The Ultimate Guide To Concrete Grinding Diamonds

What Diamonds To Use In Every Situation — Without Guesswork

Concrete Grinding diamonds are not trial-and-error tools. They are precision cutting systems controlled by three variables:

1) Bond Hardness (Soft → Medium → Hard → Extra-Hard)
2) Segment Type (Tooling Style)
3) Grit Size

Get even one wrong and you will:

– Lose time on site
– Burn diamonds
– Damage slabs
– Glaze tooling

This page gives you a simple, repeatable system to choose the correct tooling — fast and confidently.

The Three Controls That Decide Everything

1) Bond Hardness
Controls how fast the metal wears and how consistently fresh diamonds are exposed.

2) Segment Type
Controls aggression, scratch pattern, and how risky the tooling is on softer slabs.

3) Grit Size
Controls how much material is removed and how clean the finish is at each stage.

Bond Hardness

– Hard Concrete Needs Soft Bond Diamonds
– Soft Concrete Needs Hard Bond Diamonds

This rule overrides:

– “What you’ve always used”
– Segment shape
– Grit size
– Brand

If tooling is glazing, the issue is almost always bond selection or RPM.

Soft Bond Diamonds – For Very Hard, Dense Concrete

Soft bond diamonds should be used when:

– 40+ MPa concrete
– Old dense commercial slabs
– Power-trowelled warehouse floors
– Tilt-panel construction
– Burnished or laser-levelled slabs
– Polished concrete removal
– Any slab that looks shiny when exposed

Why They Work:

Soft bonds wear quickly, continuously exposing fresh diamonds and preventing glazing.

Signs You Need Soft Bond:

– The machine feels like it’s floating
– Diamonds look shiny and smooth
– Grinder vibrates but doesn’t cut
– Little or no dust

Common Pairings:

– Soft-bond arrow segments (coatings)
– Soft-bond double bar (flattening)
– Soft-bond 30/40 → 60/80 (prep)

Medium Bond Diamonds – Safe Starting Point

Use When:

– Concrete hardness is unknown
– Average commercial floors
– Screeds and toppings
– New construction
– Residential slabs

Best Practice:

– Start medium
– If they glaze → go softer
– If they burn fast → go harder

Hard Bond Diamonds – For Soft Or Abrasive Concrete

Use When:

– Poor-quality residential pours
– Moisture-damaged concrete
– Chalky or sandy slabs
– Lightweight concrete
– Low-MPa concrete
– External slabs

Why They Work:
They slowly wear on abrasive slabs and prevent diamonds from disappearing rapidly.

Red Flags Your Bond Is Too Soft:

– Segment edges are rounded instantly
– Diamonds gone in under 30 minutes
– Excessive dust or slurry

Extra-Hard Bond Diamonds – Extreme Conditions Only

Use When:

– Screeds
– Weak toppings
– Magnesite residue
– Ultra-soft concrete
– Asphalt contamination
– Extremely abrasive glue beds

Pro Tip:
If hard bond still wears fast → go extra-hard.

Segment Types – Aggression Vs Control

Arrow / Triangle Segments – Maximum Aggression

Use For:

– Thick coatings
– Glue removal
– Epoxy
– Waterproofing
– Vinyl adhesive
– Paint
– High spots

Avoid When:

– Finishing
– Soft slabs (high gouge risk)

Double Bar / Rectangle Segments – The Workhorse

Use For:

– Large planetary grinders
– Slab flattening
– Heavy preparation
– Long production runs
– CSP-2 to CSP-3 outcomes

Most commonly used segment style on site.

Single Bar / Oval Segments

Use For:

– Smaller grinders
– Tight spaces
– Residential jobs
– Faster bite with lighter machines

Round / Button Segments

Use For:

– Smoother grinding
– Scratch control
– Reducing chatter
– Follow-up after aggressive metals

T-Segments – Edge Tooling

Use For:

– Walls, columns, corners
– Tight perimeters
– Controlled edge work without gouging

PCD Diamonds – Coating Destruction Tools

PCD Use For:

– Thick epoxy
– Urethanes
– Vinyl glue beds
– Carpet adhesive
– Waterproof membranes
– Rubber residue
– Bitumen
– Multiple coating layers

What PCDs Do:
They rip and shear coatings — they do not grind like metal diamonds.

Critical Rules:

– Never use PCDs alone on bare concrete
– Always follow with metal diamonds
– Expect CSP-4+ initially

Common Combos:

– PCD + sacrificial diamond
– PCD → 16/20 metal
– PCD → bush hammer (only if required)

Bush Hammers – Last-Resort Tooling

Bush hammers are problem-solvers, not standard grinding tools.

Use Only When:

– All diamond tooling has failed
– Extremely thick or hard coatings
– Industrial membranes
– Several millimetres of concrete must be removed
– Severe laitance
– Decorative texture exposure
– External anti-slip finishes

What They Do:
They impact-fracture the surface. They destroy — not grind.

Why They’re Avoided:

– Extremely aggressive texture
– Heavy follow-up grinding
– Increased vibration
– Accelerated machine wear

Correct Workflow:

1. Correct bond diamonds

2. RPM adjustment

3. Sand method

4. PCDs

5. Bush hammer only if unavoidable

6. Follow with metal diamonds

Steel Wire Brush Attachments – Surface Cleaning Only (Not Grinding)

Steel Wire Brush Attachments – What They’re Actually For

Steel wire brush attachments are not grinding tools and are not a replacement for diamonds or PCDs.

They do not:

Flatten slabs
Remove concrete
Create CSP profiles
Replace metal diamonds

They only:

Break surface films
Disrupt soft residues
Clean contamination off the slab surface

Use Steel Wire Brushes For:

– Light paint overspray
– Thin curing compounds
– Soft laitance
– Powdery or chalky surface residue
– Pre-cleaning before diamonds
– Cleaning expansion joints or edges

Do NOT Use Steel Wire Brushes For:

– Thick epoxy
– Vinyl glue beds
– Waterproof membranes
– Level correction
– Stock removal
– Slab flattening

If concrete needs to be removed → you’re already in diamond or PCD territory.

Grit Progression – From Destruction To Finish

Coatings / Glue / Membranes → PCD / Bush Hammer
Heavy Stock Removal → 16/20
Main Prep (CSP-2 → CSP-3) → 30/40
Scratch Refinement → 60/80
Smoothing / Transition → 120+

Real-World Scenarios

Residential Garage (Unknown Slab)
Medium bond double bar → 30/40 → 60/80

Commercial Epoxy Removal
PCDs → 16/20 soft bond → finish 30/40

Hard Warehouse Slab
Soft bond double bar → 30/40 → 60/80

Soft Chalky Concrete
Hard or extra-hard bond → round segments

Vinyl Glue Nightmare
PCD + sacrificial → bush hammer only if unrecoverable → soft bond metals

Screed Removal
Extra-hard bond → arrow segments → low RPM

Slab Flattening
Double bar segments → correct bond → cross-hatch passes

Techniques That Make Grinding Faster (Without Burning Diamonds)

The Sand Method

Light sprinkle of coarse sand
Grind slowly
Let sand abrade the bond
Never flood
If sand works → bond was too hard

Reduce RPM Before Changing Diamonds

High RPM polishes instead of cutting.
Lower RPM = more bite and less glazing.

Cross-Hatching Passes

North–south → east–west
Improves flatness and scratch control.

Add Weight Strategically

Only on confirmed hard slabs using approved weight kits.

Controlled Moisture

– Reduces heat
– Prevents glue smearing
– Improves cutting

Never flood unless tooling is wet-rated.

On-Site Diamond Troubleshooting

Grinder Not Cutting

– No dust → glazed
– Reduce RPM
– Sand method
– Softer bond
– Cross-hatch
– PCDs
– Bush hammer (last resort)

Diamonds Wearing Too Fast

– Concrete too soft/abrasive
– Move to hard → extra-hard bond
– Avoid arrows

Bouncing Or Chatter

– Less aggressive segments
– Reduce RPM
– Increase overlap
– Switch to round segments

Coating Smearing

– Stop immediately
– Switch to PCDs
– Lower RPM
– Light moisture, if approved

Deep Scratches

– Remove arrows / PCDs
– 16/20 → 30/40
– Cross-hatch
– Refine 60/80

Nothing Works

– Bush hammer
– Then metal diamonds
– Expect extra passes

If You Remember Nothing Else

Bond selection beats brand
RPM kills more diamonds than concrete
Hard slabs lie — they look easy but aren’t
PCDs solve coatings, not concrete
Bush hammers cost time unless unavoidable
Diamonds don’t fail — decisions do

Still Unsure? Talk To A Concrete Grinding Expert

If you’ve read this far and still aren’t sure which diamonds you need or how to set up your grinder, that’s absolutely fine — this stuff can be tricky. Give us a call on 0424 408 330 or fill out our quick quote form. We’ll walk you through it and make sure your job gets done right the first time.

Concrete Polishing Diamonds — When And How To Use Them

This guide focuses primarily on concrete grinding diamonds because grinding is where material removal, surface correction, and tooling mistakes cost the most time and money.

However, many concrete jobs do not stop at grinding alone. In polished concrete systems, grinding diamonds are only the first stage — followed by concrete polishing diamonds, which refine and finish the surface.

Understanding when to stop grinding and when to start polishing is critical.

What Are Concrete Polishing Diamonds?

Concrete polishing diamonds are finishing tools, not removal tools.

They are designed to:

– Refine scratch patterns left by grinding
– Smooth the surface progressively
– Increase surface clarity and sheen
– Prepare concrete for densification and final polishing

Unlike grinding diamonds, polishing diamonds are typically:

– Resin-bond or hybrid-bond
– Used at higher grit levels
– Designed to refine, not flatten

They do not correct slab levels, remove heavy coatings, or fix structural surface issues.

When To Use Concrete Polishing Diamonds

You should only move to polishing diamonds after the slab has already been:

– Flattened
– Leveled
– Stripped of coatings or contaminants
– Taken through the correct coarse grinding stages

Polishing diamonds is used when:

– The slab is already flat and consistent
– All coatings, glue, membranes, and defects are removed
– You are transitioning from cutting concrete to refining concrete

If grinding diamonds is still required to fix the surface, polishing diamonds is being used too early.

How Polishing Diamonds Differ From Grinding Diamonds

Primary Purpose
Concrete Grinding – Material removal & surface correction
Concrete Polishing – Surface refinement & finish

Typical Bond
Concrete Grinding – Metal bond
Concrete Polishing – Resin or hybrid bond

Grit Range
Concrete Grinding – Coarse to medium (6–80 grit)
Concrete Polishing – Fine to ultra-fine (100–3000+)

Cutting Action
Concrete Grinding – Aggressive cutting
Concrete Polishing – Controlled abrasion

Result
Concrete Grinding – Flat but scratched surface
Concrete Polishing – Smooth, refined, glossy surface

They are not interchangeable.

Typical Grinding-To-Polishing Progression

A simplified real-world sequence looks like this:

1. Coarse Grinding Diamonds
Used to remove coatings, flatten high spots, and correct the slab

2. Intermediate Grinding Diamonds
Used to reduce deep scratches and prepare the surface

3. Transition / Hybrid Tooling (Optional)
Bridges the gap between metal and resin tooling

4. Polishing Diamonds
Used in progressive grits to refine and polish the concrete

Skipping steps or switching to polishing diamonds too early leads to:

– Visible swirl marks
– Uneven sheen
– Burned resin pads
– A finish that will never “clean up”

Critical Rule Most People Get Wrong

Polishing diamonds does not fix grinding mistakes

If:

– The slab isn’t flat
– Deep scratches remain
– Coatings weren’t fully removed

Then polishing diamonds will only highlight those problems, not remove them.

That is why grinding diamond selection — bond hardness, segment type, and grit — always comes first.