How to Set Shells in Resin
In this article, learn how to set shells in resin. Also, I show you how to cast seashells in resin for DIY projects such as coasters and tables.
I included a free resin calculator download at the end of this post, so make sure to get a copy before you go.
Tools & SuppliesEpoxy Resin for Deep Pours
Neutral Aqua Glow Powder
Wood Mixing Sticks
- How to Set Shells in Resin
- Tools & Supplies
- Gather Seashells
- Best Resin for Setting Seashells
- Determine Amount of Resin Needed
- Mix Epoxy Resin
- Pour Epoxy Resin
- Allow Epoxy to Partially Cure
- Setting Shells in Resin
- Resin Thumbprint Test
- Casting Seashells in Resin
- Final Thoughts
- Frequently Asked Questions
For those of you not near a beach, I encourage you to purchase sea shells online or gather them during a beach vacation.
Best Resin for Setting Seashells
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:
- Thinner epoxy penetrates the porous surface and tiny holes better. In turn, better penetration means less bubbles.
- Deep pour epoxy cures slower which helps it form a stronger bond.
Personally, I prefer my epoxy seashell projects with a few bubbles.
They add a realistic underwater feature.
However, too many bubbles and/or large bubbles are not good as it may cause issues over time.
Determine Amount of Resin Needed
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.
Free Resin Calculator
To make this process simple, I included a link to a resin calculator at the bottom of this post.
So, be sure to get a copy before you go.
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.
Mix Epoxy Resin
As a quick tip, use 3 containers when mixing epoxy resin for accurate measurements and proper mixing.
Trust me, it is well worth the money to use 3 containers. In fact, most epoxy resin manufacturers recommend it.
Essentially, I use each container for a different purpose when mixing epoxy resin.
- First Container: Part A
- Second Container: Part B
- 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).
As a quick tip, most epoxy looks cloudy at first.
Eventually, it turns clear when properly mixed and ready.
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.
Pour Epoxy Resin
I poured the epoxy into the area and checked for leaks.
Additionally, I poured resin in cracks to secure the wood.
Next, I removed the bubbles with a mini torch.
Allow Epoxy to Partially Cure
Before setting shells in resin, I allow the epoxy to cure about 30%.
Furthermore, some shells float to the surface if set in place before the epoxy pour.
Or, 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.
Additionally, 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.
Essentially, a small string of resin follows the stick when removed.
Setting Shells in Resin
First, 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
Seal Shells with Resin
To prevent air bubbles, I recommend using 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.
Furthermore, some artists prefer to use fast setting epoxy to seal the shells beforehand.
Again, different strokes for different strokes. 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.
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.
Casting Seashells in Resin
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.
Then, I monitored the epoxy for 30 minutes to remove any air bubbles with my mini torch.
After I learned how to set shells in resin, I began making beach inspired furniture, beach house decor, and resin ocean art using many of the same tips & techniques.
Ultimately, I hope this project inspires you to do the same.
Also, checkout the full seashell epoxy desk tutorial for the complete guide for this desk.
FREE Resin Calculator Download
Complete the form below to download your free resin calculator.
Frequently Asked Questions
How do you harden seashells?
To harden seashells, coat the surface of the seashell with epoxy resin using a foam brush. Epoxy resin will harden seashells and make them more rigid.
How do you cast seashells in resin?
To cast seashells in resin, you must first clean the seashells and seal them with a thin layer of epoxy resin to prevent air bubbles.
Next, secure them to the surface with a thin layer of epoxy resin and allow this to cure.
Then, cast the seashells with deep pour epoxy resin.
How do you set something in resin?
To set something in resin, you must pour a thin layer of resin and set the object in place. Once the epoxy resin cures, the object will be secured in place.
How do you display a seashell collection?
To display a seashell collection, use epoxy resin to cast them in a table top or drink coasters. In addition, a shadow box works well to display a seashell collection.