How to Use Paper Mache with Silicone Molds

We’ve written before about using ordinary objects as molds for paper mache, replicating objects from the outside. But what if you have a silicone craft or candy mold? Can you use it with paper mache? Let’s find out!

Can You Use Silicone Molds with Paper Mache?

There are so many beautiful silicone molds for crafting, soap-making, and candy making, and naturally many people are inspired to use them in their paper mache projects. Generally speaking, the BEST way to craft with a silicone mold is to use air-dry clay, which you can make yourself from a few simple ingredients. Air-dry clay is the best way to press into a mold, capture all the tiny details, and remove it cleanly.

Although air-dry clay is the best way to craft with silicone molds, you can also use paper clay and/or paper mache with silicone molds. Here are some recipes:

Note: Most of these recipes call for using an electric hand mixer or a blender, to make the mixing process faster and more consistent and get smooth results. If you use a blender, use a blender that you will devote to crafts and will no longer use for food. If you use a hand mixer, use a spare set of blades that you will set aside for crafts and won’t use for food. You can try mixing by hand instead, but it will take a lot of effort and the result will be less smooth and even.

DIY Paper Clay from Cellulose Fiber

If you want to make a lot of paper clay, cellulose fiber is a great material. It is sold at hardware stores as cellulose insulation, meant to be blown into attics and walls (note: make sure that you are choosing cellulose blown-in insulation, and not fiberglass). Because it’s meant as insulation, it’s only available in large bags, but it’s affordable, easy to use, and saves you time shredding your own paper. It is a favorite crafting material for many paper mache sculptors.

To make paper clay from cellulose fiber:

• Into a large bowl, add:
• 1/2 cup craft glue
• 1 cup flour
• 1/2 cup cornstarch
• 1 tablespoon salt
• Add water to start mixing
• Use an electric hand mixer and add water until the mixture is the consistency of smooth, thin batter, like a crepe batter
• Stir in a handful of cellulose insulation, then mix until smooth
• Keep stirring in small amounts of insulation and mixing until smooth, until the mixture is the consistency of clay and forms easily in the hand.

(For more on this style of paper mache, and the sculptures you can create, see this post from mache master Jonni Good)

DIY Paper Clay from Toilet Paper

Now that the toilet paper crisis of 2020 is over, it’s on the table again as a craft material. The advantage of toilet paper is that it breaks down quickly and easily, and you end up with a whiter surface that is easier to paint For this project, you want cheap, fibrous toilet paper without any lotions or additives.

To make paper clay from toilet paper:

• Remove the inner cardboard tube from a roll of toilet paper
• Soak the roll of toiled paper in a bowl of warm water
• When it is thoroughly wet and soggy, strain the toilet paper from the water
• Wrap the toilet paper in cheese cloth or a tea towel and squeeze out the water
• Place the damp toilet paper fibers in a large bowl
• Add to the bowl:
  • 100 grams of all-purpose flour
  • 100 grams of corn starch
  • 250 grams of joint compound
  • 150 grams of craft glue
  • 40 grams of olive oil, vegetable oil, or unscented baby oil
• Mix with a hand mixer until the mixture holds together and forms a smooth clay. You may need to add small amounts of water to reach the right consistency.

DIY Paper Clay from Egg Cartons

Egg cartons are one of the easiest and most versatile ways to make paper clay, and it’s a great way to make art from waste. You need to use rough paper egg cartons, without a smooth shiny finish.

To make paper clay from egg cartons:

• Tear the egg cartons into tiny pieces. Do not cut them: the torn edges will break down more quickly and easily
• Place the torn pieces into a large bowl
• Add enough hot water to cover the pieces
• Leave them to soak for several hours or overnight
• After soaking, knead the carton pieces into the water with your hands. Knead and combine until the mixture has the texture of oatmeal. If necessary, add a little more water, or drain off a little water. Make the mixture as smooth as possible (you may want to use a hand mixer to speed this up).
• Once you have a smooth, thick mixture, add a tablespoon of salt and mix it in
• Use a cheesecloth or tea towel to squeeze out any excess water
• Stir in craft glue until the final mixture is the consistency of clay

DIY Paper Clay from Shredded Paper

For this method, it’s best to use cheap, fibrous paper that breaks down easily. Uncoated newspaper or craft paper are good choices. To make paper clay from shredded paper:

• Tear the paper into pieces that are as small as possible
• Soak the paper in water overnight
• Add the paper and water to a blender, and blend until smooth (a blender is really necessary here, because the blades will chop the paper and mix it well)
• Use a tea towel or cheesecloth to squeeze out the excess water
• Proceed with either the “toilet paper” or “egg carton” methods above, using the shredded paper fibers in place of toilet paper or egg cartons

Using Paper Mache with Fine, Delicate Silicone Molds

All of these paper clay recipes are easy to make and easy to use with craft molds. However, all DIY paper clay tends to be a bit lumpy, unless you have a really great blender. If you have a mold with fine detail and delicate shapes, lumpy paper clay may not fit into those small gaps and capture all those details. Instead, I would try this approach:

• Make a paste that is 50% pastry or all-purpose flour and 50% cornstarch, with enough water to reach the consistency of thick cream: it should be smooth and flow, but also leave a fine coat on surfaces
• Tear very fine paper like single-ply toilet paper or tissue paper into very small pieces, the smaller the better
• Dip a paintbrush in the paste, use it to press the small pieces of paper into the mold
• Cover the entire inner surface of the mold, working slowly, using a small paint brush to press each little wet piece of paper into the details and contours of the mold
• Apply 3-5 layers of tissue or toilet paper, working delicately
• Once you have coated the inner surface of the mold with these careful layers of fine paper, you can fill in the rest of the mold with standard paper clay and a glue-based paste

The innermost layer of fine, small paper should capture all the details of the mold, and a starch-based paste should release cleanly. Using a lumpier paper clay to fill in the bulk of the mold saves time, and using a glue-based paste will bind the fine paper layer with the paper clay layer.

Tips for Using Paper Mache with Silicone Molds

It’s easy enough to make a paper paste and press it into a mold, but here are some key things to keep in mind:

• Plan ahead for a clean release. Most standard glues and adhesives won’t stick to silicone, so you can usually get a clean release. For the best release, use a starch-based paper mache paste (like flour or cornstarch and water), especially for surfaces or materials that will be pressed against the mold.
• Consider using baking spray. If you are using a silicone mold with epoxy, hot glue, or other stronger glues, and are concerned about getting a clean release, consider using a fine baking spray or coating the inside of the mold with a thin layer of vegetable oil using a paintbrush. This will slow down drying time, and you may want to consider how you will wipe the oil off the surface later if you want the finished object to accept some paints and adhesives.
• Let it dry COMPLETELY. Because there isn’t a lot of air circulation inside a mold, paper clays and paper maches will take longer to dry. In order to preserve the shape and detail of the mold, allow it to dry at least overnight.

While air-dry clay is the easiest and most consistent material to use for crafting with silicone molds, you can also use paper clay. Experiment with different methods and materials, and find what works best for you.