What Kind Of Glue Will Stick To Clay?

Gluing clay can be tricky due to its porous nature and flexibility when dry. While traditional adhesives like white glue don’t bond well to clay, specialty glues have been developed specifically for clay applications. Choosing the right glue depends on the type of clay you’re working with, whether it’s air-dry, polymer or oven-baked.

The two main types of modeling clay are air-dry and oven-bake. Air-dry clay, which includes brands like Crayola Model Magic, hardens through evaporation without baking. Polymer clays like Sculpey and Fimo require baking to harden. Each has unique properties that require a compatible adhesive to form strong bonds.

Gluing smooth, non-porous surfaces like glass and metal is straightforward. But clay’s uneven, absorbent texture makes adhesion more difficult. Finding the right glue can prevent breakage, especially for delicate clay pieces. The glue also needs flexibility when dry, rather than becoming rigid and brittle. This overview covers the best glues for the most popular modeling clays to help your creations last.

Properties of Clay

Clay is a unique material with properties that affect what kinds of glues will work best. The key properties of clay that impact gluing are:

Porosity

Clay is porous, meaning it has tiny holes throughout its surface. This porosity allows clay to absorb water and makes it difficult for some glues to penetrate the surface.

Absorbency

Due to its porosity, clay is highly absorbent. If too much water is added to clay, it can become saturated. This can prevent glues diluted in water from properly bonding to the clay.

Composition

Clay is composed of fine-grained minerals like silica and alumina. The chemical composition of clay determines its interactions with different types of adhesives.

Types of Clay

There are several main types of clay commonly used for crafting and sculpture:

Oil-Based Clays

Oil-based clays, also known as plasticine clay, are made from oils, waxes and fillers. They have a smooth, soft texture and remain malleable without drying out. Oil-based clays allow easy sculpting and shaping. Typical brands of oil-based clay include Plastalina and Van Aken Plastilina.

Polymer Clays

Polymer clays consist of synthetic polymers like PVC with fillers and plasticizers added. When cured in an oven, polymer clays harden permanently while retaining flexibility. Sculpey and Fimo are popular brands of polymer modeling clay. Polymer clays enable detailed modeling and come in a wide range of colors.

Air-Dry Clays

Air-dry clays are water-based clays that dry and harden at room temperature. They contain natural materials like cellulose fibers or starch mixed with minerals. Air-dry clays are inexpensive and easy to use. Brands like Crayola Model Magic and Activa Air-Dry Clay are designed especially for crafting and kids’ projects.

Choosing the Right Glue

When selecting a glue for clay, it’s important to consider the type of clay you are using as well as the strength of the bond required. Not all glues work well with every clay. The clay’s porosity and composition impact how well different adhesives will adhere. You also need to think about whether you require a flexible or rigid bond and if the pieces will undergo stress that could cause breakage.

For porous, air-drying clays like paperclay and Celluclay, white glue or PVA are good options. The glue is absorbed readily into the material for a strong bond. Epoxy resin can also work well for added durability and water resistance.

Premo Sculpey and FIMO are examples of polymer modeling clays that are oil-based. Cyanoacrylate glue, sometimes called super glue, works best on these non-porous materials. The thin super glue can penetrate smooth polymer clay surfaces and create powerful rigid bonds.

For pottery clays like natural terra cotta that you intend to bisque fire or glaze, it’s best to score and slip the surfaces while the clay is still soft. This wets the clay bodies so they combine together in a process called knitting. For earthenware clays, liquid clay slurry can also be applied. Avoid commercial glues that may burn or crack under high heat.

Think about the stress the glued piece will need to withstand. Weight bearing connections or parts subject to bending or frequent movement require the strongest glue choice for that clay type. Delicate assembly of decorative pieces may allow for weaker adhesives like white glue.

Cyanoacrylate Glues

Cyanoacrylate glues, commonly known as super glues, are fast-drying adhesives that form strong bonds with a wide variety of materials. Super glues cure rapidly when pressed into a thin layer between two surfaces. The cyanoacrylate monomers in the glue quickly polymerize, or link together into long chains, upon contact with moisture in the air.

Super glues offer several benefits when used with clay:

• They form an instant, tight bond that can be used to join clay pieces or attach clay to other materials.
• The thin consistency allows the glue to spread easily into clay’s porous surface.
• They work on most types of modeling and air-dry polymer clays.
• Most super glue brands are non-toxic once fully cured.

Potential downsides of super glues include:

• The bonds may weaken over time, especially with exposure to moisture.
• Super glues can leave behind a shiny, glossy look on clay’s surface.
• They cannot be reactivated or reversed once dried.
• Some cheaper brands may not create as strong of a bond.

Popular cyanoacrylate glue brands for clay work include Loctite Super Glue, Gorilla Super Glue, and E-6000. It’s best to choose one designed for bonding porous materials that will work on both clay and other craft surfaces.

Epoxy Resins

Epoxy resins are a popular two-part glue used for many arts and crafts projects. They come in two separate containers – a resin and a hardener. When mixed together in the proper ratio, the components undergo a chemical reaction that causes them to harden into a durable, rigid plastic material that strongly bonds to clay.

Epoxy resins are valued for their long cure times, which allow you to properly position pieces before the bond sets. Cure times vary by brand, but average around 24 hours at room temperature. The curing process generates heat, so some epoxies cure faster and stronger when left to set overnight. Speeding up cures by applying heat can result in weaker bonds.

Once cured, epoxy resins form an extremely strong, waterproof bond that can be sanded, drilled, and painted. The strength comes from the cross-linking molecular structure that forms as the epoxy cures. This makes epoxies a great choice when you need to glue clay components that will withstand heavy use or forces from multiple directions.

White Glue

White glue, also known as PVA (polyvinyl acetate) glue, is a common household adhesive made from polyvinyl acetate resin emulsified in water. PVA glue is white in color when wet, but dries clear and colorless.

One of the benefits of using PVA glue with clay is its flexibility when fully cured. While PVA glues are moderately rigid when wet, they become quite flexible, elastic and somewhat rubbery when completely dry. This makes PVA a good choice for bonding clay pieces that may flex or bend when handled or moved. The flexibility prevents the clay from cracking at the glue joint.

Another advantage of white PVA glue is its very low cost compared to specialty clay adhesives. PVA glues can be purchased at any hardware store or arts & crafts retailer in large bottles for just a few dollars. The affordable price and widespread availability makes white glue an economical option for most crafters and artists working with clay.

Hot Glue

Hot glue is another type of adhesive that can be effective for bonding clay. Hot glue guns melt solid glue sticks and apply the melted adhesive to surfaces. When the glue cools and hardens, it creates a strong temporary bond. Here are some key points about using hot glue with clay:

• Hot glue forms fast, temporary bonds. The bonds may weaken or fail over time, so it is not suitable for pieces that need to endure stress or high impacts.
• The glue dries very quickly, often in under a minute. This allows you to work fast and attach clay pieces rapidly.
• Use low-temperature hot glue formulated for crafts. High-temperature industrial hot glue can burn or scorch clay.
• Apply hot glue sparingly to avoid drips. Press surfaces together firmly while the glue is still molten.
• Glue guns allow you to control where and how much glue is applied. This makes hot glue good for attaching clay decorations or fastening pieces together temporarily.

With its rapid drying and ability to quickly tack pieces together, hot glue is handy for clay projects requiring temporary assemblies or small decorative attachments. Just take care not to overheat or burn the clay.

Applying the Glue

Gluing clay requires some preparation of the clay surface and care when applying the glue. Here are some tips for getting the best bond between clay surfaces:

Surface Preparation

Make sure clay surfaces are clean and free of dust before gluing. Wipe with a damp cloth or paper towel to remove any debris. Allow surfaces to dry completely before applying glue.

Avoiding Messes

Work on a protected surface like wax paper or parchment to avoid getting glue on your work table. Apply glue carefully to avoid drips and spills which can permanently stain surfaces. Have paper towels handy to wipe up any excess glue.

Clamping

After applying glue, clamp glued clay surfaces together by using clothespins, vices, or specialty clay clamps. Apply firm, even pressure across the joint to help force glue into the clay for maximum bonding. Allow glue to cure fully before removing clamps.

Conclusions

Finding the ideal glue to work with clay depends on a number of factors, including the type and hardness of the clay, as well as how long you need the bond to last. Several common glues work well for clay crafting and repairs.

Of all the options, epoxy resin produces the most durable bond, capable of withstanding high stress and heat. However, it takes more skill to work with and requires resting time for the epoxy to set up. Cyanoacrylate glue offers quick-setting ‘super glue’ strength ideal for mends, but is less effective on porous clay. For most crafting applications, white glue gives you a strong bond with plenty of working time. Hot glue adheres fast, but has a thick texture and is best for only temporary clay bonds.

To ensure the strongest connection, always follow the glue manufacturer’s instructions for proper application and drying time. Assess the intended use for your clay project, and select the appropriate glue for the type of clay, the bond strength needed, and how quickly you need the adhesive to set.