Concrete polishing is a technique by which you smooth the top surface of the concrete. A polishing tool uses mechanical power to cut or refine the surface of the concrete until it has the right finish. A newly polished surface will do wonders for any construction site. It is a cost-effective solution that adds to the beauty of the site exponentially. Polished concrete has a very reflective and shiny appearance. Go through the article once to know all about the concrete polishing tools and master the technique.
- Polishing tools:
- How to polish concrete? The step by step guide
- 1. Clean and patch the surface
- 2. Smooth the Surface with a Grinder
- 3. Get a set of metal-bonded diamond discs
- 4. Grind the surface
- 5. Repeat the grinding process with various discs
- 6. Spray on a densifier
- 7. Make the final grinding pass
- 8. Vacuum the concrete
- 9. Buff and Seal the Surface
- 10. Burnish the surface
- 11. Wait
- Frequently Asked Questions
To polish flawlessly, you need the right know-how and required equipment. Here is the list of tools that you must be familiar with
Grinders and polishers:
It is not only important to have the best quality grinder but it should be of proper weight and RPW. They come in a different range of sizes and may vary up to 36 inches. You can choose the size of the grinder as per the area that you need to polish. A grinder with higher RPM is usually required to polish the concrete in steps. If you have to polish floors, you must choose a diamond grinder equivalent to the HTC 800. In addition to this, the right cutter for the grinder is as important as the grinder itself. There are two kinds of pad tools that you must have.
Metal bond tools: It is used for both grinding and polishing hard while preparing concrete floors.
Resin tools: You can use these for polishing the surface.
Industrial floor vacuum:
One of the most convenient options available in construction is the dry grinding and polishing system. However, it gives rise to a lot of dust. An industrial vacuum cleaner helps to clean up all the dust and fragments left over.
Hardening and compacting agents:
While polishing concrete, it is suggested to apply a hardener to harden the concrete and make it denser. The hardening agent makes the concrete hard and it gets easy to polish. The compacting agent not only makes the concrete floor thick but also helps it to become water-resistant and stain-free. Moreover, hardening and compacting agents make the concrete shiny for a longer period.
Different Coloring Agents, Dyes, and Stains:
If you want to bring some vibrant tones to your floor, coloring agents are the right choice. With the help of different dyes and stains, you can get the floor color of your choice. Add the color to the unpoured concrete and later polish it smooth. You will have a beautiful colored floor as per your desired theme.
With the list of the good arsenal of concrete polishing tools at your disposal, you never have to turn down concrete finishing opportunities. You just need the right tools to do the task efficiently. The article covers all the important concrete polishing tools. However, the process of polishing is a bit tricky and needs experience with the tools. You can also contact us for any professional help. The website http://www.proconcretepolishingperth.com/ will connect you to our expert construction team.
How to polish concrete? The step by step guide
Polished concrete has a sophisticated and modern vibe and the polishing process improves its condition and strength. Should you want to polish concrete, keep in mind that you need to put some elbow grease and time into it. Polishing a concrete countertop is similar to polishing the floor, and our guide refers to the latter.
1. Clean and patch the surface
Use water, soap, and a bristle brush to clean the whole surface
Have some warm water with your regular household cleaner in a bucket and dip the bristle brush in the bucket. Scrub the concrete thoroughly and use clean water to rinse. Let it air dry.
For stubborn stains, you can use one of the following: ammonia, hydrogen peroxide, or TSP (trisodium phosphate). Do the cleaning as before and put on protective eyewear and gloves. Remember to ventilate the room and use a broom-style bristle brush with a handle for effortless cleaning.
Look for hazard spots and damage
Once the concrete is clean, you can examine it a lot more efficiently. See if there are large cracks or hazards, such as pieces of metal. Mark them with temporary paint so that you can manage them before you begin grinding. Hire a professional if repair work is too much for you.
Use a patch material/concrete filler to repair cracks
Remove any debris from inside the cracks with a wire brush. Use concrete crack filler for cracks up to 0.25in and a caulk gun to apply it. Squeeze the stuffing into the crack and smooth it with a paint scraper or your finger. If the cracks are wide, you should go with vinyl concrete patch material. A trowel is excellent at filling the crack with the patch material and smoothing the surface.
Allow the filler to cure entirely as stated in the package instructions. Once it’s cured, sweep up debris on the floor.
2. Smooth the Surface with a Grinder
Test the concrete
You have to test the concrete with a MOHS hardness pick before you rent the grinder. Select an important area of the concrete, hold the no.9 pick like a pencil, and use the same pressure as you would when drawing 2in pencil line on the surface. Take a look at the scratch and feel it. You have to try as many pick numbers as necessary (no8, no.7, etc.) until you get a pick that doesn’t leave scratches.
For example, if the no.6 doesn’t leave scratches, but the no.7 does, you can assume that your concrete has a MOHS (Measurement of Hardness Scale) rating of 6.5. The higher the number, the harder the concrete is.
When renting a concrete grinder, the set of grinding discs will vary according to strength: soft (5.5 and lower), medium (6.5), and hard (7.5 and higher).
3. Get a set of metal-bonded diamond discs
Get a concrete grinder with a set of grinding discs ranging between 40-grit and 3000-grit. Ideally, you should get on that matches soft, medium, or hard concrete. Also, get a specialized tool to grind concrete; a standard sander won’t do any good.
See that the grinding discs are metal-bonded diamond discs. Also, choose a grinder that you can effortlessly maneuver. You will pay around $1,000 per week to rent the grinder. If your concrete surface is small, you might get a cheaper job by hiring a professional instead of renting the grinder and doing it yourself.
Put on protective gear
Put on safety goggles, thick gloves, earplugs, and a dust mask before you use the grinder. The tool is loud, generates a lot of dust, and can pose a high risk of injuries when misused.
Also, wear work shoes with an adequate grip that prevent accidents caused by slipping, sliding, or falling over.
4. Grind the surface
Attach the disc and begin with a 40-grit grinding disc to remove stains, sealers, and other contaminants that didn’t wash away. Use an 80-grit disc if there aren’t any. Turn on the grinder and use back and forth in half circle moves. Take your time and make sure to work the surface as evenly as possible.
We recommend you begin from one corner and go your way out and toward the opposite corner. A low grit value means that the disc is coarse. For example, the 40-grit disc is coarser than the 80-grit model.
5. Repeat the grinding process with various discs
You need to go over the concrete with every disc in your set. 40-grit, 80-grit, 150-grit, 200-grit, and 400-grit is the standard order. Work perpendicular to the previous pass. You need to imagine a square concrete surface from above. If you passed from the top left to the bottom right corner, the following pass should start from the top right and bottom left corner.
The idea is that every pass with a new disc will buff away all scratches from the previous pass until you no longer get scratches.
6. Spray on a densifier
Apply the densifier (a liquid chemical hardener) according to the instructions. The densifier makes concrete less porous and reduces the risk of powdery dust on the surface. You need to apply it according to the hardness of the concrete.
For soft concrete, you should apply the densifier after the 80-grit disc, whereas medium concrete requires it after the 200-grit pass. Apply the densifier after the 400-grit disc on the hard concrete.
7. Make the final grinding pass
Work the whole concrete surface again and move one corner to the diagonally opposite one. Use the 3000-grit disc to start the polishing. Some users go straight to polishing, but using the 3000-grit disc will give the concrete a high-glossy finish.
8. Vacuum the concrete
Grinding concrete gives a lot of debris and dust. After using the last disc, use a wet-dry vacuum to remove as much dirt/debris as possible. Some grinders come with a built-in vacuum, but you should still use the vacuum for the best cleaning results.
9. Buff and Seal the Surface
Use a burnishing pad
Put on a burnishing pad on the grinder and follow the instruction. Turn on the tool and use the pad over the entire surface with the corner-to-corner method, half-circle. The pad will smooth out the concrete surface.
It’s possible to rent the burnishing pad while you rent the grinder with the discs. If not possible, rent a low-speed brush buffer.
Apply a concrete sealer
Select a water-based/ solvent-based concrete sealer and follow the manufacturer’s recommendations when applying it. You may have to fill a paint pan and use a paint roller to apply a thin coat over the surface. If your surface needs spraying, use a sprayer and apply an even and light coating over the concrete.
Sealers will protect the concrete against stains, dirt, and grease. Additionally, a glossy sealer will give the concrete an excellent luster. Keep in mind to apply the sealer only during dry conditions, when the temperature doesn’t go below 50F degrees.
Apply a second sealer coat
Let the sealer dry for two hours and check it out. If it’s still tacky, allow it another two hours. Spray on or roll on the second coat of sealer, but work in a perpendicular direction this time. The second coat should also be thin and even. Give it 2-4 hours to completely dry.
10. Burnish the surface
When the sealer is dry, you should pass over the surface with a buffer or a burnishing pad. Use a perpendicular direction from the previous pass. Take your time and cover the whole surface at an even pace. Your concrete should be smooth and lustrous when you’re done.
Let the final coat of sealer completely dry before you use the concrete surface. Typically, you will need to wait between 24 and 72 hours.
Frequently Asked Questions
What do you put on concrete to make it shine?
For a shiny surface on your concrete, you need to add a glossy sealer. The acrylic wax will also work as a protective coat. Epoxy and polyurethane sealers resist abrasion, stains, and high traffic, whereas water-based acrylic sealers are more accessible to apply and more affordable than epoxy sealers.
Is polished concrete waterproof?
Polished concrete offers a surface that resists damage from oil and chemical spills, and it’s slip and water-resistant. Since concrete is naturally a highly porous surface, it can be water-resistant is essential to have.
Can you polish any concrete floor?
Regardless of age, almost all structurally sound concrete floors allow polishing. Some exceptions do apply. For instance, new floors don’t need a unique mix to get good results like most concrete floors. However, the floor has to be in place at least 28 days before polishing so that proper curing takes place.
Are polished concrete floors easy to scratch?
Polished concrete flooring is solid and resilient and can take pressure from heavy foot traffic and equipment. As a result, the polished concrete floor is difficult to damage and almost impossible to scratch or chip.
Is there a perfect mix for polished concrete?
The typical concrete mix ratio is 5 to 1 to 5, sand, cement, and aggregate. Even if you get the proper balance, the kind of sand and aggregate you use will affect the final look of the floor. Therefore, you should always combine the ingredients so that the floor looks as planned.