How To Make Resin Coasters Two Ways

Image of a resin coaster with the caption “How to make resin coasters.”by Kate Ledum

If you are looking for an easy and fun way to make a handmade gift, then this resin coaster project is for you!

Making small resin charms from other projects, then including them in a new project like this resin coaster DIY, is a great way to double the handmade fun. This project will show you how fun it is to learn how to make resin coasters with resin leaves and shells you’ve already made.

If you’re asking yourself how to make resin coasters without making your own resin charms, don’t worry. You can make these coasters with found objects or just about anything!

Two completed resin coasters with leaves and seashells.

 

In the tutorial Using Pearl Ex with Resin Two Ways, we made a variety of resin leaves and shells using the same techniques. These are perfect for including in a resin coaster.

Colorful resin leaves on a doily.

 

Other small castings such as bugs, beads, flowers, or buttons will work great, too. The items will also need to be smaller than the coaster mold. The mold we’ll be using is 4” in diameter and 3/8” deep.

Supplies for your how to make resin coasters project:

For this resin coaster DIY mold project, I’m using the Resin Obsession super clear resin. It cures hard and durable, making it a great choice when learning how to make resin coasters.

 

 

I am also making the two resin coasters slightly different from each other.

 

Two round silicone molds.

Deciding Which Way the Resin Coaster Should Face

The first thing you do for a project like this is to decide which side you want to be at the top of the coaster. If you want the side facing the table to be the top, you will need to put everything in upside down. Otherwise, if you want the side facing you to be the top, everything will be facing up. It can be much easier to arrange them the way you want if you have everything facing you since you can see exactly how it will look. With everything facing the table, you can lift the mold and look at it from underneath, but that can be risky while you have liquid uncured resin in it.

The coaster mold has a very gently sloped side, making the mold’s diameter slightly smaller on the tableside. If you make the coaster with the table side up, the top of the coaster will be slightly smaller than the bottom. If you make the coaster with the side facing you as the top, the top will be slightly larger than the bottom. Either way will work well as a coaster.

For this specific tutorial on how to make resin coasters, the leaves coaster will face toward you, and the shell coaster will face the table. For steps that are the same for both coasters, only the leaves project is shown.

Placing resin leaves into a silicone mold.

 

Decide What to Put In the Resin Coaster

Place the charms you want to use into the mold. See how they’ll fit and how you like them placed together.

Covering the resin mold with a piece of paper to test for flatness.

 

PRO TIP: Since a coaster needs to be flat to do its job, you must make sure all the items you put in the mold do not rise above the edge. One way to check this is to place a piece of paper across the top of the mold. As long as nothing is touching the top of the paper or poking it up, everything should fit once you add the resin.

Resin leaves in a dry mold.

 

PRO TIP: You can take a picture of how you placed your items in the dry mold to use as a guide when putting them in with the resin later.

Spraying a silicone mold with mold release.

 

Prepare the Coaster Mold

Spray the mold with the mold release and set it aside to dry for at least 30 minutes.

 

 

Prepare the Resin and Your Work Area

Before you start mixing the resin, you should put on a pair of protective gloves.

Resin likes a warm (but not hot) room. For best results, 72 to 74F is the recommended temperature for how to make resin coasters.

A plastic bag in a salsa pot.

 

Warming resin in water will help reduce bubbles in the mix. You can use a bowl with hot (not boiling) water or an electric salsa pot for no more than 5-10 minutes.

Two silicone molds with cups of resin and stir sticks.

 

 

Measure and Mix the Resin

I’m mixing a bit more than 3 ounces of resin for both coaster molds. The marks on my resin mixing cups are essential to making sure I get accurate measurements.

  1. In one cup, pour in enough of Part A to reach the 50 ml mark.
  2. Pour 50 ml of Part B into a second cup.

 

 

Combining resin in a graduated mixing cup.

 

  1. Combine Part A and Part B.
  2. Using a stir stick, scrape the sides of the cup while slowly stirring the resin to mix the parts. This helps to reduce the number of bubbles in your mix.
  3. Scrape the side of the cup with a stir stick several times while combining the two parts.
  4. Mix until everything goes clear, which takes about two to three minutes.
  5. Then, pour the mix into a third cup and mix for one more minute to ensure all the resin is thoroughly mixed.

Pouring clear resin into a silicone mold.

 

Pouring the First Layer of Resin

Pour a small amount of resin into the mold.

Tilting clear resin around to coat the bottom of a silicone mold.

 

 

To evenly coat the bottom of the mold, you can tip it slightly from side to side. You want only about 1/8” to cover the bottom of the mold.

Pouring clear resin into a measuring cup.

 

 

Leaves Resin Coaster

For the leaves resin coaster, we will have the side of the mold facing up to be the finished top of the coaster. This means we’ll be placing the leaves, so they’re facing us as we work.

Pour a small amount of resin into a small cup. Using a small resin cup for the next stage is much more manageable than a large one. In addition, covering items with liquid resin helps avoid trapping bubbles when putting them into the mold.

 

Placing resin leaf into a clear resin cup.

 

Drop one of the resin leaves into the small cup and spoon resin over it with the stir stick.

Holding resin coated leaf with a stir stick.

 

Once it’s coated with liquid resin, pick the leaf up with your stir stick and slip it into the mold into the thin layer of resin.

 

Positioning resin leaf into a mold.

 

Adding leaves to a silicone coaster mold.

 

Add more resin leaves, first covering each in resin. Then, use your stir stick to move them around in the mold as desired.

Silicone coaster mold filled with colorful resin leaves.

 

Continue adding leaves. If you took a picture earlier when you were dry fitting them in the mold, you can use it now to arrange them similarly. Push down the leaves to make as flat a surface as possible. Make sure you do not have any leaves poking up higher than the sides of the mold.

PRO TIP: While placing leaves, you can carefully pick up your mold and, without tipping it, you can look at it from the bottom through the clear plastic to see if you trapped any big bubbles. If you did, now is the best time to deal with them.

Pouring resin over leaves in a mold.

 

Pouring Additional Resin

After you have arranged the leaves, pour in enough resin to cover them but not so much that it overfills the mold. Pour the resin to about 1/8” below the lip of the mold. Use your stir stick to push down any of the leaves that are too high.

Resin seashells in a coaster mold.

 

Shell Resin Coaster

We are going back over to the shell mold. For this mold, we will have the side facing the table as the finished top of the coaster. Repeat the resin mixing steps above in this How To Make Resin Coasters tutorial on adding a thin layer of resin to this mold.

Just as with the leaves, coat each shell with resin before you put it into the mold. Place the shells, so their back is facing you. If you have other resin shells than the ones we cast in the first tutorial, you can add them as well.

Once the shells are placed, pour in additional resin but stop at about 1/4” from the top.

Using a heat tool on a resin coaster.

 

Popping Bubbles

To help reduce bubbles in the resin coaster, you can use a heat tool or lighter for popping surface bubbles. You might have to use a toothpick or the edge of a clean stir stick to scoop out bubbles that won’t pop. When you have inclusions in the resin, it’s essential to check them, too. Bubbles can get trapped in the shapes.

Just as with the leaves, coat each shell with resin before you put it into the mold. Place the shells, so their back is facing you. If you have other resin shells than the ones we cast in the first tutorial, you can also add them.

 

Leave to Cure

Cover your molds with a box or container and wait for the resin to cure. It is always best to cover your curing resin because you don’t want dust, cat hair, or other unwanted things to become part of your project.

Clear resin coaster with shells.

 

Add Sand to the Shell Resin Coaster

After the shell coaster has cured at least 4-5 hours, the resin should be gel phase. You can add more resin at this point or wait until it’s fully cured to add the next layer to the coaster.

TIP: You can do this step after the first layer is fully cured for precisely the same effect. The two layers of resin will create a permanent bond.

Resin coaster with shells curing.

 

Do not remove the coaster from the mold, and be careful not to break the seal at this time. If air is between the cured resin and the mold, the new resin will flow into that space and ruin the project.

Pouring clear resin over a seashell coaster.

 

Mix another batch of resin and pour a thin layer onto the first resin layer. You don’t need to pour much resin; only enough to coat the back in a thin layer.

Pouring clear resin into a stirring cup.

 

You can use natural sand for this layer, but you can also make faux sand by mixing a couple of colours of Pearl Ex and adding in some chunky glitter. Natural sand would work the same way as this artificial sand.

 

 

Mixing sandy resin next to a seashell mold.Pour a tiny bit of the resin into another cup. Add the sand to the second cup and, with a second stir stick, slowly stir to combine the sand with the resin. Try not to introduce bubbles into the mixture. When the sandy resin is ready, it will look a lot like watery mud or a slurry.

 

Pouring sandy resin into a coaster mold.

 

Pour the sandy resin into the mold over the shells.

Poured sandy resin in a silicone mold.

 

Continue filling the mold with sand and resin until it is about 1/8” from the top edge. This helps to avoid overfills. If there are still bits sticking up, don’t worry. There are a couple more steps left.
Just as before, use a heat tool for popping any bubbles and then set the coaster to cure.

Pulling a resin coaster out of a mold.

 

Removing the Resin Coaster from the Mold

After more than 24 hours after the last resin pour, the coaster should be ready to unmold.

Carefully bend the mold while pressing from the center back of the mold. Continue lightly bending the mold until you can lift part of the resin coaster free. Because we used mold release at the start, the coaster should come out without much effort.

Unmolded resin coasters right after release.

 

If you are using a plastic resin mold, you don’t want to twist it so hard that it bends out of shape, just enough to break the seal between the mold and the cured resin. Sometimes a whack on a hard surface, like a desk, can help break the seal, just like when you need to break the seal on a new jar of jam. If the seal still doesn’t want to break, you can put the mold into the freezer for 10-15 minutes. Then, when you take it out, give it a whack on the counter or desk. Once you start to see a bubble of air between the mold and the cured resin, you’ve won.

Cutting the edge of a resin coaster with scissors.

 

Finishing the Resin Casting Edge

When you cast in a mold and don’t fill to the absolute top of the edge or dome, the resin will cure ever so slightly concave. This will leave a sharp and potentially uneven edge all around that’s difficult to show in pictures, but your fingers will feel it.

You can carefully cut away the majority of the sharp edge with a sharp pair of scissors. The resin is pretty thin in this location and can be simply cut away. Make sure you cut around the mold evenly.

Sanding the edges of a resin coaster.

 

You can also sand the resin edge. A nail sander from the dollar store works great because it’s an easy shape to hold in your hand, and the sanding surface is not too coarse. You generally don’t want anything rougher than 400 grit.

Be sure to wear safety glasses any time you are sanding resin. It’s also best to wear a paper breathing mask to avoid inhaling any of the resin dust.

Testing a resin coaster for flatness with a cup.

After taking off the edge, you should do a ‘tip test’ to see how flat the coaster is to determine what other steps we might need to do.

Put a water bottle or cup on the resin and tip the item from side to side. If it doesn’t rock, then the coaster is flat enough. If it does rock, you’ll need to do something to make it flatter. Either add a thin coating of more resin or sand off the bits that stick out. This is an important nuance when learning how to make resin coasters.

Holding a resin coaster at an angle to see protruding shell shapes.

 

On the shell coaster, a couple of the shells extend further than the ‘sand’ layer. This can be detected in the tip test and also just by looking from the side. Since the bottoms of the shells are sticking out the back, let’s sand them down a bit.

Sanding down a coaster with seashells.

 

When sanding a large area of resin, not only can it create a large amount of resin dust, but the friction can heat the resin and cause some melting. Sand the coaster in a pool of water to accommodate this. A cheap foil pan works well.

WARNING: If any item is used with uncured or resin dust, it is unsafe to use it with food after.

To sand evenly, move it over the sandpaper in a figure-eight motion. Check the edge to make sure it’s smooth to the touch as well.

Only sand to flatten on the backside of your coaster. However, if you need to flatten the top and want to preserve the inclusions that might be protruding a little, you can add a small layer of doming resin to the top.

Cutting a coaster base out of cork.

 

Adding a Cork Base to the Resin Coaster

Since the shell coaster in this How to Make Resin Coasters tutorial has an opaque bottom, this is a perfect time to add a cork bottom. It will also be less likely to scratch any surfaces. You could also use felt for this step.

Trace the mold onto the cork with a pen or pencil. Then, cut it out on the inside of the line.

A disc of cork covered in glue.

 

Slather the cork disc with craft glue. Be sure to get the glue out to the edges and not too thick.

 

 

Hand pressing cork onto a resin coaster.

 

Place the cork disc to the back side of the coaster and press firmly to adhere well.

Adhering bumper pads to resin leaf coaster.

 

Adding Clear Dots to the Coaster Base

After the leaves design of our resin coaster project is fully cured, we can finish it, too.

To preserve the transparent look of the coaster, we’ll add some clear dots to the bottom. This will help prevent the coaster from scuffing surfaces and keep it from moving. You can buy bumper pads at hardware or craft stores. They are usually in the area of hardware for hanging pictures or cabinet doors.

Finished coaster with leaves and clear dots.

 

Most bumper pads are self-adhesive. Simply peel them off and stick them where you want.

Since I wanted a clear look with the leaves coaster, I placed them behind the opaque leaves. You want the pads evenly spaced, so the coaster doesn’t rock when something is placed on it.

 

Two completed resin coasters with leaves and seashells.

 

Finished Resin Coasters

Tada! We now have two coasters from our How To Make Resin Coasters tutorial made with resin items we cast earlier. It was fun making two styles using the same coaster mold. This tutorial also covered a lot of techniques you can apply to endless resin projects.

Ready to take on more projects like this resin coaster DIY? Then you will want to get your copy of Resin Jewelry Making. The Amazon best-selling PDF ebook contains several projects you can make this weekend! Buy now, and a download to read the book arrives in your email in only a couple of minutes.

 

Unpublished Blog Posts of Resin Obsession, LLC © 2021 Resin Obsession, LLC

Like this post? You may be interested in  Resin in bezels - How to make a resin pendant using a bezel blank

44 thoughts on “How To Make Resin Coasters Two Ways

  1. Does resin stick to glass? I have an idea for something similar but I want a free form edge so I’m looking for a surface to pour on. Would putting the mold release on a glass surface be enough?

      1. Looks amazing! I have sunflowers growing and I was thinking of cutting some of the heads and making a few coasters for my grandparents. Is mold release absolutely necessary with silicone molds or does it just make it easier to remove?

  2. I have been making coasters with resin, but am running into the problem that when a mug with hot coffee/water whatever is placed on the coaster it leaves a ring on the coaster that doesn’t come off. What can you do to prevent this or stop this?

      1. Hi there,
        I would also like to know what resin to use to avoid “heat rings” from hot beverages being set on coasters. Please don’t forget about us!
        Please advise!
        Thanks,
        Renée

  3. Regarding the checking for bubbles on the underside – in order to keep the mold stable – could you move the mold (after the pour) onto a piece of plexiglas or glass so that you could easily pick it up and look at the bottom side of the mold?

  4. I’m wanting to make a resin coaster with a river running through it. How can I separate these spaces so the colors don’t blend throughout? Any suggestions would be great, I’ve never done any resin work before.

  5. How do you keep drinks from sticking to the coasters? I’ve got them nice and flat, but drinks are sticking if the glass has any condensation on it.

  6. I am trying to do a small desk top. I covered it with small shells and a few larger ones that I want to stick out a bit . I covered with polyurethane resin but it wasn’t enough . Later I covered with another thicker layer but I could not have been so careful it has not dried. What do I do ? Plus it still needs more. Advice please. I had nobody to advise me from the beginning.

  7. I would like to pour resin into a baked polymer clay ring dish. I would like to submerge a small dried flower from my father’s funeral into the resin. Which type of resin do you suggest?

      1. thank you! I’m so excited to receive my order and get started! I ordered some dolls to take apart, inspired by your monster high bracelet.

        Also, can you direct me to another blog that explains how to keep insertions from tipping?

        1. Yeah! Can’t wait to see your doll bracelet.

          I’m not sure I understand what you mean by ‘insertions from tipping’. Can you tell me more?

          1. Sure! I’m not hip with resin lingo, so my apologies for the confusion!

            I tested a bangle bracelet with small metal gear charms. Instead of staying the in the positions in which they were placed, they leaned forward or backward in the mold. Is there a way to prevent that? I used an epoxy resin.

  8. Whenever I make coasters, even though they appear nice and dry and smooth, the glasses stick to them. Even if they are empty with no hot or cold liquid in them.Apparently, many resiners have the same problem.

  9. Hi Adele! I didn’t. I’ve abandoned bracelets and am perfecting coasters. What I’ve learned, and is probably relevant to the tipping problem, is two things: wall building or waiting. If you want an inclusion to sit a certain way, it has to be supported by a cured wall of resin. I’ve also learned that waiting 30-40 minutes, before inserting, let’s the resin thicken. At that point, you just have to be diligent about keeping things upright until the resin cures to where it’s just about gel. Perhaps YouTube has the answer!

  10. Love this article. So much good informatiin. I love making resin crafts, picture framed glass, coasters, sun catchers. This is the best explanation I have seen, and I have read many before starting! Thank you!

  11. On a dresser tray made from resin (to keep rings perfume bottles on), if perfume drips on it will that ruin the finish?

    1. Hi Marion, I wouldn’t expect it to, but I can’t say for sure. If you wipe it up right away, you should be fine.

  12. I made six resin coasters with molds. Three dries good but the other 3 did not. Still sticky after 3 weeks. Is there anything I can do?

  13. Hello
    Can you pls tell me how to make sure my projects don’t concave?? I’ve tried to fill like suggested but then it ran over. How do you do it??? HELP!!! Thank you

    1. Hi Cindy, unfortunately, there is no easy way to keep this from happening. The more you work with a specific resin, the more you will gain a feeling on how much to overpour so that it shrinks close to flat.

  14. Are they heat resistant? Can I put There A coffe or only A glass od water? Because my resin coasters are not heat resistant

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