Tutorials – Casting Resin Gems

A Beginner’s Tutorial by NyuNyu and Fuu

If you need clear, custom made gems for your costume, resin casting is great solution. These are great for jewelry, magical orbs, CLAMP costumes and more. It’s not nearly as difficult as it may first seem. NyuNyu and Fuu will break down the process for you in this tutorial.


-Clear casting resin & hardener
-Mold release
-2 disposable plastic cups (not paper or wax lined)
-Disposable mixing tool (here a cheap paintbrush…barbecue skewers are another favorite)
-molds (here paint trays)
-resin dye (optional)
-acetone (optional – cleanup)


We used and fully recommend Cast ‘N Craft”s EasyCast as it is a one-to-one ratio which makes mixing a breeze! Please read the directions and safety warnings on whatever product you use. Yes, you should wear gloves, as the chemicals are dangerous, and this stuff is sticky. You will see that I am not in these photos, but that’s because I am a magical girl and nothing can hurt me. You, however, should wear gloves as per instructions.


1. Fill with water
First, it’s a good idea to find out how much resin you”ll need to mix up. Once you mix it up, it will harden within hours and you won”t be able to use it later, so you don’t want to mix up random amounts. Fill up your molds with water.


2. Measure
Now, carefully poor the water from all your molds into a cup. Mark a little above this line with a marker. This is how far you”ll fill the cup with resin. Dump out the cup. (Ooh! Strawberry nails!)


3. Mold release
Spray your molds with mold release. Mold release will help you to remove the gem when your mold is not flexible. Rub it in with your finger to make sure it doesn’t pool in one spot. Allow it time to dry. At this point, also double check that your molds are completely flat and parallel to gravity so that your gems have flat, even backs.


4. Fill
Pour your resin into the cup. As I mentioned before, EasyCast is a one-to-one ratio. Even still, you are better off measuring as the package recommends than just pouring as we sometimes do. If you don’t use enough hardener, your gems could be forever gooey! So make sure you get this part right.


5. Mix
Stir well for about 2 minutes (or whatever your package directions say or whatever you personally feel like). Don’t forget to scrape the sides and your stir stick.


6. New cup
Pour your mixture into a second cup. This is to get rid of possible unmixed resin on the sides of the cup.


7. Add dye
If your gems are to be a pretty color, add this now! These gems are for Princess Sakura from Tsubasa, and are to be a translucent pink. So, about 4 drops of red dye did the trick. Add the dye slowly, starting with just one drop, and adding more until you get the desired color. You can always add more dye, but you can’t remove it, so be careful. The mixture color is representative of the color of your finished gems. It may look lighter on a gem that is much smaller than your mixture. Again, stir your mixture until the color is evenly distributed.


8. Pour
Slowly and carefully pour your resin mixture into the molds. The slower your pour, the less bubbles form, and you don’t want bubbles! Be careful not to top it off to much, because you want nice flat backs on your gems.


9. Check for bubbles
Look over your gems carefully for bubbles or any other problems. Tapping the mold or surface your mold is on can help pop the bubbles. Fuu’s trick is to use a vibrating foot massager. It really works! You may not be able to get every tiny stubborn bubble out, but the less bubbles, the better. Some will come out as the mixture sits. You definitely don’t want any on the gems surface, because those can end up as weird holes on the front of your gem! (Yes, this happened to us…see below.)


10. Wait
Now, it’s a waiting game. We like to allow 2 days for the gems to fully harden. Larger casts will actually cure quicker, believe it or not,  so those may be ready sooner. The temperature affects it as well.  Well, they remain slightly flexible even then, but you don’t want to pop it out too soon. Patience! If you have an adorable whiny dog thing like this, go play with it. Or better yet, go do some sewing on that costume you’re attaching these gems to.


11. Remove
Once your gems are hardened, you can remove them from the molds and have some fun with them before you attach them to your costume, like so. You should be able to pop them out by wiggling your mold around.


Failed resin gems make great…headlights! This miscast was too too warm and had huge bubbles on the surface of the gems.

Addendum: Backing your gems

Additional Materials:
-2 Part Epoxy (the one that cures in 5 minutes)
-Metallic/Mylar paper (found in the scrapbooking section of craft stores)

I know most people use foil, but I find that it crinkles and looks bad. So I recommend getting a heavy paper instead.


Mix up some 2 part epoxy as per package directions.


Cover the back of the gem with epoxy and place it on the metallic paper. Press hard to get all air bubbles out, and hold it while it cures. Yes, hold it until it’s cured. I’ve tried laying books on it for a weight, but sometimes air bubbles still form. So, just hold it. Go watch a K-pop video on Youtube while you wait. It should only take 5 minutes if you bought the right kind of epoxy.


Using small scissors or a craft knife, cut the edge of the paper to be flush with the edge of the gem.


Voila! The metallic backing helps the gem catch the light better.

Now you can attach the gems to your costume. You can directly adhere it with glue (use the glue meant for gluing gems on fabric, or use epoxy if it’s going on a prop/armor). You can also make it removable with a pin back or velcro.

Temperature Tip!
Clear cast resin is low odor compared to other types. Still, pick a well ventilated area that you won’t be spending all your time in. We did the casting inside because it was 90 in the shade and the heat can affect your cast in bad way! I use bathrooms or laundry rooms. Your cast can also go bad if it is too cold. (Not that I would know, living in Phoenix.) Be sure to check the recommended temperature range on the instructions.

Where to Buy?
Hobby Lobby
Jerry’s Art-a-Rama
TAP Plastics
Various online stores

I made a mess!
Be careful when handling mixed resin! The chemicals are similar to a very sticky permanent glue! Quickly clean up any spills or residue on your hands with acetone. That’s why I also mentioned gloves and a dropcloth at the beginning. I WARNED YOU!

Questions? Comments? E-mail nyunyuaz@gmail.com.