How to Sand Epoxy Resin (Without Ruining Your Project)

Can You Sand Epoxy Resin?

If you work with epoxy resin, at some point you'll likely need to sand a cured resin surface. It may be necessary for a few reasons:

1. You’re adding a second or multiple coats of fresh resin.
2. You’re removing surface imperfections like dust, dimples, or bubbles.
3. You need to correct sharp or uneven edges.
4. You prefer a matte finish instead of a glossy one.
   
   

I get it - sanding your cured piece can feel super intimidating. The most important thing to remember is that it will look completely ruined at first, but I promise, it won’t stay that way.

In this post, I’ll walk you through everything you need to know about sanding resin: from safety gear and sandpaper choices to best practices and troubleshooting common issues.

Let's get started!

Video: Watch How to Sand Epoxy Resin

What PPE do you need for sanding resin?

Protective Gear Checklist:

• N95 dust mask: to prevent inhaling fine resin dust.

• Safety Glasses: to protect your eyes.

• Gloves: to keep resin dust off your skin. Heavy-duty nitrile gloves from restaurant supply stores work great.

What grit sandpaper do I need to sand epoxy resin? 

It really depends on what you’re sanding and why.  For most purposes, a coarse sandpaper, anywhere between 80-120, will work perfectly well. But if you're working near bare or thin spots where the artwork may be exposed, you may want to use a finer grit to avoid damage.

If you’re sanding for a matte finish, you’ll need wet/dry sandpaper in progressively finer grits. (We'll get into more detail on matte finishes a little further down.)

Can you sand epoxy resin by hand?

Absolutely! I normally sand small resin projects by hand, however an electric sander is a better choice if:

• You're working on a big piece of art

• You’ve got a thick coat and multiple layers of resin to get through

• You’re resining over something like wood and you want to remove all the cured resin

If you're using a sander the most important thing is to let the sander do the work:  Hold it level, don’t lean on it, don’t hold it on an angle and don’t press down it because this will create uneven pressure.  Uneven pressure is what causes deep swirl marks, grooves, or other issues you'll need to fix later. 

It’s also important not to sand too long in one spot.  Friction creates hot spots which can soften the resin.

What tools do I need to sand epoxy resin?

You'll need a few simple tools for sanding and clean up:

• Sandpaper (or an electric sander): plus sandpaper between 80-120 grit

• A damp cloth or paper towel: for wiping things down

• A paintbrush: for getting into textured areas

• A needle tool, a soft toothbrush or a can of compressed air: these help to remove sanding dust from cracks in wood or the open spaces left from bubbles 

How do I restore the gloss after sanding epoxy resin?

To restore the gloss after sanding, the most reliable way is to apply a very thin coat of resin. If you're working on a small area, a foam brush can help you smoothly apply a very small amount. In some cases, you can also use polyurethane or car polishing compound and a soft cloth to restore the gloss.

1: Adding a Second (or Third!) Coat of Resin Over a Cured Surface

Let’s start with layering - in other words, you want to add another coat of resin to your work. 

The golden rule is that if your resin is cured, you have to sand. It doesn’t matter if the resin cured yesterday or a year ago.  Once cured, sanding is non-negotiable before adding a fresh resin over top.

Why? It's because you need to rough up the surface and create some texture (or "tooth") for the new layer of resin to grab onto. The fresh resin layer is going to grab onto that texture and create a really tight bond with the cured layer.  

It’s really important to note that if you don’t sand your cured resin, you run the risk of the fresh resin layer delaminating or separating from the cured resin layer down the road.

💡 TIP:  If sanding feels like a pain and you know you want to pour multiple coats, there is a workaround. You can pour your fresh layer when the first coat has  been curing for about 3-5 hours. At this point, the resin has thickened but is still tacky enough that the two layers will bond together and cure as one.  This is especially helpful when working with molds, where sanding can be nearly impossible.

In this case, our piece is fully cured, so we’re going to sand.  I’ve got 80 grit sandpaper here, but honestly, just use what you have on hand. I personally wouldn’t go coarser than 80 or finer than 180,  but any sandpaper in between those ranges will do.  You could even use a coarse Scotch-Brite pad.  

You're not trying to remove any resin here - you just want to scuff the surface to create that tooth for the fresh resin to grab onto. That's it. 

💡 TIP: Remember to wear gloves and a mask while you sand.

Once you’ve scuffed up the surface, including the sides, you’ll need to clean up that sanding dust:

• Vacuum or gently wipe away the dust with a damp (not wet) paper towel. Repeat to pick up any remaining fine particles

• Let the surface dry completely — resin + water do not mix well

• Once dry, I like to go over it again with a soft cloth or paintbrush, just to be sure all the sanding residue has been removed

Ok so this is the part where you might be questioning your choices. :)
The surface looks a mess, it looks destroyed, but we're going to pour on a fresh coat, and it’s magical to watch it come back to life. 

I hope that seeing the before and after sets your mind at ease.  Now that our resin is poured, it looks bright and beautiful again!

Cover it as usual, let it cure, and you’ll never know it was sanded.

Now what if you’re adding artwork to the cured resin surface before you pour a fresh layer?  
You may be painting a design with acrylic paint, applying gold leaf, or adding collage elements. 

In this case, you don’t need to sand those areas - the art materials will provide that texture for the new resin layer to grip onto. But you do need to carefully sand the bare cured resin around your design before you pour your fresh coat.

If you’re working on a piece of wood with holes or cracks, use a dry paintbrush or a can of compressed air to get all the dust out of those little crevices. 

If you’ve sanded to get rid of bubbles, same thing - a soft toothbrush or a pointed tool can help remove fine dust where the bubble was. It's important to remove the sanding dust so you don't end up with little white dots in your cured piece.

2. Fixing Mistakes

Now let's move onto what is probably the most common reason for sanding - and that's to fix an imperfection in the resin. 

• This could be dust, a stray hair, or an insect that landed in the wet resin while it was curing. 

• It might be surface dimples from resin curing in cold or fluctuating temperatures. 

• It could be bubbles on the resin surface or just below. 

• It could even be a scratch that occurs long after the resin has cured.


Whatever the reason, the only real fix is to sand the problem out and repour.

Now remember how in the last section we only wanted to scuff the surface between layers?  This time we actually want to remove resin - the resin with the imperfection - so we’re going with a coarse grit sandpaper.  I’m using 80 grit here because it can move a lot of resin in a short time.

How much do you need to sand?

It really depends on what you're dealing with. 

• If you’ve got surface bubbles or dimples all over, you’ll want to sand the entire piece down evenly.

• If you’ve just got one area, like a fly or piece of dust, sand that spot out and give the rest of the piece a scuff.

• If it’s something deeper, like a fly or a trapped bubble, you’ll need to sand down until you’ve removed it completely. Just go slowly, and stop to check your progress often. A lightly damp cloth can help wipe away the cloudiness so you can see where you’re at.

A great thing about resin is that it self-levels, so you don’t have to worry if you've sanded more deeply in one spot. Once you pour the resin on, it’ll go where it needs to go, filling in the lowest areas first and then it will even itself out across the surface.

In areas where there’s risk of damaging the artwork, such as bare spots or thin layers of resin, it can help to switch to a finer grit sandpaper to give you a little more control.  Take your time. Sand carefully and slowly. All should be good.

Can you fix just one spot without have to sand the entire surface?

We get this question often:  If there's just one little flaw, do I really need to sand and repour the entire piece?  Can't I just sand and re-resin that one area?

It's a fair question. The answer, unfortunately, is probably not the one you want to hear. 

We don’t recommend spot fixing for the simple reason that it’s difficult to get a seamless finish. You'll almost always see the outline where you patched.

Instead, sanding and recoating the entire piece gives you one smooth, even pour. 


See the side by side comparison below - one side is patch fixed and the other side is fully sanded and re-coated.  The results speak for themselves!

Of course, it’s totally up to you and it depends on your piece too:  if the artwork is busy or textured, the patch may not be noticeable. And honestly, the worse-case scenario is that you try to spot fix first.  If you don't love the results, you can always sand and re-coat the whole thing.

3. How To Sand Sharp or Uneven Edges

Sharp or uneven edges can happen, especially when you’re pouring resin into molds. As the resin cures and levels out, it can rise up the sides of the mold and create a thin raised lip which can feel quite sharp.

To smooth these, some artists like using a deburring tool which carves off the edges.

💡 TIP: Be very careful - deburring tools should only be used around the 24 hour mark, on resin that hasn’t fully cured yet and is still flexible. These tools are very sharp and you can really cut yourself if you try to carve hardened resin. 

If you're not careful, deburring tools can also create a rough, choppy edge.

Personally, I prefer going around the edges with an emery board or a nail file instead. It's gentler and gives you a bit more control. 

You can also place your piece down flat on a sheet of sandpaper and gently rotate it in a circular motion to get a nice, even finish.

💡 TIP: Try not to move the piece back and forth in the same position without rotating it or you will likely end up with an uneven edge. 

Instead of sanding the edges, another option is to pour a small amount of resin to fill in that shallow dip.  This will give it a pretty, domed, glassy look.  It's a beautiful finish, but just keep in mind it might not be ideal for coasters and other items that are better off flat.

Another common issue with molds? The mold may not have been sitting totally level as the resin was curing. When you pop your piece out, it may not sit flat.

Luckily, this is an easy fix - just run it along sandpaper (remember - in a circular motion) until everything is level.

How to restore the gloss after sanding resin edges

Once you’ve sanded, how do you get the shine back?

Here are a few easy options to restore the gloss to sanded resin:

• Apply a very very thin layer of resin with a foam brush.  Use less than you think to avoid creating drips. 

• Use a water-based polyurethane for a glossy finish without adding another resin layer.

• Try polishing compound or car polish and a soft cloth to bring your piece back to a beautiful shine.

4. Sanding For A Matte Finish

Finally - maybe you're not after a high-gloss shine on your resin. A soft, buttery matte finish can look absolutely beautiful - and it's easier to achieve than you might think!

Check out our side-by-side comparison below:

To get a matte finish, you'll need a fully cured piece of artwork, some wet/dry sandpaper in progressively finer grits (I used 320, 600, and 1500), a spray bottle of water, and a soft cloth. 

You can also finish it off with a bit of wax to get just the right amount of sheen, from a velvety matte to a subtle, soft shine.

Start by wetting the surface and sanding it down with 320 grit. You'll notice a paste forming as the sanding residue mixes with the water. 

Move on to 600 grit, then 1500, always sanding with water and wiping clean beteween each pass. Make sure you're happy with the surface before moving on to the next grit.  If you still see scratch marks, you may need to jump back to the previous grit and sand some more.

When you've finished sanding, give your piece a good spray down with water and wipe, repeating until all traces of the sanding residue have been removed.  Dry your piece off well. 

Then apply a thin coat of wax using a soft cloth, rubbing it in small circles to buff it out. You can use a polisher if you like, but keep in mind that the more you polish, the shinier it will get.

Stop polishing when there’s no more haze and you're happy with the finish - whether that's a super soft matte or something with a bit of a glow. 

💡 TIP:  For the full process, check out our blog How To Get A Matte Resin Finish

Quick Recap: Key Tips for Sanding Resin

• Always wear a dust mask when sanding resin

• Cured resin should be sanded. Cured resin is slick, so sanding creates the texture or "tooth" for the fresh resin layer to grab onto. Paint or other art materials on the surface can also help new resin stick. 

• Use a coarse sandpaper like 80 grit to remove surface imperfections. If you're simply scuffing the surface between layers, use what you have, ideally between 80-120 grit.

• Sand deep enough to remove flaw and imperfections, but take care around things like bubble holes or cracks in wood. Clean out sanding dust from these areas before you pour a fresh coat.

• Avoid sanding so deep that you damage artwork.  Sand delicately with a finer grit around areas of exposed artwork. 

• Spot fixing is tricky and doesn't result in a seamless finish.  You’re better off sanding down and repouring the entire surface.

• Restore the gloss by applying a thin coat of resin, clear polyurethane or car polish.

• For a matte finish, use wet sandpaper and work your way up through different grit levels until the surface is smooth. Finish it off with wax and polish it with a soft cloth to the exact shine you want. 

Sanding resin can look messy and feel stressful, but it’s a normal part of the process. Whether you’re layering, fixing flaws, or going for a matte finish, just follow the steps, and your piece will look polished and professional in the end.

We hope you enjoyed our tips - if you have any questions, comments, or tips of your own, please leave them below!




Check out some of our other troubleshooting guides:

Tips To Keep Dust Out Of Your Resin Art

Amine Blush - What It Is and How To Prevent It

Why Are There Bare Spots In My Cured Resin?

Why Is My Resin Cloudy?  The 6 Main Causes

Should I Seal My Artwork Before I Resin?

How To Clean Up Epoxy Resin

How Does Cold Weather Affect Resin?

How Does Hot Weather Affect Resin?

Tips To Prevent Resin Bubbles

How To Fix Sticky Resin

Why Does My Resin Look Yellow?

ArtResin:  The Original Epoxy For Resin Art.