How to Set Seashells in Resin

In this Instructable, I show you how to set shells in resin along with many resin tips and techniques.

Even if you don’t need to set shells in epoxy resin, the DIY tips I share can be applied to any epoxy resin project such as jewelry, coasters and epoxy tables.

There are several things which are difficult to fully explain with words and images, so be sure to check out the video tutorial.

Seashells

Epoxy Resin for Deep Pours

Mixing Containers

Wood Mixing Sticks

Mini Torch

Nitrile Gloves

Neutral Aqua Glow Powder (Optional)

For those of you not near a beach, I encourage you to purchase shells online or gather them during a beach vacation.

Luckily, my family and I live a few blocks from a beach and gather seashells while snorkeling, paddleboarding, or walking along the beach shore.

If you choose to gather seashells from a beach, please make sure the shell does not have a creature living inside.

Seashells come in many shapes, sizes, and textures.

Most importantly, the shape and porous surface of seashells may trap air and cause bubbles when set in resin.

As a result, I prefer to use deep pour epoxy because:

1. Thinner epoxy penetrates the porous surface and tiny holes better. In turn, better penetration means less bubbles.
2. Deep pour epoxy cures slower which helps it form a stronger bond.

If you already know how much resin you need or don't care too much about using too much or too little, skip to the next step.

In order to set shells in resin, I need to fill the area halfway with resin.

So, I figure out how much resin I need for the entire project and divide this number by 2.

Resin Formula for Gallons & Quarts

The formula I use to determine how much resin I need for a project in gallons:

(L*W*H) * .004329 = # of gallons needed

(L*W*H) * .017316 = # of quarts needed

First, I determine the volume in cubic inches by measuring the length, width, and height of the resin area.

Quick Tip: If the width of the area varies, take a measurement every 6 inches and average the numbers.

Volume = LxWxH

Next, I multiply this number by .004329 to get the number of gallons I need for the entire project.

In addition, I listed the formula to determine the number of quarts as well.

Gallons Needed = Volume * .004329

Quarts Needed = Volume * .017316

Then, divide this number by 2 to get the amount of resin needed to fill the area halfway.

Resin Calculator Example

For example, the area of my project is 47” long, 10” wide, and 1.5” high. So, the volume in cubic inches is 705.

(47*10*1.5) * .004329 = ~3 gallons

(47*10*1.5) * .017316 = ~12 quarts

So, the first pour to set shells in resin needs to be 1.5 gallons (192 ounces).

I used deep pour epoxy for this project which requires a 2:1 mixing ratio.

In turn, I mixed 128 ounces of part A and 64 ounces of part B.

As a quick tip, use 3 containers when mixing epoxy resin for accurate measurements and proper mixing.

In fact, most epoxy resin manufacturers recommend it.

I use each container for a different purpose when mixing epoxy resin.

1. First Container: Part A
2. Second Container: Part B
3. Third Container: Mix Part A and Part B.

My 5-gallon buckets were being used for a different project, so I used 6 small containers (2 groups of 3).

Most epoxy looks cloudy at first. However, it turns clear when properly mixed and ready to use.

Optional Step: Next, I added 4 ounces of glow powder to each 96 ounce container. I use this step in the process to mix any additive to the epoxy such as pigment powder, dye, or glow powder.

I thoroughly mixed the epoxy with a stir stick.

I poured the epoxy into the area and checked for leaks. Next, I removed the bubbles with a mini torch.

Before setting shells in resin, I allow the epoxy to cure about 30%. Some shells float to the surface if set in place before the epoxy pour. Conversely, other shells sink to the bottom if set in uncured epoxy.

By allowing the epoxy to cure 30%, the shells slightly sink and form a bond near the middle of the epoxy.

I prefer to suspend the shells in the middle of the resin rather all the way on the bottom or top.

I check the epoxy every 12 hours by touching it with a stick on one end. Once the resin slightly adheres to the stick, I know it’s time to set seashells. A small string of resin follows the stick when removed.

Resin Thumbprint Test

As a quick tip, I recommend to use the ‘Thumbprint Test’ before pouring additional layers of epoxy.

In other words, the epoxy should be soft enough to leave a thumb print.

If the epoxy sticks to my thumb, I allow it to cure a bit more before embedding seashells in epoxy resin.

However, if the epoxy is too hard for a thumbprint, I know I need to lightly sand the surface before applying a final coat.

I chose the shells from my collection to set in resin. Next, I placed the shells in the resin in a random pattern to resemble a beach or ocean shore.

Once I placed the shells in the resin, they sank a small amount. Then, I allowed the epoxy to cure a bit more before casting the shells in resin

To prevent air bubbles, use a foam brush to apply resin to the exposed shells.I find it easier to do this immediately after setting the shells in resin.

However, it works just as well to seal the shells before setting them in resin. Some artists prefer to use fast setting epoxy to seal the shells beforehand.

Again, different strokes for different folks. I encourage you to do whatever you feel most comfortable with.

Next, allow the resin to cure according to the manufacturer’s instructions and reapply if needed. Keep in mind, I did not seal the shells in this project and had no issues with bubbles.

First, I mixed the second half of resin (192 ounces) and poured the epoxy over the shells very slowly. I find I create air pockets if I pour the epoxy too quickly when embedding seashells.

I monitored the epoxy for 30 minutes to remove any air bubbles with my mini torch.

I hope this instructable provided you with value. Please feel free to leave a comment if you have any questions - I'm happy to help.

Be sure to checkout my YouTube channel and my website for more DIY tutorials.