Sanding Epoxy Resin [Complete Guide on How to Sand Epoxy Resin]

Sanding epoxy resin is one of the most tedious tasks in boat repair. Epoxy resin has a high viscosity and requires special tools to sand it effectively. The process can also be quite messy, requiring large quantities of water or solvent for cleanup after you are done with your project.

This blog post will cover how to use the right type of abrasive paper to get an even finish on your epoxy, what types of dust masks are best for this job, and some other tips on how to make your task more manageable while still producing good results. We hope that this information helps you out!

Table of Contents

  • What Is Wet Sanding Epoxy Resin?
  • Should You Wet Sand or Dry Sand Epoxy Resin?
  • Difference between Wet Sanding and Dry Sanding Epoxy Resin
  • When Should You Dry Sand Epoxy Resin Instead of Wet sand?
  • How to Wet Sand Epoxy Resin? (7 Easy Steps)
  • How to Dry Sand Epoxy Resin? [7 Easy Steps]
  • 5 Epoxy Sanding Tips
  • What Grit to Use When Sanding Epoxy Resin?

What Is Wet Sanding Epoxy Resin?

Wet sanding and polishing epoxy resin with waterproof sandpaper is the best way to repair sand epoxy. Wet sand prevents blush of amine when sanding, removes sandpaper clamping, and partially cures dust and exposure to epoxy. It allows the sandpaper to go deeper and shows that everything is appropriately sanded.

Water improves the efficiency of cutting through flushing surface material from the abrasive surface to the substratum. In addition, the water maintains the abrasive surface clear of debris and hence does not obstruct the abrasive surface.


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Should You Wet Sand or Dry Sand Epoxy Resin?

In sanding epoxy resin, you should wet sand instead of dry sand. Although both methods function correctly following all the instructions, the results of dry sanding cannot be contrasted with wet sanding.

Besides the effect, the entire sanding process with wet sanding epoxy resin is much easier than dry sanding. In the process, dust is minimized by applying water to the surface until it is sanded.

Dry sanding creates a lot of dust, and you should not forget that epoxy resins are also made from various chemical substances. Organic particles can also be accelerated in the atmosphere as sand is dry, and if you inhale, both of these substances can damage the respiratory system. You should use respirator mask.

Difference between Wet Sanding and Dry Sanding Epoxy Resin

You just need to get your hands on the required sandpaper and sand. Wet sanding includes pouring water on the surface and sanding with waterproof sandpaper. As you guessed, dry sanding needs no water or waterproof sandpaper.

Related: Wet Sanding vs Dry Sanding: Know the Pros and Cons

When Should You Dry Sand Epoxy Resin Instead of Wet sand?

Exceptions can exist where dry sanding gives better results. Wet-sanding wood epoxy resin, especially light wood, is generally not recommended because wood usually absorbs moisture quickly and can affect its condition.

Dry sanding would be your best option when dealing with epoxy resin mixed or sanding epoxy resin on wood. It is also suitable for other humidity-sensitive materials. As a suggestion, you can make sure that you put good breathing protection if you are going to dry-sand epoxy or something.

How to Wet Sand Epoxy Resin? (7 Easy Steps)

Step-1: Arrange tools and materials for wet sanding epoxy

You must arrange these powerful wet-sand epoxy resin instruments. Waterproof grain sandpaper is inexpensive. For better results, you should begin with higher grain, like 120-grit. That is because less than 120-grit waterproof sandpaper scratches on the surface.

For wet sand, sanding pads are useful. It needs a pair of gloves, protection against breathing, wooden wraps or pieces to cover paper, water, clean rags, and a soft bowl.

More Info: Waterproof Sandpaper – What is it?

Wet sanding of epoxy resin generally requires waterproof sandpaper. It has a closed layer of silicon carbide. The paper is available in between 60 and 1000 grits. However, since too little grain can cause deep surface scratching, one should begin with a grain of 120 or more for the epoxy resin part.

Only considerable patience and difficulty can remedy the scratch-related damage. You can wet-sand your art to 3000 grains if you want to get a good shine on the resin surface. The surface of the epoxy resin can be cleaned with a polishing material and a polishing machine.

Related: How to Use Wet Sandpaper – Know 7 Easy Steps

Step-2: Clean the Surface

Put your protective equipment in. Your safety equipment includes your pair of gloves, breathing aid, a couple of goggles if needed, and everything that will protect you against sanding harm and injury.

You need to ensure that the surface is free of any debris until you sand. Leaving the waste on the surface before the sand can also lead to cuts and contusions while you are sanding by hand. To clean the floor, use a clean rag or a soft brush.

Step-3: Get Water Ready for Sanding

Before and during sanding, you must add water to the surface. You can either have a water bowl or bucket readily available or place a spray bottle of water.

Only choose the correct method for you. Do not use hot water on epoxy because the heat will melt the epoxy and become very messy. To use wet sand epoxy resin, use cold or warm water.

Step-4: Wrap the Sandpaper around a Block if Needed

Wet sanding typically takes place by hand but can be difficult for most people since epoxy resin is usually tricky. You should wrap the sandpaper in a way that is suitable for you.

Also, remember the size of the surface to be sanded so that you can wrap the sandpaper in a way that makes sanding easier. If you find many curves on the surface to be sanded, you can go on a sanding pad.

Step-5: Sand the Epoxy Resin

You should start sanding epoxy resin after cure the surface and the sandpaper. Epoxy resin usually isn’t rough, so violent or coarse sandpaper shouldn’t be necessary.

You can start with the 60-grit or 80-grit sandpaper if you note that the epoxy resin has several irregularities. You must exercise extreme caution if you use coarse sandpaper because the wrong stroke or motion will ruin epoxy.

Related: Sandpaper Grit Chart for Different Projects

Step-6: Spray Water on the Epoxy Resin Surface

To sand, spray water from your spray bottle on the floor. If you don’t have a spray bottle, you can dump a bowl of water on the surface or just dip it into a bucket of water and sand.

After you apply water, rub the abrasive side of the sandpaper in a circular motion against the surface of the epoxy resin. You should repeat it a few times.


You should note where you sanded and where you haven’t, primarily when you work on a large surface. This prevents you from sanding over. You should finish the surface with sandpaper after sanding with coarse sandpaper or medium-grit sandpaper.

Step-7: Clean the Surface

After some sanding, clean the surface and inspect the surface with a clean rag. This will be much simpler when you wet-sand the surface.

When you sand, you can clean the surface with a damp rag again and then dry it. Any remaining debris or sand is often recommended to be removed from the surface, as it is harder to do so as the epoxy resin dries.

Do you want to know how to polish epoxy resin after sanding the epoxy resin?

For doing this, you can apply a small amount of clean polishing cloth onto the resin surface and rub it vigorously. Let it sit for a second, and buff it off with another piece of tissue. Then apply a polishing compound to the surface.

If the resin of epoxy is dry, you have completed the job. That’s how epoxy resin is wet-sand. Now, let’s see the dry-sanding.

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How to Dry Sand Epoxy Resin? [7 Easy Steps]

Step-1: Arrange tools and materials for dry sanding epoxy

Before starting epoxy sanding resin, you should collect all the required equipment. You need sandpaper, an electric sander or battery-operated sander, breathing protection, a couple of gloves, a pair of glasses, and a rag for dry epoxy sand.

A random orbital sander is the best option for removing epoxy resin. With its high-speed and dustless qualities, this tool can work with little or no mess on any surface (even polyester). By using different orbits during your cycle as needed you will get perfect results every time!

Step-2: Prepare the Surface

You should take the same preparatory steps as for wet sanding until you go into the sand. This involves washing the sanding surface and placing your safety gear. Remember the dry-sanding causes a lot of pollution to protect yourself.

Step-3: Provide a Well Ventilated Space

You should get a well-ventilated work area before you dry-sand the epoxy resin. If possible, transfer the epoxy resin surface outdoors.

This gives you more floor space to work with. You just don’t have to be too concerned about inhaling the radioactive dust. If the Epoxy Resin surface can’t be moved outdoors, ensure that all doors and windows are fully open before you start to sand.

Step-4: Attach the Right Sandpaper

You need to apply the correct sandpaper to the bottom of the sander since you use a sander. You can start with coarse sandpaper on the surface for a very rough resin like the 80-grit sandpaper. You need 120-grit of sandpaper or 150-grit of sandpaper to begin sanding epoxy resin surfaces.

The instructions for attachment of the sandpaper are typically provided on the sandpaper and the sander. Most of the Sanders use a sandpaper clamp. The pin can be released by pulling a lever-which is usually placed behind and along with the sander.

Step-5: Power the Sander

You can control the sander and switch it on after adding the right sandpaper. If the sanders are an electric model, the cord should be plugged in. If this model is battery-powered, you can slot it into the battery.

Step-6: Sand the Epoxy Resin

You can go to sand after adding the right sandpaper and pulling the sander. Put the sander’s bottom on the sanding surface and pull the lever.

You should begin slowly so that you can keep track of your work. Sanders vibrates a lot when being used, and keep your sander tightly so that your job will not be ruined. Do not put too much weight on the sander or over-sand the field.

Dry sanding can make the sandpaper dull quickly, so you should have an alternative. If you find that the sandpaper is no longer fine, replace the new one with the sandpaper. Finish with 240-grit sandpaper or 320grit sandpaper to the sanded area.

Step-7: Clean the Surface

Since dry sanding can spread a lot of dust, a clean rag or soft brush should be used to clean up the sandy surface and remove residue in epoxy resin after sanding. You can then continue to finish the surface. It’s like dry-sand resin epoxy.

5 Epoxy Sanding Tips

  1. 1

    Sand Resin and Wood Separately
    You should isolate sand epoxy from wood. Epoxy resin is a material that is entirely different from wood and calls for a different sanding technique and grain series. This extends to projects for wood and resin, such as epoxy fluvial tables and resin wall art. This tip helps avoid the incorporation of fine resin dust into the wood fiber.

  2. 2

    Keep Sandpaper Clean
    Sanding induces heat, which makes the sandpaper build up with the fine resin dust. Until the sandpaper is removed, this resin is built between the sandpaper and the epoxy surface. As a result, the surface is sanded by swirling pigtails and burn-in.

  3. 3

    Use Proper Sanding Tools
    When sanding and buffing epoxy resin, you should use quality tools matter. In particular, the right instruments facilitate the operation, achieve great results, and promote protection.

  4. 4

    Use Quality Sander
    You should use the Festool RO125 because this sander regulates dual-mode, variable-speed dust. You can also use Rotex mode to orbit epoxy resin randomly. It is possible to use random orbit vibrations that yield incoherent effects.

  5. 5

    Use Correct Sandpaper
    The sandpaper you choose is very important. Festool Granat NET sandpaper can be used mainly when sanding epoxy resin. This sandpaper makes it easier to collect and lasts for a long time.

What Grit to Use When Sanding Epoxy Resin?

The sequence and direction of the sanding grain are critical when sanding the epoxy resin.

You can start sanding with 120-grit sandpaper.

Then you can switch to and from 150, 180, 220, 320 grit-sandpaper.

For flat-finish, use 220 to 320 grit. For satin finish, use 400 to 600 grit. For semi-gloss, use 800 to 1000 grit, and for gloss, use up to 1200 grit.

Final Words

Epoxy resin sanding is effective in wider areas that are moisture-free. Wet sanding is usually performed by hand. Do not use an electric sanding machine for epoxy resin while doing wet sanding; otherwise, you could experience an electric shock. You can also use an air sander for large surfaces.

I hope by reading this guide, you would able to execute the epoxy-resin process accurately.

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