When renovating a home, one of the best surfaces you can select is right under your nose, yet you may overlook it. From concrete countertops to concrete floors, you can add a unique surface and finish that is more cost-effective than many other options.
Much of the issue comes from polishing; many homeowners may not be sure they can tackle this task. The good thing is, concrete polishing can be more accessible than you imagine. By the end of this guide, you’ll learn more about how to sand concrete.
You will also see how to get the best finish on sanded concrete floors or a highly polished surface on your concrete countertop. (Learn How Many Wheelbarrows In A Yard Of Concrete)
Can You Polish Concrete Yourself?
To polish concrete yourself, you’ll need a concrete grinder. Unless you know someone, you’ll need to rent one. Besides this, you’ll need a full range of grinding disks and polishing pads ranging from 30 to 3,000 grit for grinding concrete to the best finish.
Polishing concrete is like sanding a hardwood floor, yet the difference with your concrete being you’ll go over the concrete surface more with your grinder. If you are doing a concrete countertop, it can mean lots of passes depending on the type of grinder you use. (Learn How To Get Rid Of Sticky Residue)
After using the rough grit, you’ll work to finer and move to a polishing pad. The surface will soon feel smooth, and then you’ll seal the surface with a concrete sealer to make it appear stone-like, which shines without using floor wax.
What Can I Use to Polish Concrete?
Concrete is a mix of cement, aggregate, sand, and water. Cement is brittle, although the mixture becomes strong when you add sand or rocks. Cement acts like glue to fill small gaps in the aggregate and sand. When casting concrete, the cement paste creates a layer on the surface that is one solid color with slight variations. This is a cast finish. You can remove this with light polishing, where you expose the sand in the mix, called a light polish.
Harder polishing exposes aggregate and produces a ground finish. You can do this to hand polish concrete countertops or floors, and all that differs is equipment. Polishing will be done using variable speed concrete polisher and diamond sanding discs. The polisher can be water fed to cool the pads and stop dust.
Can You Use Regular Sandpaper to Polish Concrete?
If you are polishing a small concrete surface, such as a concrete countertop, there is no way you can use regular sandpaper. The construction of this won’t stand up to the rigors the surfaces face from concrete grinders. Diamond pads are what you will use on your countertop or floor. Shapes and sizes differ depending on what you want to grind.
Diamond is one of the hardest materials, and conventional sandpaper is nothing more than sand. You can get sander discs that fit your grinder tools, yet a concrete sander is much more extensive when used for floor work. (Find the Best Saws for Cutting Metal)
How Do You Make Concrete Shine?
Here’s each step you need to polish your concrete surfaces. It doesn’t matter if you are doing a concrete floor or a countertop. The process is the same, and it’s just equipment that may differ. This example will use concrete polishing for a countertop.
Polishing concrete countertops isn’t dangerous, yet water and electricity don’t mix. Make sure to wear rubber gloves to insulate yourself. Besides this, also wear a particle mask when dry grinding, as concrete dust can be caustic.
Grinding vs. Polishing
Grinding is the roughest way to flatten concrete surfaces. Polishing is you take the ground surface to a smoother and shiny finish.
Variable Speed Polisher
A variable-speed wet polisher can be the most versatile tool for decorative concrete work. Water feed lines are like the best gardening hose that feeds water to stop dust or cool polisher bearings and discs.
Kinds of Polishing Pads
- Soft Pads: You use a rubber backer. You screw on the polisher. You’ll find these better for beginners, and they can polish contoured surfaces when using a water-fed concrete polisher.
- Rigid Pads: With these, you use a quick-release mechanism on the polisher. Rigid pad polish is faster, yet they can gouge into the surface of your pads, not flat. Also, these are used with a water-fed concrete polisher.
- Wet & Dry Pads: Again, using a quick-release mechanism, they are safe to use on a high-speed angle grinder.
You need to visualize the results before you start the polishing process. You can remove more, but you can’t add it back.
- Wear rubber gloves and possibly an apron and rubber boots
- Elevate the piece if possible
- Polish outdoors or indoors using a polishing table if possible
For your ground finish, sand concrete with a low-grit pad, usually around 60 grit. Polish evenly until a uniform amount of aggregate is exposed on the wet concrete before moving to the next pad.
To light polish, start at 200 grit. Tape off areas you don’t want polished.
How to Polish
Here’s an essential step-by-step guide to polishing
- Turn on your water feed
- Raise your polisher over the surface and turn it on
- Lower your polisher to the concrete. Let the tool’s weight work, and keep the pad as flat as possible.
- Move across the entire surface evenly, in circular motions, and never start or stop the same area’s polishing process.
- If you have a large area to polish, break it down into smaller sections
- Move to the next pad after sanding the surface uniformly
Use Slurry to Fill Holes
Once you reach halfway and use around 400-grit, you can fill holes. Apply slurry, a material made of cement paste, pigment, and water. Let it dry for 24 hours, and resume sanding and polishing your countertop.
- Remove excess slurry through polishing and using higher grit pads starting at 400 grit upward.
- To end, you need a sealer for the entire surface, as this keeps your countertop looking nice and preserves the polished finish.
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