While crafting my Emerald Carbuncle Attire from Final Fantasy XIV, I’ve been trying my best to learn new techniques and work with new materials. The majority of the costume has turned into something of an “experimentation project,” and honestly, it’s been a blast! I’ve learned a lot already, and I’ve also stumbled upon some fun methods of tackling the more challenging aspects of FFXIV designs. One of those methods is something I’ve taken to calling foam clay casting. It’s exactly what it sounds like: using basic mold-making techniques to cast pieces with foam clay.
FFXIV designs are filled with elements like those pictured below. They’re three-dimensional metal ornaments that are often attached to clothing. As such, they might benefit from some sort of flexibility so that they aren’t damaged with movement.
Specifically, I was tackling the gold ornaments on the back of my Carbuncle jacket:
This method came about during one of my Twitch streams where I was experimenting with C4 Foam Clay. I attempted to sculpt one of the ornaments, but it was a frantic process due to the 25-minute workability limit of the material. The piece was too detailed for me to carve perfectly before the outer “skin” began to dry and crack. Furthermore, replicating that piece with a mirrored partner for the other side of the design in just 25 minutes proved frustrating and unsuccessful.
I lamented aloud that it would be so much easier if the foam clay had a longer working time, more like the plastilina clay I like to use when making masters for casting plastic and resin elements. And then the thought occurred to me: why not carve these intricate shapes out of that clay, use those masters to create molds, and then cast them out of foam clay?
If nothing else, it was worth a shot!
I’m very happy with the end results, so I wanted to share the step-by-step process in case it’s useful to anyone else, especially other FFXIV cosplayers.
Supplies
- C4 Foam Clay (or other foam clay brand of choice)
- Smooth-On Silicone Mold Making Liquid Rubber OOMOO 30
- Plastilina Sulphur-Free Modeling Clay
- Wax Paper
- Plastic Container (such as Tupperware)
- Sculpting Tools
- X-Acto Knife
- Sandpaper (#220)
- Paintbrushes
- Flexbond
- Acrylic Paint + Fabric Paint Medium
- Gorilla Super Glue Brush & Nozzle
Foam Clay Casting Tutorial
Please note: While most foam clays retain some flexibility when dried, they will still crack or break apart if over-stressed. It is important that any primers and paints you use are also flexible. If you would like to cast pieces that are extremely flexible and resistant to damage, I would suggest using urethane rubber or flexible resin. This process came about as an experiment with foam clay specifically, so while it may not be the “best” method for making this sort of piece, it was very beginner-friendly (as well as budget-friendly).
#1. Sculpting: Lay a sheet of wax paper on your work surface and secure it with tape. (If you have a template for your design, I suggest taping it to the underside of the wax paper.) Sculpt your piece using your Plastilina Clay. This sort of clay will not air-dry or harden, so take your time and work carefully!
#2. Smoothing: Once you finish sculpting all your pieces, use a damp sponge to smooth the clay surface. It does not have to be perfectly smooth, as the final foam clay piece will be sandable.
#3. Prepare for Mold-Making: Transfer your clay pieces to your plastic containers; leaving them on the wax paper may assist with this process.
#4. Molding, Molding, Molding: Mix your Smooth-On Silicone Rubber and pour it over your clay pieces. Make sure that it covers them completely, and that the uppermost portions have a significant layer of silicone covering them so that the mold does not tear if the silicone is too thin.
#5. Removing the Master: After 24 hours, your new negative mold is ready to extract from the container! It should come out easily if the container is bent a bit (as if you were twisting an ice cube tray to loosen the cubes). If not, you can use a sculpting tool to gently pry it free. Peel your clay piece from the mold, using your tools to clean out any clay residue that remains.
#6. Foam Clay Casting: Now, break out your foam clay! Press your clay into the negative mold, using firm pressure to ensure that the clay fills every crevice. If the clay “spills over” the edge of the mold, that’s just fine! We’ll be able to cut a crisp, clean edge after it dries.
This “dry time” will vary depending on the brand of foam clay you use. If you’re working with C4, it will take 48 hours for the piece to dry completely. The catch is, however, that we need to expose the inside of the mold to air for it to dry. To achieve this, I carefully peeled my foam clay piece out of the mold after 24 hours had passed; since it was only partially dried, it extracted easily. I let it dry “face up” for the remaining 24 hours.
#7. Clean-Up & Sanding: Use an X-Acto knife to trim off the excess clay from the edges of your piece. Then, take your 220-grit sandpaper and gently smooth away any imperfections in the surface. You can also use your sandpaper to make any micro adjustments to improve symmetry.
#8. Priming: Prime your pieces using Flexbond mixed with a bit of water to improve its ability to smooth over the surface of the clay. I did two layers. Flexbond is a better choice for this purpose than wood glue, as wood glue will not flex with the clay.
(Note: PlastiDip is also an option! Unfortunately, it was a cold week in Michigan when I was making these pieces, so spraying anything outside was a no-go.)
#9. Painting & Finishing: Mix up your acrylic paints to your desired color, then mix in a fabric paint medium. This will allow the acrylic paint to flex without cracking. I needed two coats to evenly cover my pieces.
After the base color was done, I darkened my paint mixture and added some shading to further define the crevices and crannies. This isn’t necessary, but may provide more visual definition on camera!
Once your paint has completely dried, seal it with another layer of watered-down Flexbond.
#10. Attachment: Adhere your pieces to your costume with super glue. I prefer the Gorilla Glue Brush & Nozzle because the brush makes it easy to spread the glue over the surface area of the piece. I attached mine to suede, which provided a “roughened” surface for the glue to adhere. If you’re gluing to a smoother surface like vinyl, use your X-Acto knife to score both the smooth surface and the back of your piece first in order to give the glue some purchase.
Also, just a tip: it’s a good idea to mark exactly where your pieces have to be placed before any adhesives are involved. Super glue isn’t something you want to accidentally drip on your costume!
And that’s all there is to it! Again, if you need your pieces to be extremely durable, I’d recommend using urethane rubber or flexible resin instead of foam clay. However, if you’re knew to casting and want to experiment with a material that’s a little less expensive and more forgiving, this technique may be helpful!
As always, if you have any questions, please don’t hesitate to ask. May you ever walk in the light of the Crystal!