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How to Sand Epoxy Resin (Wet & Dry Sanding)

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Sanding epoxy resin is usually advised to achieve a smooth surface. However, the process isn’t as easy as it sounds, and there are certain things that you must be aware of while sanding epoxy resin. Therefore, we have come forward with a detailed step-by-step guide on how to sand epoxy resin easily. 

Also, we’ll highlight some of the pro tips to make this difficult task seem like child’s play and safe.

Methods of Sanding Epoxy Resin

Before getting into the process of sanding epoxy resin, you must know which sanding method you should use. So, we’ll discuss two ways of sanding epoxy resin and help you understand which one is for you. 

Wet Sanding Epoxy Resin

Wet sanding involves spraying water on the surface to be sanded and using waterproof sandpaper to sand afterwards. The purpose of using water is to eliminate friction so that you can easily sand the surface, exerting less force. Also, it helps to keep sandpaper cool.

Although orbital sanders can also be used for wet sanding, we don’t recommend it. It is due to the possibility that water could get into the sander’s motor and cause damage or any other electric hazard. 

When to use wet sanding for epoxy resin: We’d recommend wet sanding epoxy resin if you’re working on small and sensitive things (Jewellery or decoration pieces) where orbital sander can cause damage. Also, if you wet-sand more oversized items, you will have to put in a lot of effort (because of the larger space area). If you can make an effort and are ready to spend some time, you can also wet sand more oversized items. 

Dry Sanding Epoxy Resin

As the name suggests, dry-sanding epoxy resin doesn’t involve water and waterproof sandpaper. 

In dry sanding epoxy resin, you start with coarse grit sandpaper attached to an orbital sander and work through progressively finer grits to achieve the desired level of smoothness. (We’ll discuss the sandpaper grits details later in the process)

When to use dry sanding for epoxy resin: It’s best to go with dry sanding if you’re dealing with a large piece (such as a table or any furniture), as it will be difficult to rub sanding paper on a large surface with your hands. But that’s not the rule, and you can still use wet sanding to sand epoxy resin. 

Now that you know which method best suits you, let’s get to our step-by-step guide.

How to Wet-Sand Epoxy Resin?

So, let’s start with wet-sanding epoxy resin. By the end of this article, you’ll be able to sand epoxy resin easily and safely. Follow our step-by-step guide: 

1. Gather All Necessary Tools 

The first step is to know which tools you should have on board for wet-sanding epoxy resin. Below is the list of tools that you should gather: 

Waterproof sandpaper – Waterproof sandpaper comes in grit sizes from 60 to 1000 grit (60, 120, 180, 240, 800 to 1500 grit). Starting with a higher grit, like 120-grit for epoxy resin, is always advised. This is because waterproof sandpaper of less than 120-grit can cause scratches and dents on the epoxy, which will be very difficult to conceal afterwards.

Sanding Pad – Another alternative to waterproof sandpaper is a sanding pad.

Safety – When using sandpaper with your hand, you must protect your hand with a pair of safety gloves. Though wet-sanding doesn’t produce a lot of dust, you should still protect your lungs with a face mask. 

Water – Gather some water in a container, as you have to pour at your object. We generally use spray bottles to shower water sprinkles. 

A piece of cloth or a brush – To clean your object in the beginning and at the end of sanding. 

2. Clean the Surface 

Now that you have all the tools for your wet sanding epoxy mission, the next step is to clean the surface you’re going to sand with a piece of cloth you gathered in step 1. 

Here, you need to understand that we’re not washing away the first from the surface with the water. We’re just using water to make the area wet. So, cleaning is necessary to get rid of any dust particles that may cause problems while sanding.

3. Pour water on the epoxy

Get the spray bottle you used in step 1 for water or any other water container. Pour water on the surface of the epoxy to make it wet.

How to pour water on epoxy resin: You can use foam to soak water from the container and squeeze it a little on the surface. If you’re using a spray bottle, sprinkle water over the surface. Please avoid pouring too much water.

4. Sand the Epoxy Resin

Rub the sandpaper on the wet surface of the object (epoxy resin). Another alternative to waterproof sandpaper is a sanding pad. Also, make sure not to exert so much force; hold firmly and repeat this process a few times at a moderate speed.

You should start sanding with the 120-grit sandpaper (which you have gathered in step 1) and repeat the sanding process with a finer grit. For final finishing (before polishing), use 1500-grit sandpaper. 

Start: 120-grit sandpaper 

Middle: 320-400 grit sandpaper

After the middle of sanding: More than 800-grit sandpaper

Final finishing: 1500-grit

It totally depends on the finishing requirements and object. However, if your epoxy resin is really harsh, you can start with 60-grit or 80-grit sandpaper. 

Make sure to keep track of the area you have sanded already to avoid uneven sanding.

Related Read — How to Wet Sand Plastic

7. Cleaning & Polishing

After you’re done with wet sanding your epoxy resin, clean the surface again (just like you did in step 2). If, after going through each step we’ve mentioned, you can still not achieve a smooth finish and still can see some scratches (caused by the sandpaper), you should polish your surface. 

For this purpose, it’s best to use a polishing rouge to make the scratches finer. You should use a polishing compound with the polishing rouge for finer results. 

Related Read — How To Wet Sand a Clear Coat?


How to Dry-Sand Epoxy Resin?

Learning how to dry-sand epoxy resin is hard, there are a lot of steps included. To make things easier, we have made a 6 step guide that will teach you all you need to know about dry-sanding epoxy resin.

The process of dry sanding epoxy resin is not too much different from wet sanding. But there are a few things that work differently in this process. Without further ado, let’s get to the guide: 

1. Tools for Dry Sanding

Sandpaper – You don’t need waterproof sandpaper since you wouldn’t be using water. For dry-sanding, you should get coarse, medium, -grit, and fine-grit sandpaper (120, 180, 240, 320, 400, 800 to 1500 grit). Also, ensure you get quality sandpaper because dry-sanding renders sandpaper dull quickly. In dry sanding, sandpaper gets dull quickly, so make sure to gather some extra sandpaper before starting your dry sanding project. 

A sander – For dry-sanding, this is non-negotiable. Sanding epoxy resin is usually tricky, and it’s not a task I’ll advise you to take on by hand. Since you are not using water, you can get an electric sander or just use a battery-powered one.

We’ve enlisted some of the best orbital sanders after testing each one. So, if you want to get one, check our detailed review: Best Random Orbital Sanders

Safety – Dry-sanding will produce a lot of dust and, possibly, chemical particles. You will need a high-quality grade face mask to protect your lungs, goggles to protect your eyes, and gloves to protect your hands. Do not take any chances with this.

A cloth or a soft brush – To remove the dust particles from the epoxy. 

2. Prepare & Power your Orbital Sander

The next step is to attach sandpaper with the orbital sander. We’d recommend using 120-150 grit sandpaper at the beginning. 

How to attach sandpaper to the sander? Clean the sanding plate, remove the paper from the adhesive side of the sandpaper, and stick it to the sanding pad. Press the sandpaper to make sure it sticks evenly.

After attaching the sandpaper, attach the suction pipe (If your sander comes with a vacuum), and turn on the sander. Practice on a tinier piece first if you’re a beginner. We’ve done many sanding projects, but we still practice somewhere else before sanding our actual objects.

Related Read — Best Combination Sanders

3. Sand the Epoxy Resin

After attaching the 150-grit sandpaper and powering the sander, you can go ahead to sand. Make sure to avoid pressing the electric sander too hard (as it would stop the Sander’s vibrating motions)

Depending on the type of epoxy resin you are working on and the finish you are aiming for, you might still need finer sandpaper. For best results, you should use this sequence:

120-grit sandpaper 5 passes (Horizontal & Vertical)
180-grit sandpaper 5 passes (Horizontal & Vertical)
240-grit sandpaper 5 passes (Horizontal & Vertical)
320-grit sandpaper 5 passes (Horizontal & Vertical)
400-grit sandpaper 5 passes (Horizontal & Vertical)

Clean your surface to check the results; if you still notice scratches, keep sanding with 800-grit sandpaper with 7-8 passes. In the final finish, you should use 1200-1500-grit sandpaper (still, if some scratches are left, they will go away with polishing). 

The sequence that we’ve mentioned is not the general rule. We told you because this works for us every time. Again, it depends on your object and finishing requirements. 

Do clean the surface you’re sanding several times between the sanding process to check the sanding progress. 

6. Clean & Polishing the surface

In dry sanding, you’ll end up with many dust particles on the surface of the epoxy resin (even with a vacuum, you may get some particles on the surface). Clean the surface with a cloth or a brush to eliminate all the dust particles, and see if your sanding has given you desired results. 

If there are still a lot of scratches, you should keep going with sanding with finer grits. If there are minor scratches, you can eliminate those using a polishing compound and polishing rouge.

That’s how to dry-sand epoxy resin. Simple right? We’re sure it is.

Related Read — How to Sand a Door With an Electric Sander


Tips to Follow While Sanding Epoxy Resin

Ensure the Epoxy Resin Is Fully Cured (Dry) Before Sanding

Sanding wet or epoxy resin that hasn’t fully cured can be very dangerous to your health. This is because epoxy resins are made from different chemicals. If you sand the epoxy resin before it fully cures, the chemical particles will be released into the air, and you can inhale them.

Do Not Use Lower-grit Sandpaper if You Have Moved to a Higher-grit

For instance, if you have sanded with 150-grit sandpaper and are now using a 240-grit, do not return to the 150-grit.

Using lower-grit sandpaper will only result in a very uneven and poor finish. So ensure you are done with grit before you move to a higher grit.

Keep your sandpaper and Sander Disc Clean

While dry sanding, you have to deal with dust particles on the surface and in the surroundings. That’s why you get a rough finish after using your sander correctly. 

We’d suggest you stop sanding if you feel that dust has accumulated in the sander disc. Remove the sanding paper, and clean it properly. Also, clean the sander disc with an air compressor or blower.

So there you have it. Please comment below if you have questions or comments about how to sand epoxy resin. Have a great sanding experience.

Related Read — How to Sand A Deck?

 Tips to Follow While Sanding Epoxy Resin

Ensure the Epoxy Resin Is Fully Cured (Dry) Before Sanding

Sanding wet epoxy resin or epoxy resin that hasn’t fully cured can be very dangerous to your health. This is because epoxy resins are made from different chemicals and if you sand the epoxy resin before it fully cures, the chemical particles will be released into the air and you can inhale them.

Do Not Press on the Sander

If you are dry-sanding, do not press on the sander. Most people press on the sander so it doesn’t vibrate. This will only ruin your finish.

You are to hold the sander firmly while sanding not press it down on the surface. You should also pause regularly while sanding to inspect the surface so you don’t over-sand.

Related Read — Best Straight Sanders

Do Not Use Lower-grit Sandpaper if You Have Moved to a Higher-grit

For instance, if you have sanded with 150-grit sandpaper and you are now using a 240-grit, do not go back to the 150-grit.

Using lower-grit sandpaper will only result in a very uneven and poor finish. So ensure you are done with grit before you move to a higher grit.

So there you have it. If you have any questions or comments about how to sand epoxy resin, please leave a comment down below. Have a great sanding experience.

Related Read — Belt vs Orbital Sanders

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We’re a team of engineers, contractors, technicians, and woodworking experts who use power tools daily and share fact-based information, tips, and recommendations. At thetoolgeeks.com, we debunk myths about power tools and share methods to use them effectively.

The Tool Geeks Team

We're a team of engineers, contractors, technicians, and woodworking experts who use power tools daily and share fact-based information, tips, and recommendations. At thetoolgeeks.com, we debunk myths about power tools and share methods to use them effectively.

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