Grinders use horizontally rotating cutting discs to clean and smooth concrete surfaces. You also can use grinders on stone, tile and other masonry surfaces depending upon the type of cutting discs you attach to them. Concrete finishing and repair contractors, flooring contractors, general contractors and homeowners rent grinders to perform a number of surface-preparation functions on concrete. These tasks include:
- Smoothing. Smooth out rough concrete or trowel patterns in concrete surfaces.
- Leveling. Level an uneven area if high spots or differences in concrete height on either side of the joint measure no more than 1/16-inch.
- Cleaning. Clean concrete surfaces of rust, grease and mildew.
- Removing coatings. Scrape old paint, epoxy, adhesives, urethane or other coatings from concrete surfaces. Grinders typically can remove materials up to 1/16-inch-thick.
- Polishing. Polish marble, granite, stone or decorative concrete surfaces by attaching a polishing pad to a rented grinder.
Your local, ARA-affiliated rental store may offer many types of grinders for rent. The following material describes differences between the types of grinders possibly available.
- Walk-behind or dolly-mounted grinders. These rental grinders can contain one or multiple discs. The size of the discs can range from 7 to 10 inches or more. Industrial grinders provide an excellent means of accomplishing heavy-duty grinding applications.
- Hand-held grinders. Renting a lightweight, hand-held grinder may suffice for small grinding jobs or edge work. They can also be used to remove graffiti from some surfaces. These grinders typically accommodate 5- or 7-inch grinding discs.
- Edge grinders. Rent this type of grinder to grind areas near walls and corners and other areas often missed by larger grinders.
- Ceiling grinders. Rent this type of grinder to smooth concrete ceilings of burrs and rough areas.
Considerations when renting a grinder
When you go to rent a grinder at your local ARA-affiliated rental store, tell the rental professionals about the project that you plan to complete, so that they can advise you on which grinder will best meet your needs. Examples of details that they will need to know include the type, size, condition and location of surface that you plan to grind, as well as the type, thickness and age of the coatings applied to that surface. This information will help determine which variation of the following grinder attributes that you will need.
- Power source. Rental grinders can run on electricity, gasoline or propane. When you do grinding inside and have access to electricity, an electric model of grinder often works best. Keep in mind that some of the industrial grinders require 230V of electricity. Use gas-powered grinders on only outside surfaces. Propane grinders also offer more freedom of use since they do not require electricity.
- Single or multiple disc. Some rental grinders feature only one cutting disc, while other designs have two to four cutting discs. Multiple discs allow you to grind a wider area in one pass, which aids in grinding a large surface. Counter rotating discs make controlling the grinder easier because it keeps it from pulling to one side or the other.
- Wet grinding feature. Rental grinders designed for wet grinding include a water tank. Wet grinding helps to control dust. One disadvantage of wet grinding is that depending upon what material you remove, you could create a hazardous waste that requires you to dispose of it in a special manner. When wet grinding, avoid using excess water.
- Vacuum capabilities. Some rental grinders come with built-in dust collection systems. Other grinders allow you to attach a vacuum to them for dust collecting. Having a vacuum capability on a grinder lessens the amount of dust in the air that you breathe and keeps the work area cleaner. Make sure to rent a grinder that accommodates a vacuum if you expect the grinding to create a lot of dust.
- Accessories. Rental stores usually carry a variety of accessories — for rent or purchase — that you will need to complete your grinding work. These accessories include grinding discs, cup wheels, polishing pads and inserts. Diamond segments or plugs, carbide blocks or cutters, grinding stones, scarifier attachments and wire brushes make up several of the types of inserts possible.
Best practices
Before you use this equipment, please review the tips below and read all manufacturer warnings and instructions. Your local, ARA-affiliated rental store professional can provide you with complete instructions.
- Read all manufacturer warnings and instructions prior to using your rented grinder.
- Follow safe lifting practices when loading and unloading rented grinder.
- Properly secure rented grinder for transport.
- Wear appropriate personal protective equipment.
- Never wear loose clothing or jewelry that can catch on the rented grinder during use.
- Connect rented, electric grinder to a grounded outlet.
- Ensure feet stay clear of the rented grinder’s path during operation.
- Keep onlookers at an appropriate distance from the worksite.
- Check and, if needed, service fluid levels in rented, gas-powered grinders before use.
- Select a disc and inserts for the rented grinder that suits your intended application. Make sure to secure it to the rented grinder properly.
- Follow manufacturer’s recommendations for starting and shutting off the rented grinder.
- Use both hands when using the rented grinder.
- Work the grinder from side to side in an irregular pattern for even grinding.
- Do not exert physical strength against the rented grinder. Instead, guide the grinder and let it do the work.
- Do not let the rented grinder remain in one spot for very long while in use.
Contact your local, ARA-affiliated, rental store for information on available rental products and services to meet your concrete planer, grinder and scarifier needs. To locate the rental store nearest you, use the Rental Store Quick Locator above.