4 Best Methods to Sand Resin Easily

One of the many reasons we love crafting resin products is their glassy and smooth finish. However, to achieve that, you’ve to put in a bit of effort by sanding your epoxy resin. After properly sanding epoxy resin, you get a polished and smooth surface that is like a cherry on the top. Another reason why you need sanding is to get rid of sharp edges. This ensures that the finished product doesn’t hurt the users.

If you’re new to resin crafting and have no clue as to what sanding epoxy resin is, continue reading this article to have all the answers.

Difficulties When Sanding Epoxy Resin

Sanding epoxy resin can be quite tricky if you’re new to it. At times, it can get difficult because once the resin cures, it becomes hard, making sanding quite laborious.

Some of the issues that may hinder the sanding of your resin include:

• The powdered resin removed from the resin product gets added to the abrasive paper, thereby making it dull and ineffective, thus requiring it to be cleaned or even replaced frequently.
• Another main concern when sanding epoxy resin is the harmful effects of powdered resin. When inhaled, this powder can get absorbed easily into our respiratory lining because of the small size of its particles. This, in turn, can cause irritation and/or inflammation of the respiratory tract and lungs.

But don’t let these difficulties hold you back! Below we’ve mentioned different ways you can sand your epoxy resin while avoiding these issues.

What is the Best Method of Sanding Epoxy Resin?

When it comes to sanding epoxy resin, there are numerous methods that you can make use of. Here, we’ve provided you with a brief overview of these methods to outline which of these is best and which ones you should try to avoid.

So, let’s get straight into it!

1. Waterproof Sandpaper

Waterproof sandpaper is used for wet sanding of epoxy resin. Waterproof sandpapers come in various grit sizes ranging from 60 to 4000. Using waterproof sandpaper is the best method for sanding epoxy resin for two reasons:

• The sandpaper lasts longer as it doesn’t get clogged during sanding. This is because the added water quickly removes resin dust from the surface of the material.
• Resin dust produced is much lower, providing a much safer environment for working.

2. Sanding Pad / Block

Sanding pads, also known as pad sanders, are powerful handheld tools used for the purpose of sanding resin. These sanding pads have a pad incorporated in them which is attached to the motor. The pad is made of materials like hard rubber and comes in various shapes. The sandpaper is attached to the pad either by applying pressure or clamps. These sanders are used for even sanding. An added benefit is that these sanding pads take the resin dust in during the sanding process.

3. Dremel Tool

Dremel tool makes use of rotatory motion to even out resin surfaces. It can also be used to carry out epoxy resin sanding. But as with all other electric tools for sanding, you have to be careful when sanding with Dremel tools.

Some things to keep in mind when sanding with Dremel are:

• Make sure that the polishing head is fitted on the Dremel
• Do not apply too much pressure as it can deform the resin.
• Work slowly and take breaks at intervals to avoid overheating the resin, which can result in melting the resin.

4. Air-powered Sander / Electric Sanding Machine

Air-powered sanders are tools that make use of compressed air to power rotating sanding discs. Air pressure is controlled by a button present on the sander. Electric sanding machines are powered by electricity to perform sanding. These tools are to be employed when you want to carry out dry sanding of your resin.

They can greatly reduce the time and effort required to sand your resin. For this reason, it is perfect for large pieces.

Wet Sanding of Epoxy Resin

Wet sanding of epoxy is the best method for sanding.

Not sure when to go for wet sanding?

• When working with casting resin that is greatly affected by high temperatures, you should definitely go for wet sanding (dry sanding is a big NO in this case). This is because dry sanding produces a lot of heat which can cause the resin to melt.
• Wet sanding makes use of water as a lubricant which makes it less abrasive. This property of wet sanding greatly adds to the final finish of resin making it smooth and shiny.
• Also, if you’re working with small resin crafts such as jewelry or key chains, you should opt for wet sanding.
• Wet sanding greatly improves the performance of sandpaper because the added water absorbs the resin dust preventing it to add to the sandpaper.
• Even if you’ve done dry sanding in the initial sanding process, it is better to go for wet sanding near the end of the sanding process. This gives the resin a smooth glassy finish.

Now that you have decided that wet sanding is the best option for your epoxy project, let us take you through this procedure one step at a time.

Wear the dust mask

The first thing to do when starting resin dusting is to put on a dust mask. This is to prevent inhaling resin dust, which is hazardous and can cause irritation and inflammation. Even though wet sanding doesn’t produce much dust but better safe than sorry.

Prepare your Sandpaper

For a smooth finish, you have to be aware of the grit of the sandpaper you’re using.

Don’t know what grit is? The grit of sandpaper refers to the abrasiveness of the sandpaper.
The higher the grit number, the finer your abrasive.

For a finer and smooth finish, you should gradually go from lower to higher grit sandpapers. Low grit sandpapers are coarser, while higher ones are finer and are used later for a smooth finish. Start sanding your resin with 150 grit sandpaper and gradually move towards higher ones. It is preferred to start with this grit size because a lower grit size can put deep scratches on the surface.

For wet sanding, you should always go for waterproof sandpapers. To ensure that your sandpaper stays smooth while sanding, you’ve to provide it with suitable backing. You can do so by wrapping it on a rubber sanding block.

Wet your Resin

This is the part where water comes in the process of wet sanding. You have to make your resin wet quite frequently during this process. You can do so by dipping your resin in water or by using a spray bottle. Once you’ve made your resin wet, you can continue your sanding.

Switching Directions While Sanding

Wet sanding is mostly carried out by hand. This can lead to uneven sanding because it may be possible that you’re applying more pressure on one side without being aware of it. To deal with this issue, all you have to do is frequently change the direction of sanding.

Here’s how you do it:

• Let’s assume that you’re sanding from left to right. Once you see the edges turn white, stop sanding and make your resin wet.
• Use a paper towel to dry it partially.
• Now when you start sanding again, you've to make sure that you sand from right to left.

You can also go from south to north and north to south. Sanding in the pattern of digit eight is also advised to ensure even sanding

Move to the Next Higher Grit Sandpaper

Once you notice that you’ve made sufficient progress, you should move to the next higher grit sandpaper. Don’t jump directly from 150 grit sandpaper to 1000 grit sandpaper. To achieve the desired results, move gradually towards higher grit sandpaper.

Recoat with Resin

Once all the sanding marks are gone, now is the time for you to apply a new resin layer. This will give your resin a shiny and glassy finish. You can also use wax for this purpose.

How to Remove Amine Blush

Amine blush is a sticky and waxy layer that forms on top of the resin when it cures in fluctuating temperatures.

This waxy layer is not much visible; however, it can hinder the sanding process and spoil the final look. This layer also prevents the adhesion of the resin to the next coatings and other substances. But worry not. Below are a few ways you can get rid of amine blush:

1. Amine blush is water soluble, so you can use warm soapy water and scrub lightly with a sponge.
2. If soapy water doesn’t work, you can go for spirit and wipe with a cloth
3. Use waterproof sandpaper and lightly rub it on the amine blush to remove it.

Dry Sanding of Epoxy Resin

While dry sanding may not be recommended, there are scenarios where dry sanding is the best choice. Dry sanding of resin is the option when you have to sand larger surfaces. When working with resin that has wood incorporated in it, you cannot go for wet sanding as it can cause the wood to absorb moisture and swell. In such cases, you must use dry sanding.

How to dry sand

• Dry sanding produces a great amount of resin dust. So, make sure you’ve your dust mask on before starting.
• Start from a grit size between 80 to 120 and gradually work your way up towards 1000 or 1200 grit size.
• Dry sanding clogs the sandpaper fast, so clean and/or replace your sandpaper frequently.
• Once sanding is completed, polish your resin for a finer look.

Dry Sanding vs. Wet Sanding

The following points will help you understand why wet sanding is better than dry sanding.

• Dry sanding produces a lot of resin dust which creates an unhealthy work environment. On the other hand, during wet sanding, the dust produced gets mixed with water and doesn’t become airborne. This, however, can be a bit messy.
• Sandpapers last longer in wet sanding and are much more efficient compared to dry sanding. The resin dust in dry sanding causes the sandpaper to clog quickly hence needing replacement or cleaning.
• The heat produced during dry sanding can cause the resin to melt. The application of water during wet sanding keeps the temperature down, thereby preventing the resin from melting.

Tips and Tricks

Sanding epoxy resin can be quite difficult. However, with a few tricks and tips, you’re good to go:

• First things first, put on a dust mask. Sanding produces resin dust which can be quite hazardous when inhaled.
• Make sure that resin is completely dried before sanding.
• Wet sanding can get quite messy. So, if you opt for that, ensure that your workspace is covered properly with a newspaper or tarpaulin.
• Use a paper towel to dry your workpiece frequently during wet sanding.
• Dry sanding can produce heat. So, make sure you take breaks in between to ensure that high temperature doesn’t cause the resin to melt.
• Go from the lowest grit size of sandpaper to the highest grit size gradually.
• Make sure you apply even pressure and change the direction of motion when hand sanding.

Frequently Asked Questions (FAQs)

1. Can you sand epoxy and recoat?

Yes, you can always pour a second coat of resin after sanding if you want to fix any mistakes or create a layered look.

2. How long should you wait before sanding epoxy?

You have to give your epoxy its required curing time before you start sanding. It has to be completely dry to ensure even sanding.

3. What is the best grit sand between epoxy coats?

The preferred grit to use in between epoxy coats is 80 grit because this allows the added coat to settle appropriately and removes any dust.

4. How should you polish epoxy resin after sanding?  

You can use a polishing machine, drill, or a Dremel to polish your epoxy after sanding.

Conclusion

Sanding of epoxy resin creates the perfect finished look for your resin craft. Without this step, you can not achieve the shiny and glassy look typical of resin materials. So, if you want that, you shouldn’t skip resin sanding (no matter how much you dislike doing it). Having read through this article, you must have been aware of what sanding is and how it is done. All that’s left is for you to choose the method which suits you best and start sanding.