Modifying plastic festival masks

Princess Peach with a Boo festival mask

Every so often, you’ll find a character to cosplay that wears a festival mask on their head. Aside from a typical kitsune festival mask, you might have trouble finding a mask that suits your needs, and that wasn’t any different when I was trying to find a Boo mask for a Princess Peach cosplay. No matter how hard I searched, I never could find one. No official merchandise or premade I could purchase on eBay or Etsy.

So I thought about making one, but I needed a base that wasn’t expensive but also would be round enough for a boo. And that’s when I found plastic emoji masks.

You can find all sorts of emoji and other cheap masks for about $5 on eBay and they work great for festival masks. They’re a cheap papery plastic with a loose string. They’re easy to work with and take to glue and paint pretty well. You can cut them and restring them as well.

You can also find craft masks that are made out of a more papery material.

Emoji mask at the start (left) with the finished Boo mask (right)
Original emoji to a boo mask

For my boo mask, I went with a round smiling emoji since it matched the shape pretty accurately. For your project, pick out a mask that is close enough to the shape you want to make.

Skill level: beginner-friendly

Budget level: budget-friendly!

Supply list:

  • A festival mask
  • Sandpaper, 220 grit sheet (if your mask is plasticky)
  • Paintbrush
  • Paper or poster board for patterns (if desired)
  • 2mm fun foamies
  • Primer such as Mod Podge, flexbond, or other plastic-friendly primers
  • White acrylic paint
  • Acrylic paints in colors. $1 paints are fine.
  • High gloss sealant. I prefer DecoArt Gloss or High Gloss sealant
  • Lightweight air-dry foam like foam clay or Fimo (optional if you’re adding accents like boo arms or a tail)
  • Glue. I use quick dry superglue but you could use any glue that doesn’t require clamping and works on plastics
  • Masking tape (optional)


Cheap plastic masks often have a sheen to them, a top layer that protects the cheap coloring job. The problem with this layer is that acrylics do not like this layer, so you’ll have to sand it off. Plastic is surprisingly delicate when it comes to sanding. Too rough a grit, the plastic will chip off. Too fine a grit, and the sanding will do nothing. 220ish grit seems to be a pretty good sweet spot.

The plastic mask getting sanded. I think it's judging me
It’s judging me while I sand its face off

When sanding, you’ll want to sand over a cleanable surface, a garbage can, or outside to keep the dust from going everywhere.

Cut a strip of sandpaper off, large enough to hold easily with your hand. Rub the sandpaper against the mask. You don’t need to be aggressive with it. This layer comes off pretty easily. This mask is pretty cheap after all.

As you sand, you may notice that the mask starts losing its color and staining the sandpaper. This is honestly expected with how cheaply the mask is made. Keep sanding until the entire mask is scuffed up.

Once the mask is sufficiently scuffed, it’s time to add accents.

Adding details

Now’s the fun part. Details! This section talks about adding simple details, but if you’re the crafty sort, go ham. Add all sorts of sculpted details! Lightweight air-dry clay is optimal for something like this. Air-dry lightweight Fimo, paper clay, and foam clay are your best options and are pretty easy to work with. You could also use paper mache to make any structural changes.

But let’s talk simple details to get started. For my boo mask, I didn’t need anything fancy, just accents, and what better way to add details than 2mm foamies. You can find them in packs for super cheap at Walmart and craft stores in many colors. Since we’ll be painting over them, color doesn’t matter particularly.

Creating the pattern for the arm and tail details for the Boo

I’m the sort of pattern twice, cut once crafter, so I made a template first. You can use scrap paper or poster board to draw your detail shapes. Paper is more flexible than foam is, so you can get the exact size for edges that you need before cutting the foam pieces.

For boo, I cut an arm, the tail, the eyebrows, and the teeth out. This let me test to make sure the foam would cover the mask’s teeth and the top of the eyes, since boos have lowered eyebrows.

Once you’re satisfied with the template, cut out the foamies. It’s time to glue. I use superglue, and if you do the same, make sure not to glue for long periods of time. Smelling too much superglue makes your sinuses feel like they’re burning.

Gluing the foam details on the mask. I think it's laughing at me.
I think he’s still laughing at me

When gluing the pieces down, make sure not to glue the mask string. You’ll want it to still be useable. Optionally, you can block the eyeholes from the inside to cover them up.

If you’ve glued pieces to the outside edge, you may notice gaps forming. This is where the air-dry clay comes in. Squish some clay into the gaps that have formed to fill them in. Some clays such as foam clay will let you smooth them out with some water. Others such as paper clay can be smoothed out with the back of a spoon.

Let the mask sit. Superglue requires about 12-24 hours to fully cure, even the instant stuff. If you’ve used clay, check how long it takes to dry. it’s usually about the same amount.


Before you paint, you’ll want to prime the foam and the plastic. Foam is porous by nature, and it will slurp the paint up. So in order to have a nice painted layer, you’ll want a good primer to start. Brush the primer on with a wide paintbrush, making sure that the primer is evenly applied. If the primer starts to pool in any of the details, use your brush to spread the primer around and distribute it elsewhere.

Use about 2-3 layers to fully prime the surface and ensure that you didn’t miss any spots.

Painting the base coat completely white to make the mask look more plasticky

Part of priming is applying a solid color base coat. Base coats are generally white or black, and that color affects the painted layers on top. Since we want the mask to look like a plastic festival mask, use a white coat. This makes the top colors appear to be brighter and more plasticky.

Paint the entire mask white with a wide brush. Foam, mask, and all. Even if things are already white. This will give you a consistent, even color when working on the topcoats and cover up any pen markings or stray glue spots.

White is notoriously bad at covering things up, so to get a solid white coat, you’ll need a few layers, especially if you have dark accents on your mask like the mouth and eyes in mine. Make sure to get the sides of the raised details as well so you don’t have any unwanted foam color sticking out the side.


Masking is optional here. I’m a messy painter sometimes so I tend to mask to make it easier on myself and not have to do as many touchups in the end.

Masking is the process of using masking or painter’s tape to protect sections you don’t want to paint. When dealing with curved sections, you can tear strips of tape and place them down along the curve piece by piece. Straight lines are easy since you just need to lay down a piece of tape and be done with it.

Masking off sections that won't be painted
That sure is a funny goatee

I only masked around the eyebrows and edges of the mouth since I knew I’d be doing detailing around the teeth and eyes. It was easier to reach the side edge of the eyebrow with the masking tape on as well.

Once you’ve masked off sections or just skipped this part, it’s time to paint. You may want a smaller paintbrush for this, just to make sure you’re not sloshing paint all over the place and getting black where you want white or red to be.

Paint each color one by one, allowing each color and coat to dry in between. Once you’ve painted the color, slowly remove the masking tape, careful not to pull the paint up with it.

Now are touchups, Even with masking, you may need to touch up sections where the paint hit a corner of the tape or got underneath it. Take a small brush and touch up any colors that may have bled into the wrong section. If you’re covering up black or other dark colors, it may take two coats to get a lighter color to properly cover it.


Like with any paint job, you want to seal your paint to protect it. Cons are notoriously harsh on any paint job, and one little scrape could ruin all your paint.

Sealant can also give the mask the high-gloss appearance it needs to look more like a plastic festival mask. This works even with matte acrylics and makes them super shiny. It also evens out the difference between matte and glossy paints so they both look shiny.

Like with the primer, brush the sealant on over the entire mask. Use a wide soft brush to make sure you don’t scratch your paint job. You can use a makeup or painting sponge. Apply 2-3 layers of sealant to ensure the mask has a nice even gloss to it.

Finished Boo mask
He’s happy to be finished

And there you have it! Now you too can make your own custom festival mask without breaking the bank. It’s easy to pack and super lightweight. You can use the string or glue clips onto the back of the mask to tuck into your hair or wig.

I hope this helps with making your own masks! If you make one with this tutorial, let me know. @ me on social media so I can like and admire your work!

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