9 Common Grinding and Polishing Mistakes You Could be Making. Concrete grinding pads

12.05.2023 Malomeena common, grinding, making, mistakes, polishing

Common Grinding and Polishing Mistakes You Could be Making

Surface Preparation and concrete polishing is a competitive industry and the ability to achieve quality outcomes is essential for getting your projects noticed. This blog will touch on the 9 most common grinding and polishing mistakes and why it’s important to correct them.

MISTAKE 1; Not properly managing customer expectations

This may not seem like something that is overly important but in reality it’s incredibly important. Every customer has a vision of how they want the floor to look upon completion- sometimes it’s achievable but not always, so it is important to effectively manage customer expectations. This is often what contractors new to polishing and grinding find most difficult.

It is so important to properly educate your customer on what is a reasonable expectation for their floor, because every floor is different and has its own “personality” so to speak.

Here are some potential topics that should be covered before work begins…

If removing VCT before polishing, you will most likely see a “ghost shadow” of the VCT that will NEVER go away no matter how much grinding you do- and you won’t see it until the polishing part of the job.
Be aware of hidden imperfections like spalling, trenches etc.
Never promise a consistent monolithic floor (all salt pepper or all cream finish) promise the opposite, because you will have inconsistencies, cracks, spalling and the like. It is simply the personality of the floor and that is what polished concrete is. If the end user wants a more consistent floor finish, then possibly an overlayment will be required to get the floor to the desired finish

Mistake 2: Selecting the incorrect bond for the concrete you’re working with.

Once you understand how metal bond diamond tooling works, you can use the general rule of thumb when selecting the tooling for your job.

The “rule of thumb” is: soft concrete requires hard bond diamonds and hard concrete needs soft bond diamonds;

Metal Bond Tooling Guide:For Matching the Correct Diamond Bond Hardness to Concrete Hardness.

Very Hard Concrete (6,000-8,000 PSI). Extra Soft Bond Diamonds

Hard Concrete (5,000-6,000 PSI) Soft Extra Soft Bond Diamonds

Medium Concrete (3,500 – 5,000 PSI ) Medium Bond Diamonds

Soft Concrete (3,500 PSI and under) Hard Bond Diamonds

Soft Concrete = Hard Bond Diamonds
Medium Concrete = Medium Bond Diamonds
Hard Concrete = Soft Bond Diamonds
Very Hard Concrete = Extra Soft Diamonds

A major mistake contractors make, is selecting the incorrect bond for the concrete hardness and doing so will result in two outcomes…

The diamonds do not cut- often due to heating up and glazing over. (This happens mostly on hard concrete.)
You will wear out your tooling prematurely

Either way, you end up wasting your time, and money, and your results will suffer.

Mistake 3: Running the grinder unnecessarily Fast

A common mistake an operator can make when feeling under pressure, is running the grinder at an unnecessarily fast speed.

We tend to see this happening when an operator wants a faster production rate and will turn up the speed of the grinder in an effort to accomplish more in less time. However, this increased speed can overheat and “glaze over” your diamonds (especially on hard concrete) which prevents them from cutting properly, or at all (as mentioned earlier).

To give you an example, our Predator grinder/polishers run a maxim drum speed of 1,200 rpm when the dial set at 10 (full power). Although it can go 1,200 rpm if need be, generally it’s recommended to set the dial around 4.5-5.5 which runs the drum at approximately 600rpm. An operator can then adjust up a little or down a little to get the best performance.

Finding the right speed is important but speed alone doesn’t necessarily equate to better production rates.

MISTAKE 4, NOT UNDERSTANDING DOWNWARD PRESSURE

Ultimately, greater downward pressure = faster grinding

There are two ways of achieving this: A heavier machine will obviously give more head pressure but, so do different diamond options;

Single bar Double bar Single round Double round

If you are operating a smaller machine (like the alpha 9″, DFG280 11″, p550y P-2400 for example) a Single Rectangle or single round will give more down pressure because you have double the square inch pressure, compared to a double round or rectangle; allowing it to cut faster. The opposite is true of the larger machines where a double segment will offer better performance because it is grinding a larger space at one time.

Mistake 5: Going for the lowest price diamonds… simply because of the price

Although sometimes price isn’t always an indicator of quality (or lack thereof) when it comes to diamond tooling, it’s important to make sure that price isn’t your only criteria of consideration for purchase.

Poor quality diamonds wear faster, and inconsistently. They can scratch floors, and generally perform poorly, usually with limited or no support from the vendor.

Buy from a trusted vendor willing to stand behind their products. This will save you time and money in the long run.

Mistake 6: Not Inspecting your floor before starting

A metal bond diamond will grind and polish almost anything from steel, brass, glass, etc. AS LONG AS, the material is not “above grade” (raised above the floor surface).

Make sure you inspect the floors for anything above grade and either cut off, hand grind to level, or smack with a hammer to knock below grade. Once you’ve eliminated the above grade issues, you can grind it along with the concrete resulting in an interesting detail that adds to the personality of the floor. If you DO NOT inspect the floor and deal with the parts above grade before you begin grinding, you will most likely knock your diamond segment off and can do a lot of damage to your machine.

Mistake 7: Not Understanding the process needed for the Desired outcome

Here are a couple of questions and cautions for determining what your starting diamond will be…

What finish am I trying to achieve? i.e. Cream Polish? Salt Pepper Finish? Heavy Aggregate exposure?
What is on the floor now that must be removed before the polishing process can begin? Like epoxy coatings, VCT, Ceramic Tile, etc.

Here are some important things to be aware of…

Most polishing will start with a 40G metal bond diamond to expose the salt Pepper or aggregate.
If doing a cream polish you will almost NEVER start with a metal bond diamond as it will remove the cream, and once it’s gone… it’s gone forever.
If removing material like epoxy flooring before the polishing process, do not succumb to the temptation to use a more aggressive diamond like a PCD as it will make deep scratches that are extremely difficult, if not impossible, to remove.
When you’re not sure what diamond to start with, err on the side of caution and start with a less aggressive diamond, because you can always drop back to a more aggressive diamond, if need be.

Mistake 8: Not Removing stubborn scratches immediately

When polishing a floor, you must keep an eye on the finish you’re producing as you go. If you see faint scratches starting to appear you must remove them immediately, rather than “hope” the problem will cure itself… because it won’t. it will only continue to manifest as you polish up the floor.

For instance, if you are running a 100G resin bond diamond and you start to see scratches, do not think your next step, with 200G resins, will remove them. You must remove them with the 100G or if necessary fall back to a more aggressive diamond like a 50G or 30G resin before you move onto the next step.

To reiterate: Remove the problem scratches as soon as you see them. Do NOT leave them and hope they go away… because they won’t and your results will suffer because of it.

Mistake 9: Not pREFORMING YOUR WORK IN COMPLIANCE WITH GOVERNMENT REGULATIONS.

There are regulations regarding cutting concrete because of the health concerns related to silica dust in the concrete grindings that can be released into the air during the grinding process and must be captured a couple of different ways, the first being a dust collection system (a vacuum to the layman LOL) but, and this is critical, not just any vacuum but a HEPA FILTER system, these take 99.97 percent of the friable material out of the air making it safe to work and protects you from a really big fine in most of the world!

the second is WATER. you can grind wet and this keeps the silica-containing dust captured in the concrete slurry. it is important to note that that slurry must be disposed of correctly as it is considered hazardous waste in most countries.

Concrete grinding and polishing can really be a profitable and satisfying profession when you stand back and look at a well-polished floor but can be a frustrating profession when things do not go well, hopefully the information covered in the article helps you keep projects interesting and profitable.

Choosing the Right Diamond Grit Size for Your Concrete Grinding Job

Concrete grinding is an essential step in many construction and renovation projects. It helps to level uneven surfaces, remove imperfections, and prepare the concrete for coatings or polishing. One critical factor in achieving a successful concrete grinding job is choosing the right diamond grit size.

Diamond grit size refers to the size of the diamond particles embedded in the grinding tools. It plays a crucial role in determining the efficiency, speed, and quality of the grinding process. In this article, we will explore the different diamond grit sizes available and guide you on how to choose the right diamond grit size for your concrete grinding job.

The Importance of Selecting the Correct Diamond Grit Size

Diamond tools used in hard concrete grinding have a wide range of grit sizes. Diamond grinding is the process of using a diamond abrasive to remove material from a hard surface. The diamond abrasives are bonded to a metal or resin matrix, which is then attached to a grinding machine or other equipment.

The diamond grit size refers to the size of the individual diamond particles on the abrasive disk. The size of the diamond grit is measured in microns, with smaller micron numbers indicating larger diamond particles.

Choosing the correct diamond grit size when grinding concrete is important because it affects how much material is removed from the surface and how quickly the work is completed.

A larger grit size will remove more material but will also leave a rougher surface, while a smaller grit size will remove less material but will leave a smoother surface. It’s important to choose the right grit size for your specific job to ensure that you achieve the desired finish without damaging the surface or your equipment.

Understanding Diamond Grit Sizes

Diamond grit sizes are indicated by numbers that represent the size of the diamond particles in the grinding tool. The lower the number, the larger the diamond particles, and the coarser the grit size.

Conversely, the higher the number, the smaller the diamond particles, and the finer the grit size. Diamond grit sizes typically range from 16 to 3000, with 16 being the coarsest and 3000 being the finest.

Coarse Grit (16-40)

Coarse diamond grit sizes such as 16-40 are used for aggressive grinding and removal of thick coatings, adhesives, and uneven surfaces. They are typically used in the initial stages of concrete grinding when the surface is severely damaged or needs to be leveled.

Medium Grit (40-80)

Medium diamond grit sizes like 40-80 are used for general grinding and removal of moderate coatings, adhesives, and imperfections. They are commonly used in the intermediate stages of concrete grinding to refine the surface after the initial coarse grinding.

Fine Grit (100-200)

Fine diamond grit sizes such as 100-200 are used for fine grinding and polishing of the concrete surface. They are typically used in the final stages of concrete grinding to achieve a smooth and polished finish.

Extra Fine Grit (400-3000)

Extra fine diamond grit sizes like 400-3000 are used for fine polishing and honing of the concrete surface. They are used to achieve a high gloss and mirror-like finish on the concrete surface.

Factors to Consider When Choosing Diamond Grit Size

Choosing the right diamond grit size for your concrete grinding job depends on several factors. It’s crucial to consider these factors to ensure that you achieve the desired results efficiently and effectively. Here are some factors to consider when choosing diamond grit size:

Surface Condition

The condition of the concrete surface you are grinding is a crucial factor in determining the appropriate diamond grit size. If the surface is heavily damaged, has thick coatings, or uneven patches, a coarse diamond grit size such as 16-40 may be required for aggressive grinding and removal.

For moderately damaged surfaces, a medium grit size like 40-80 may be suitable for general grinding and surface refinement. If the surface is in relatively good condition and requires polishing, a fine or extra fine diamond grit size may be appropriate. For soft concrete, soft bond is preferred.

Grinding Goals

Diamond tooling is available in various grit sizes, and each one is suitable for different grinding goals. The goals of your concrete grinding job also play a role in choosing the right diamond grit size.

If you are aiming to remove coatings or adhesives quickly, a coarse grit size may be necessary. If you are looking for a polished finish, a fine or extra fine grit size may be needed. Consider the end result you want to achieve and choose the diamond grit size accordingly.

Equipment and Speed

The type of grinding equipment and the speed at which you are grinding also influence the diamond grit size selection. Different grinding machines have different capabilities, and their performance can vary with different diamond grit sizes.

polishing pads

common, grinding, polishing, mistakes, making

Coarse grits are typically used with high-speed grinders, while finer grits are used with low-speed grinders. It’s essential to consult the manufacturer’s guidelines to ensure that you select the right diamond grit size for your equipment.

A diamond grinding cup wheel with a finer grit size can produce a smoother finish on the concrete surface than a coarse grit size.

Common Mistakes to Avoid When Selecting Diamond Grit Size

Concrete polishing and grinding is a delicate process, and selecting the wrong diamond grit size can lead to a range of mistakes.

One of the most common mistakes people make when selecting diamond grit size is assuming that a higher grit number is always better. However, this is not always the case.

While a high grit number can produce a very smooth surface, it may not be the best choice for all applications. For example, if you need to remove a lot of material quickly, a lower grit number may be more appropriate.

Another mistake is not considering the hardness of the surface you are grinding. Harder surfaces require a higher diamond grit number to effectively remove material.

If you use too low of a grit number on a hard surface, the diamond particles will wear down quickly, reducing the effectiveness of the abrasive disk and causing damage to your equipment.

How to Determine the Diamond Grit Size You Need

The diamond grit size you need for your concrete grinders will depend on several factors, including the type of surface you are grinding, the amount of material you need to remove, and the desired finish.

Here are some general guidelines to follow:

For heavy material removal, use a lower diamond grit number, such as 16-40.
For moderate material removal, use a medium diamond grit number, such as 70-120.
For light material removal and a smooth finish, use a higher diamond grit number, such as 200-400.

However, keep in mind that these are just general guidelines, and the specific diamond grit size you need will depend on the unique characteristics of your job.

Tips for Grinding Smarter, Not Harder

Now that you understand the importance of selecting the correct diamond grit size, here are some additional tips for grinding smarter, not harder:

Use the right equipment. Make sure you have the right grinder. disk, and other equipment for the job.
Keep the disk clean. Clean the diamond abrasive disk regularly to prevent clogging and ensure maximum effectiveness. The diamond cup wheel should spin freely and not be overworked.
Use a steady hand. Keep the grinder steady and move it in a smooth, even motion to prevent damage to the surface and your equipment.
Use water. Water can help control dust and prevent the surface from overheating, which can cause damage to the diamond abrasive disk.

Techniques for Using Diamond Grit Effectively

To use diamond grit effectively for your concrete floor. it’s important to follow the right techniques. Here are some tips to keep in mind:

Start with a lower diamond grit number and work your way up to higher grits. This will help you achieve a smoother surface and prevent damage to your equipment.
Use overlapping passes. Make sure each pass overlaps the previous one by about one-third to ensure even material removal.
Keep the disk level. Make sure the diamond abrasive disk is level with the surface being ground to prevent uneven material removal and damage to your equipment.
Use a consistent speed. Keep the grinder at a consistent speed to prevent damage to the surface and your equipment.

Tools and Equipment for Grinding with Diamond Grit

To effectively grind with diamond grit, you’ll need the right tools and equipment. Here are some things to consider:

Grinder: A high-quality grinder is essential for effective diamond grinding. Look for a grinder with a variable speed control and a dust collection system.
Diamond abrasive disk: Choose a high-quality diamond abrasive disk with the right grit size for your job.
Dust collection system: A dust collection system is important for controlling dust and preventing damage to your equipment.
Safety gear: Wear safety gear. including eye protection, ear protection, and a dust mask, to protect yourself from dust and debris.

Conclusion

In conclusion, selecting the correct diamond grit size is crucial to grinding smarter, not harder. By choosing the right grit size for your specific job, you can maximize efficiency, achieve the desired finish, and minimize damage to your equipment.

Avoid common mistakes, follow the right techniques, and use the right tools and equipment to ensure a successful grinding project. With these tips in mind, you’ll be able to tackle any grinding job with confidence and ease.

HD-Resin Pads

A versatile polishing tool that can be used dry or wet on both soft and hard concrete.

The HD Resin pads are suitable for use with heavier grinders (25″ and up).
Grit size range from 30 to 3000 grit.
Offered with velcro backing in 3″ and 4″, and as 9″ and 13″ Quick Change Rings. Use the rings with security plates #A85.00.00 for 9″ rings, and #A84.00.00 for 13″ rings.
Recommended RPM: 200 400 Grit tools – 650-750 rpm; 800 Grit up – 800-1100 rpm for electric machines; for propane machines – 2100-2600 rpm.

HD-Resin tools are offered in Quick Change Ring style in 9″, 10.63″ and 13″.

HD-Resin pucks with velcro backing are offered in 3″ size.

Find a LAVINA Distributor

Get in Touch

Hours: 8:30am-5:00 pm EST(US) 1-706-362-4813800-987-8403, ext. 133alex@superabrasive.us

9411 Jackson Trail RoadHoschton, GA 30548, USAtel.: 706 658 1122toll-free: 800 987 8403fax: 706 658 0357info@superabrasive.us

Rabotnicheska Str. #2A6140 Krun, obl. Stara Zagora, Bulgariatel.: 359 431 64477fax: 359 431 64466factory@superabrasive.com

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Grinding Concrete with a 7 Grinder Wheel

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