Tutorial - Natural polymer starch masks

Updated 1/17/2020

How to Make the Natural Polymer Starch*:

1 1/2 cups of water
6 Tbs cornstarch**
2 Tbs white vinegar
2 Tbs vegetable glycerin
  1. Add all ingredients to saucepan and stir together until all clumps are dissolved.
  2. Turn on heat to medium, and keep stirring mixture to prevent from sticking on the bottom.
  3. After a few minutes, once the mixture is translucent and scoopable, turn off stove and remove mixture from heat.
*Recipe based on  DIY Bio-plastics instructions at http://www.instructables.com/id/DIY-Bio-plastics
**This recipe should be adaptable to using other forms of starch such as rice starch.

How to Make the Masks:

These masks are made from biodegradable, natural materials, including recycled coffee sacks. Any waste generated by the process of making them should be fully compostable. But keep the masks away from rain and high humidity, unless you are ready to compost them too!

Old coffee sacks may be obtained for free from coffee distribution warehouses.
Interesting fact: Coffee sacks are typically woven from natural materials sourced at the same part of the world that the coffee beans were grown.

Find a form to build your mask over. If you have done mask-making before, you may have made a plaster cast of your face. While that would be ideal, you can also improvise with a foam wig head laid on its back. Or cut a 1 gallon vinegar bottle in half from top to bottom, so the portion without the handle will lie flat on the worktable.

Customize the mask form with oil clay. Change the nose, give it a beak, etc. But don't get too detailed, you just want broad surfaces that will support the shaped burlap as it dries. Avoid sculpting undercuts that would make the mask difficult to remove from the form.

(See recipe above).

Cut the burlap. 12x12" to 14x14" square is a good size to start with if you want to figure out the shape as you go. Lay the burlap piece out on your work table and use a 1" or 2" brush to apply the starch mixture onto what will be the underside of the mask. Then flip the burlap over and place it diagonally onto the mask form.

Arrange the burlap on the mask form. I recommend using the burlap on the bias (diagonally) as it seems to make it easier to shape. Start from the highest point of the mask form, (typically the nose or beak), arranging folds and creases and hollows so that they radiate from the high point out to the edge of the form. Folds and ridges will add strength to the mask and help it hold its shape. (If you choose not to add many folds or ridges, you may need to reinforce the edges of the mask after it is dry, by stitching on wire or basketry material).

Burlap edges can be trimmed off, but if you have extra material it can be nice to use it as a "hem" you fold underneath. (Before you fold it over, make sure there is enough starch mixture on the edge to stick the layers together).

While pinching and shaping and pining the burlap into position, you should also brush more starch mixture on to the top of the mask--it helps stick everything in place. Try to avoid leaving gloppy lumps if you can, just use your brush or fingers to remove, or just smooth any lumps into the weave of the burlap.

Use T-pins or sewing pins to hold things in place while the mask dries. (Foam wig head users can just poke their pins right into the head).

Set the mask in the sun or in front of a fan for a few hours. (If you are using oil clay, be careful that the sun doesn't get hot enough to melt the clay).

When the burlap feels stiff and mostly dry, you can carefully peel burlap off the form. This is the scariest part! Parts of the mask may turn inside out, but AS LONG AS THE MASK IS DRY ENOUGH, you should be able to carefully push everything back into the right shape after it comes off. If however, you find that the mask seems too damp underneath peel off successfully, just set it back in the sun (or by the fan) for longer, then try again later.

8) ADDITIONAL STARCH LAYER, AND FINAL DRYING: Once the mask is off the mold, you should coat the inside with one more layer of starch mixture, taking care to smooth any edges and fill in hollows and cracks. Then you will need to dry it again, but this time you have the super-fast option of using your oven to dry it! I use the lowest setting (170 degrees) and set the masks on cookie sheets. Once it is dry, you have the option of brushing on one more starch coat on the outside, then drying it one more time using the oven, sun or fan.

So many options! Here are a few suggestions:
  • Embroider or stitch details onto the burlap fabric with naturally died or colored wool yarn or cotton, jute cord, etc.
  • Apply paper mache over the mask with natural paper, using the polymer starch mixture as a glue and finish.
  • Mix some more polymer starch and combine with  recycled paper fiber, such as Celluclay. Add this to the mask surface as a detail or texture coat.
  • Paint the mask with natural, biodegradable paints. (Flexible pigment binder recommended, such as methyl cellulose AKA Elmer's Art Paste, or gelatin).
  • Stitch on wooden or bone beads, feathers, natural fabrics, etc.

The mask should be very light, so may not need to be tied very tightly to stay on, or need to be padded. I like to use a leather punch to make two holes on each side, a little higher than eye level, so that the mask is supported by the temples or forehead more than the nose or ears. Two lengths of leather thong or ribbon can then be threaded through the holes so there are two separate ties going around the head.

Happy mask-making!


  1. Couple of questions: does your starch glue keep if you put it in a jar in the fridge?
    Will it harden as it cools even if it’s in a jar?
    At the end, you suggest gelatin with pigments to make paint?! What are those proportions?

  2. Hi Adriene,

    In a cool environment, the polymer starch paste can last for a month or more in a sealed container without growing mold. But you may find that it can eventually develop a slightly fermented smell, which refrigerating would delay.

    The most important factor with using an old batch is that the mixture seems to depolymerize as it sits while the water and starch slowly separate from on another. A solution to that is to put it all back in a saucepan and gently reheat while stirring, until the water and starch recombine and the mixture becomes gel-like again. (You can also add a small amount of extra water to the saucepan if the starch paste seems thicker than when you originally made it)

    The polymer starch mixture does stiffen when it cools. But it does not actually become hard unless it left to dry out completely. The more thinly it is applied the faster it will harden. Evaporation is what causes it to dry out/harden.

    For the gelatin paint, I am mixing the gelatin according to the directions for gelatin glue at https://www.thehippyhomemaker.com/gettin-sticky-with-it-homemade-glue-paste/ (except I just use regular Knox brand gelatin, and clove oil to preserve). Once you have a jar of warm/liquid gelatin glue on hand, you can spoon small amounts of that into smaller jars, then add powdered pigment and a little hot water if necessary and stir with a paintbrush until it seems like a good consistency to apply.

    You want the gelatin glue/paint to stay warm while you are painting. The simplest option is to place your jars in a container holding 1-2" of hot water, changing cooled water out for more hot water as needed. Or you could place the jars in a crock-pot containing 1-2" of hot water, or place the jars in a metal baking pan (containing 1-2" of hot water) on an electric griddle. The paint in the jars will dry out quickly, so add more water and stir as needed. And you may have the best results if you apply multiple thin layers of paint to your project (allowing each layer to dry/set in-between applications) instead of just one thick layer.

    I hope this helps, and good luck! I would love to see your finished project.