. Concrete hardens as it ages. The hardness of the surface helps determine the type of cup wheel, abrasive disc or cutters you should use. (3) the geographic location of the job site. Concrete aggregate hardness varies by region of the country. Aggregate hardness helps determine the type of cup wheel, abrasive disc or cutters that you should use. (4) the size of the job (square feet), used to determine the size tool needed. (5) the power sources available at the job site. Grinders are available in electric or propane models.

Before operation, operators should read and understand the manufacturers' equipment manuals prior to using the equipment. They should wear eye protection, hearing protection, safety shoes, and especially when emptying dust collectors, should wear breathing protection and gloves to minimize exposure to concrete dust. Specialized equipment may be required if the job site involves lead based paint or other hazardous materials. The operator should always inspect the grinder and cup wheel, abrasive disc or cutters prior to use. Never use a damaged grinder, cup wheel, abrasive disc or cutters. Only use cup wheels, abrasive discs, plugs and cutters that are appropriate to the grinder type and RPM. If applicable, check the arbor bearing for end play, and ensure that all fittings are tight prior to use.

Routine maintenance tips: keep your grinders in good running condition.

Electric grinders - Check grinder motor brushes. Clean out excess dust. Inspect power cords.

Gas motors (DC) - Change oil and follow manufacturers' recommendations for motor maintenance.

Propane units - Maintain proper grease levels. Verify that tool holders and blocks are secure and not damaged. Clear dust ports and hoses of dust. Follow manufacturers' recommendations for motor maintenance.

General: inspect tools prior to use to ensure that they are in good condition. Replace worn or damaged parts.

Sawtec, a division of USF Surface Preparation Group, offers a full line of portable, virtually dust-free surface preparation equipment including air-powered saws; grinding equipment; tile-cutting and tuckpointing tools, crack-chasing saws; joint-cleanout saws; and dust-collection systems. The Sawtec line also includes a full complement of standard and premium diamond blades, cup wheels and abrasive discs. Sawtec sales professionals work with knowledgeable equipment and supply vendors and are available for consultation at your job site to help determine which tool and diamond blade will best serve your needs.

Call Sawtec at 800-624-7832.

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