Is Foam Clay Waterproof When Dry?

What is Foam Clay?

Foam clay, also known as polyclay, is a lightweight modeling material made primarily from polyvinyl chloride (PVC). Unlike traditional clays like polymer or ceramic clay, foam clay contains no clay minerals. The main ingredients in foam clay are:

• Polyvinyl chloride (PVC)
• Plasticizers
• Color pigments

Polyvinyl chloride gives foam clay its lightweight, spongy texture. Plasticizers keep the material flexible and workable. Pigments are added to create a variety of bright, vibrant colors.

The lightweight, airy texture sets foam clay apart from traditional clays. It is also softer and easier to condition than polymer or ceramic clays. Foam clay doesn’t harden like other clays and will maintain its lightweight, squishy texture even when dry. This makes foam clay a unique, fun material for crafting and modeling.

Making Foam Clay Models

Foam clay is an easy, fun material to shape into creative sculptures, characters, decor items and more. Here are some tips for sculpting and hardening your foam clay creations:

Shaping and Sculpting Techniques

Foam clay can be shaped and molded with your hands. Warming the clay makes it softer and more pliable. Roll pieces into balls or logs, pinch off bits to make shapes, and smooth and blend the clay together. Use sculpting tools like wooden or silicone clay shaping tools to add texture and refine details.

Tools Used

In addition to your hands, use sculpting and shaping tools like:

• Clay sculpting sticks and loops
• Modeling tools
• Clay rollers and cutters
• Plastic or wood knifes and skewers
• Cookie cutters or punches for shapes

Baking to Harden

After sculpting, foam clay models need to be hardened either by air drying or baking in the oven. Follow package instructions for baking temperature and times. Baking makes the models fully hardened and durable. Let cool completely before handling.

Is Foam Clay Waterproof?

The waterproof qualities of foam clay depend on whether the clay has been baked to harden it or is still in its soft, pliable state.

Unbaked foam clay is not water resistant. When exposed to water, unhardened foam clay will become sticky as the water is absorbed into the clay. Prolonged contact with water can cause unbaked foam clay sculptures to soften, lose their shape, and become mushy. Immersing unfired foam clay in water is not recommended.

However, once foam clay has been cured and hardened in the oven or air dried, it becomes water resistant and waterproof. The baking process chemically alters the clay, creating a durable material that will not dissolve when interacting with water.

Hardened foam clay items can get wet without damage. Light rain, splashes, or brief contact with water will not affect baked foam clay models or crafts. Fully submerging hardened foam clay in water for extended periods is still not recommended, but normal indoor exposure to water droplets or humidity after baking will not ruin foam clay creations.

In summary, unbaked foam clay and water do not mix well, but once hardened through heat curing, foam clay obtains waterproof properties ideal for both indoor and outdoor use.

Using Sealants and Varnishes

One of the best ways to improve the water resistance of foam clay creations is to apply a protective sealant or varnish. There are several options that work well with foam clay:

Acrylic Spray Sealer – Acrylic sealers come in both spray and brush-on formats. The spray options allow for quick, even coverage. Acrylic forms a flexible barrier that will help protect foam clay from moisture.

Polyurethane – Polyurethane is a common wood and craft sealant. It dries to a hard, durable finish that resists moisture. Multiple coats can be applied for maximum protection.

Epoxy Resin – Epoxy is extremely waterproof and is commonly used to seal crafts for outdoor use. It will fully encapsulate the foam clay in a clear, glass-like coating.

Mod Podge – Mod Podge now makes an Outdoor variety designed to protect crafts from weathering. It goes on white but dries clear.

When applying any sealant, make sure to cover the entire surface of the foam clay, including any crevices and undersides. Let the sealant fully cure as directed before exposing the item to moisture. Reapply annually for upkeep.

Outdoor Use Considerations

When using foam clay for outdoor projects, it’s important to consider the durability and longevity of the material in outdoor environments. While foam clay can be quite durable compared to other clays, there are some factors to keep in mind:

Temperature and Sunlight Exposure: Like many materials, foam clay can be impacted by extreme temperatures and sunlight over time. High heat can cause foam clay to soften, distort or discolor. Prolonged sunlight exposure can also cause fading or discoloration of the clay. These effects happen gradually, but can impact the longevity of outdoor foam clay projects.

Waterproofing Over Time: Foam clay starts out inherently waterproof when fully cured, meaning light rain or splashes won’t immediately damage it. However, when used outdoors for extended periods, the waterproofing can wear down over years of exposure to elements. Using protective clear coatings can help prolong water resistance.

For any outdoor foam clay projects where you want the creation to last as long as possible, take precautions like avoiding full sun exposure, using UV-resistant paints, and applying outdoor-safe varnishes or sealants. Rotate or refresh outdoor pieces periodically for best results.

Indoor vs. Outdoor Foam Clay Projects

Foam clay is a versatile crafting material that can be used to create both indoor and outdoor projects. However, there are some important considerations when deciding whether your foam clay creation is suitable for outdoor display.

In general, foam clay is best suited for indoor crafts and decorations. Pieces made with foam clay will hold up well inside your home or classroom when kept away from moisture. Some great ideas for indoor foam clay projects include:

• Ornaments and decorative pieces for shelves or tabletops
• Magnets made from shaped foam clay
• Foam clay jewelry like beads, pendants and earrings
• Miniature figurines, animals or food items
• Foam clay bowls, vases and cups

If you want to use foam clay for outdoor projects, it’s important to take additional steps to waterproof and seal the pieces. Here are some tips:

• Use an acrylic sealer or UV-resistant polyurethane to seal foam clay before displaying outdoors.
• Avoid placing foam clay outside during rainy or damp weather.
• Bring foam clay pieces indoors during winter or store in a covered area.
• For prolonged outdoor use, build an armature or frame using wire and seal foam clay over top.
• Look for outdoor-safe foam clay alternatives like air-dry porcelain clay.

With proper sealing and care, you can expand the possibilities for your foam clay crafts. Just be mindful of moisture and weather exposure when deciding if a project should stay indoors or not.

Storing Foam Clay Correctly

Properly storing foam clay is essential to maintain its useful properties and prevent it from drying out or becoming damaged. Here are some tips for keeping your foam clay in ideal condition:

Store foam clay in an airtight plastic bag or container. Exposure to air will cause foam clay to dry out. Make sure to squeeze all the air out before sealing the bag or container.

Keep foam clay out of direct sunlight, which can also cause drying. Store in a cool, dark place like a cupboard or drawer.

Consider adding a small piece of damp paper towel to the storage bag or container. This will help keep the clay moist and malleable.

If storing foam clay for more than a few weeks, check on it periodically. If it starts to dry out, knead in a little water until it regains a soft, pliable texture.

After using foam clay, seal it back in the airtight bag so it doesn’t dry out. Knead it briefly to bring it back to an even, smooth consistency before storing.

Avoid storing foam clay in extreme cold or heat, which can affect its texture and workability. Ideal storage temperature is around room temperature.

With proper storage methods, foam clay can retain its flexibility and molding properties for months. Just be sure to keep it sealed from air exposure and temperature extremes.

Fun Foam Clay Craft Ideas

Foam clay is a versatile medium that can be used for both decorative and functional crafts. Here are some creative foam clay modeling ideas:

Jewelry

Make custom beads, pendants, and charms with foam clay. Let the pieces dry fully, then paint and seal them. String them together to create unique jewelry sets.

Magnets

Sculpt creatures, food items, letters or shapes with foam clay and glue a magnet on the back. These make great gifts or can be used to decorate fridges and other magnetic surfaces.

Miniatures

Construct tiny models of animals, people, buildings, vehicles and more. These imaginative little scenes come alive when painted.

Ornaments

Get creative with holiday decor by making tree ornaments out of foam clay. Let them dry fully before threading a ribbon through to hang up. Paint fun patterns or designs on each one.

Keychains

Press a key ring or chain into the top before baking foam clay sculptures to make into keychains. Make names, animals or abstract shapes for custom carry-along art.

Pros and Cons of Foam Clay

Foam clay has both advantages and disadvantages compared to other modeling clays.

Advantages of Foam Clay

Some of the key benefits of using foam clay include:

• Lightweight and easy to handle
• Does not dry out when exposed to air
• Available in wide range of bright colors
• Soft and malleable texture
• Easy to blend and mix colors
• Affordable and accessible
• Makes no mess

The lightweight, soft texture of foam clay makes it very easy to shape and mold detailed objects, characters or sculptures. It doesn’t crumble or crack like some clays, allowing for fine detailing with fingers, sculpting tools or cutters. The clay doesn’t dry out when left uncovered, so projects can be worked on over multiple sessions.

Disadvantages of Foam Clay

Some potential disadvantages of foam clay include:

• Can be less durable for functional items
• Finicky for very precise sculpting
• Not good for baking/firing/air-drying
• Can be messy/sticky when warm
• Doesn’t bond well to itself
• Can’t achieve same level of realism as polymer clay

Foam clay may not be ideal for sculptures or models requiring extreme precision and definition. It can’t be hardened through baking or firing like some clays. Pieces made from foam clay remain lightweight and fragile after drying, rather than becoming hardened and durable.

Frequently Asked Questions

Here are some common questions about working with foam clay:

Is foam clay waterproof?

Foam clay is not waterproof in its original state. However, once baked or sealed with a liquid sealant, it becomes water-resistant and can be used for outdoor projects or those involving water contact.

Should I bake foam clay creations?

Baking is recommended to harden foam clay and make it more durable. Bake pieces at 225°F for 10-15 minutes. Baking also makes the clay water-resistant.

How should I store unused foam clay?

To maintain its texture and pliability, unused foam clay should be stored in an airtight container or plastic bag. Keep it away from direct sunlight and extreme temperatures.

Can foam clay be used for jewelry?

Yes, foam clay works well for making lightweight jewelry like beads and pendants. Apply a sealant first to harden the clay. Pieces may need re-sealing over time if worn frequently.

Is foam clay toxic?

Foam clay is non-toxic, making it safe for kids. It’s made from a polyethylene material that is free of common allergens. Supervise young children to avoid accidental ingestion.