Sanding Epoxy Resin: How to Polish an Epoxy Finish

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Epoxy resin is popular for creating durable and glossy finishes on various surfaces, including woodworking projects, countertops, and artwork. However, achieving a smooth and flawless surface requires sanding the cured epoxy resin. 

Through this guide, I’m excited to share with you the methods and techniques I’ve honed for sanding epoxy resin — the very same ones that have served me and my fellow woodworking professionals well. We’ll dive into the best tools to use and I’ll pass along some tips that will help you achieve those professional-quality results we all strive for.

Best Method & Types of Sanding Epoxy Resin + Best Tools

Sanding epoxy resin requires specific tools and techniques to ensure the best outcome. Here are some of the best methods and tools for sanding epoxy resin:

Method 1: Dry Sanding

Dry sanding is a common method used for sanding epoxy resin surfaces. It involves using sandpaper or sanding discs without water or any liquid lubricant. Dry sanding is suitable for small-scale projects or areas that require targeted sanding.

dry sanding epoxy resin

Pros of Dry Sanding

Cons of Dry Sanding

Method 2: Wet Sanding

I’ve often turned to wet sanding when I’m aiming for that ultra-smooth, polished look on my epoxy resin projects. It’s a technique where I use water or sometimes another liquid lubricant to cut down on friction and help clear away any residue while I sand. It’s one of those tricks that can make a huge difference in the finishing touches.

using orbital sander on epoxy resin

Step-by-Step Wet Sanding Process

1. Wear a Dust Mask

Before starting the wet sanding, wear a dust mask to protect yourself from inhaling fine particles or sanding dust.

2. Prep Your Sandpaper

Soak the sandpaper or sanding pads in water for a few minutes to soften them and allow better lubrication during sanding.

3. Wet the Resin

Wet the surface of the epoxy resin with water or lubricating fluid to create a smooth gliding motion while sanding.

wet sanding epoxy resin

4. Switch Directions While Sanding

Sand the epoxy resin surface in a back-and-forth or circular motion, frequently changing directions to ensure even sanding and prevent visible scratches.

5. Proceed to the Next Higher Sandpaper Grit

Start with lower-grit sandpaper and gradually progress to higher grits for a finer finish. Rinse the surface with water periodically to remove any sanding residue.

6. Recoat with Resin

After completing the wet sanding process, clean the surface thoroughly, and consider applying a fresh coat of epoxy resin to restore the glossy finish.

Pros of Wet Sanding

sanding epoxy resin after spraying with liquid

Cons of Wet Sanding

What's Amine Redness? Why Should You Remove It?

Amine redness, or amine blush, is common when curing epoxy resin. After curing, it appears as a hazy or cloudy film on the resin surface. 

While it is not harmful or structurally damaging, removing amine redness is crucial for achieving a clear and glossy finish. Sanding is an effective method for eliminating amine blush and restoring the resin’s clarity.

Method 3: Waterproofing Sandpaper

When wet sanding epoxy resin, I’ve learned that waterproofing the sandpaper really pays off. It enhances the sandpaper’s durability and extends its lifespan, which is something I can’t recommend enough if you’re looking to get the most out of your materials.

various types of sandpaper

It can be done using a waterproofing solution or simply immersing the sandpaper in water before use. Waterproofed sandpaper lasts longer and provides smoother sanding results.

Method 4: Using Sanding Pad or Block

Sanding pads or blocks are versatile tools for sanding epoxy resin surfaces. They come in various shapes and sizes, providing comfort and control during sanding. 

Sanding pads or blocks can be used with dry and wet sanding techniques, allowing for consistent and even sanding.

Method 5: Using Dremel Tool

A Dremel tool with sanding attachments or rotary sanding drums is useful for sanding intricate or hard-to-reach areas on epoxy resin surfaces. 

Dremel 4300-5 40 High-Performance Rotary Tool Kit

A Dremel tool’s small size and high-speed rotation enable precise sanding and detailing, making it ideal for delicate projects or fine-tuning specific areas.

Method 6: Using Air-Powered Sander or Electric Sanding Machine

An air-powered sander or electric sanding machine can benefit larger epoxy resin surfaces or extensive sanding projects. 

These tools offer increased efficiency and speed in sanding larger areas while maintaining control and minimizing fatigue. They often come with variable speed settings and dust collection systems, providing a more convenient sanding experience.

How to Sand Epoxy Resin Areas Properly

I can’t stress enough the importance of proper technique and the right tools when it comes to sanding epoxy resin. Over the years, I’ve picked up a handful of essential tips that really make a difference in sanding epoxy resin the right way. Here’s what’s worked for me:

1. Sand Resin and Wood Separately

If you’re working on a project involving epoxy resin and wood, we recommend sanding them separately. It helps prevent cross-contamination of sanding residue and ensures a cleaner and more precise sanding process.

coffee table with epoxy resin finish

2. Keep Your Resin Sandpaper Clean

Frequently clean the sandpaper or sanding discs during the sanding process to prevent clogging. It can be done using a sandpaper cleaning stick or simply tapping the sandpaper against a hard surface to dislodge any accumulated debris.

3. Utilize Proper Sanding Tools

Choosing the right sanding tools is essential for achieving desired results. Here are a few recommended tools for sanding epoxy resin:

Random Orbital Sander

A random orbital sander is a versatile tool that combines both rotary and orbital motions, providing smooth and swirl-free sanding results. It is suitable for larger epoxy resin surfaces and offers efficient material removal. 

(But how does an orbital sander compare to a belt sander? Find out next!)

Resin Sandpaper

When sanding epoxy resin, it is crucial to use sandpaper specifically designed for resin applications. Resin sandpaper features a stearate coating that resists clogging and extends the lifespan of the sandpaper.

waterproof sandpaper

Dust Collection

To minimize dust and maintain a clean working environment, consider using a sanding tool with a built-in dust collection system or attach a dust collection attachment. It helps reduce airborne particles and makes the sanding process more efficient. Here’s a review of the best small shop dust collection that you can use. 

The Grit of Sandpaper Sequence & Direction

When I’m working towards a smooth and flawless finish on my epoxy resin projects, I’ve found that the secret is in the sequence of sandpaper grits I use. Let me walk you through a general guide for the grit sequence that I follow:

1. Start with a coarser grit

Begin with lower grit sandpaper, such as 80 or 120, to remove any imperfections or unevenness on the epoxy resin surface.

2. Progress to finer grits

Gradually progress to higher grit sandpapers, such as 220, 320, 400, and beyond, for a smoother and finer finish. Each successive grit helps remove the scratches left by the previous grit, resulting in a progressively smoother surface.

220 sandpaper grit

3. Sanding Direction

When sanding epoxy resin, it is recommended to switch sanding directions frequently. It helps prevent visible scratches and ensures an even sanding result. 

For example, switch to a circular or diagonal movement in the next sanding pass if you start sanding in a back-and-forth motion. This technique helps blend the scratches and achieve a more uniform surface.

Epoxy Resin Sanding Direction

When sanding epoxy resin, sanding against the grain or pattern of the resin is generally recommended. It helps to minimize visible sanding marks and achieve a smoother finish. 

However, it is essential to consider the specific characteristics of your epoxy resin and adjust the sanding direction accordingly.

Control the Sheen of Epoxy with Sandpaper Grit

Sandpaper grit plays a crucial role in controlling the sheen or glossiness of the epoxy resin surface. Finer grits, such as 400 or higher, are ideal for achieving a high-gloss finish. A coarser grit, such as 220 or 320, can be used if a satin or matte finish is desired.

sandpaper

How to Sand Resin Smooth

To achieve a smooth surface on epoxy resin, consider the following techniques:

1. Using a Sanding Belt or Power Sander

A sanding belt or power sander can expedite the sanding process for larger epoxy resin surfaces, such as tabletops or countertops. Use a fine-grit sanding belt or sanding discs suitable for epoxy resin and sand in a controlled manner. 

Be cautious not to apply excessive pressure or linger in one area for too long, as it can generate heat and potentially damage the resin.

2. Sand Resin Tables & Other Big Objects

When sanding large epoxy resin objects like tables, it is advisable to use an orbital sander. Orbital sanders operate in a circular or elliptical motion, reducing the risk of leaving visible sanding marks. 

Use sanding discs with appropriate grits for resin applications. Begin with a coarser grit to remove imperfections and progress to finer grits for a smoother finish.

3. Orbital Sanding Epoxy Resin

Orbital sanding is effective for achieving a smooth finish on epoxy resin surfaces. Use an orbital sander with sanding discs or pads suitable for epoxy resin. 

dry sanding epoxy resin

Start with a lower grit to remove imperfections and gradually work up to higher grits for a finer finish. Maintain a consistent sanding motion and apply even pressure for optimal results.

4. Sand Resin Jewelry & Other Tiny Objects

Hand sanding is often the best approach for small epoxy resin objects like jewelry. Use resin-specific sandpaper or sanding pads and sand with a gentle touch. 

Take care not to damage delicate resin details or edges. Switch to finer grits as needed to achieve a smooth surface.

5. Artwork & Other Small Objects

Artwork and small epoxy resin objects require careful sanding to preserve intricate details. Consider using sanding sticks or foam sanding pads for better control and precision. These tools allow targeted sanding in small areas without affecting the surrounding resin.

Problems When You Sand Epoxy Resin

Sanding epoxy resin may pose a few challenges, including:

sanding resin project

1. Heat Buildup

Excessive heat generated during sanding can affect the clarity and finish of epoxy resin. To prevent heat buildup, avoid extreme pressure and take breaks during the sanding process to allow the resin to cool down.

2. Visible Scratches

Using the wrong grit or sanding direction can result in visible scratches on the resin surface. Be mindful of the grit sequence and frequently change sanding rules to achieve a uniform, scratch-free finish.

3. Dust and Airborne Particles

Sanding epoxy resin creates fine dust particles that can be harmful if inhaled. Always wear a dust mask or respirator and work in a well-ventilated area to minimize exposure to airborne particles [1]

Additionally, consider using a dust collection system or attaching a vacuum to the sanding tool to capture dust and maintain a clean working environment.

How to Avoid Sanding Resin to Get a Smooth Surface

I’ve been around the block a few times with epoxy resin, and while sanding is my go-to for getting that smooth finish, I’m always exploring alternative approaches. There’s more than one way to skin a cat, as they say, and the same goes for finessing epoxy resin surfaces. Here are some other methods I consider:

resin project

Recoat with a New Resin Coat

If the epoxy resin surface has minor imperfections or scratches, applying a new coat of resin can help to fill in the gaps and create a smoother finish. Follow the manufacturer’s instructions for using a fresh resin coat, ensuring proper surface preparation and curing time.

Spray Finish the Are

A spray-on finishing product designed for epoxy resin surfaces can achieve a smooth and glossy finish without sanding. These products create a protective layer that fills imperfections and enhances the resin’s shine.

Fill it with a Doming Resin.

Using a doming resin can help fill in gaps and create a smooth, rounded appearance for small imperfections or uneven surfaces. The domed epoxy resin creates a thick, self-leveling layer that can even out minor irregularities.

Is it Okay to Sand Sticky Resin?

Sanding sticky or uncured epoxy resin is not recommended. It can gum up the sandpaper, leading to poor sanding results and potentially damaging the resin surface. 

sticky resin

Allow the epoxy resin to fully cure according to the manufacturer’s instructions before sanding it. Fully cured resin is harder and easier to sand effectively.

FAQ

Is sanding epoxy harmful?

Sanding epoxy resin can produce fine dust particles that can be harmful if inhaled. Taking proper safety precautions when sanding, such as wearing a dust mask or respirator and working in a well-ventilated area. 

Use dust collection systems or attach a vacuum to the sanding tool to minimize airborne particles.

How long to wait before sanding epoxy?

The curing time for epoxy resin can vary depending on the product and environmental conditions. Follow the manufacturer’s instructions. 

The epoxy resin must cure for 24 to 72 hours before being ready for sanding. Ensure that the resin is fully cured and hardened before proceeding with sanding.

Conclusion

Sanding epoxy resin is crucial in achieving a smooth and flawless finish on various projects. By employing the appropriate sanding methods, utilizing the recommended tools, and following the proper techniques, woodworkers, DIY enthusiasts, and artists can transform epoxy resin surfaces into stunning works of art. 

Remember to prioritize safety by wearing appropriate protective gear, maintaining proper ventilation, and following the manufacturer’s instructions for the epoxy resin and sanding products. 

robert headshot

Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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