How to Properly Sand Epoxy Resin (Without Losing Your Mind or Shine)

Your complete, no-fluff guide to sanding epoxy like a pro. 

If you've ever poured resin, stepped back to admire it, and then looked just a liiiiittle closer only to whisper "...why is it like that?" - don't worry. You're not alone. Even the best pours sometimes leave behind a few imperfections. A tiny bubble. A rogue piece of dust. Or you simply need another layer to finish it off and don't know what to do. 

That's where sanding comes in. 

Sanding is the unsung hero of the epoxy world. It's the step everyone wishes they could skip, but it's also the step that transforms your projects. The difference between a finish that merely exists and one that turns heads is often just a few minutes (okay more than a few minutes) of sanding done right. 

So let's break down exactly how to properly sand epoxy resin - what grit to start with, what mistakes to avoid, what tools actually matter, and how to get that flawless surface you're dreaming of. 

Why Sanding Epoxy Matters More Than You Think

Before we start grinding, it's important to understand why sanding is such a big deal. 

Epoxy doesn't magically lay down perfectly flat every time. Dust happens. Temperature fluctuations happen. Life happens. Sometimes your pour cures with little bumps, low areas, or texture. And while frustrating is totally normal. 

Sand is what: 

• Can level an uneven surface
• Remove imperfections
• Promotes adhesion for a final flood coat
• Creates the base for a glass-like polish
• Makes every detail of your art or woodworking stand out

Think of sanding like the primer before your makeup, the stretch before your workout, the "is my oven empty?" check before preheating. It's the prep work that makes everything else better. 

When You Should Sand Your Epoxy Resin

This is one of the biggest questions we get, and understandably so - touching resin before it's ready is a good way to ruin a project, and your feelings. 

Here's the rule of thumb:

Sand ONLY when the epoxy has fully cured. 

Not dry to the touch. Not "seems fine." Not "I poked it with my finger and noting stuck". Fully cured! 

Cure times vary by formula: 

• Promise Table Top Epoxy: ~24-72 hours
• Promise Deep Pour Epoxy: ~48-72+ hours
• Promise 1 Hr Fast Cure: ~1 hour (but wait a full 24 hours before sanding)

If it still feels soft, rubbery, or tacky, do not sand. Unless you're intentionally trying to make a gummy mess that clogs your sandpaper instantly. (In which case...bold move.)

 What You Need Before Sanding

You don't need a ton of fancy tools, but you do need the right ones. Here's the setup we recommend:

Tools & Equipment

• Orbital sander (your best friend)
• High-quality sanding discs (we'll talk grits in a minute)
• Respirator
• Vacuum or shop vac
• Microfiber cloth
• Optional but awesome: sanding block, polishing compound, buffing wheel or pads

Environment

Epoxy dust is plastic dust. It floats. It sticks. It will haunt your shop if you let it. Make sure you're sanding in:

• A well-ventilated space
• With proper PPE
• And ideally not next to your fresh pours

Step by Step: How to Sand Epoxy Resin

Here we go - the full Promise-approved sanding process. 

1. Inspect the Surface

Before you start sanding like a caffeinated wizard, look closely at your epoxy. Check for:

• Texture
• High points
• Low spots
• Dust specs
• Drips or edges

If you can see it or feel it, sanding can fix it. 

2. Choose the Right Starting Grit

People mess this up more than anything else. Starting to high is a guaranteed recipe for wasted time. Here's exactly where you should start based on the surface:

• If it's pretty smooth - start at 220 grit
• If it has small defects - start at 150-180 grit
• If there's real texture or bumps - start at 120 grit
• If it's uneven, wavy, or covered in drips - start at 80 grit
• If it's truly rough - 60 grit is fair game (you're not sanding, you're landscaping)

Remember: epoxy is softer than wood, so lower grits cut fast. Don't be scared of them. Be intentional. 

3. Sand in Slow, Overlapping Passes

This is where technique matters. Keep you sander:

• Flat
• Moving (never stay still)
• Slow and even
• WIth 30-50% overlapping passes
• On a medium speed

Don't press down hard. Let the sander work for you. Excess pressure = heat, and heat = smeared resin, swirl marks, and reget. 

Let the tool do the job. You just guide it. 

4. Move Through Your Grits Properly

This is the magic of sanding epoxy: the sequence. A perfect sanding progression looks like this:

80 -> 120 -> 150 -> 180 -> 220 -> 320 -> 400 -> 600

You don't need to go higher than 600 if you're doing a flood coat afterward. If you are polishing instead of pouring another layer, you can continue up through 800-1500 grit. 

The rule: Never jump more than one grit step. 

If you skip too far ahead, you'll trap deeper scratches under finer ones. They'll show up later, guaranteed.

5. Clean Between Every Single Grit

This is where the pros separate from the "why does it still look scratched?" crew. After every grit level:

• Vacuum the surface
• Wipe with a microfiber
• Inspect in good lighting

Dust from lower grits will create new scratches if you don't remove it. Cleaning between steps keeps your finish consistent. 

6. Fix Any Low Spots or Sand-Through Areas

Even experienced makers occasionally hit: 

• Color layers
• Embedded items
• Wood grain
• Air pockets

It's fixable. All of it. If you find low spots flood them with a thin layer of epoxy. Let it cure. Sand again. For sand through areas pour a full new flood coat - not a patch. Patching creates uneven gloss. A full coat self-levels everything beautifully. 

7. Prep for Your Final Step: Polish or Pour

Once your surface is uniformly matte and smooth, you're ready for the finishing choice. 

OPTION A: Final Flood Coat

This is the go-to for 95% of makers. A flood coat gives you:

• A fully self-leveling gloss
• Glass-clear clarity
• Zero sanding streaks
• A durable gorgeous finish

Before pouring:

• Make sure the entire surface is sanded to 180-220 grit minimum
• Clean extremely well (vacuum + microfiber)
• Pour in a warm room (70-80F is ideal)
• Measure and mix properly - always by volume. 

OPTION B: Polishing Only (No Flood Coat)

If you want the epoxy itself to shine without a new layer you can continue sanding through: 

• 400 grit
• 600 grit
• 800 grit
• 1000 grit
• 1500 grit

Then use a quality polishing compound, buffing pad, and cleaner. This gives you a glossy, glass like finish without an additional resin layer. 

Common Sanding Mistakes to Avoid

• Starting too fine. 220 grit can't fix real texture. 
• Pressing too hard. Creates swirls, burns, and uneven sanding. 
• Using a dirty workspace. Dust from other projects = debris in your epoxy. 
• Not cleaning between grits. Hidden scratches come back. 
• Sanding before the resin is fully cured. It gums up instantly. 
• Staying in one spot too long. Creates low areas or dents in the surface. 

How to Know When You've Sanded Enough

You're done sanding when:

• The surface is completely matte
• There are zero shiny spots
• It feels uniformly smooth
• No bumps remain
• No visible scratches stand out
  

The matte look is exactly what your flood coat wants to grip onto.

Final Thoughts: Sanding Isn't Glamorous - But It's Your Superpower

Sanding is sometimes the most annoying part of the creation process. But here's the truth - perfect epoxy starts with perfect prep. And great sanding is what separates good work from great work.  The more you sand, the better your pours become. The more you understand grits, the more control you gain. The more patient you are, the more flawless the final piece.