How Thick Should Clay Be For Ornaments?

When creating clay ornaments, one of the most important considerations is the thickness of the clay you use. The thickness impacts the strength, weight, drying time, and overall look of the finished pieces. Selecting the right thickness can be the difference between creating stunning ornaments that proudly adorn the tree versus flimsy decorations that easily chip or crack. Taking the time to understand how thickness impacts the ornament creation process will ensure your handcrafted clay designs stand the test of time.

Recommended Thickness

When making ornamental clay pieces, the generally recommended thickness is between 1/4 inch (6mm) to 1/2 inch (12mm). This provides a good balance between strength, minimizing excess weight, and allowing adequate drying.

Thinner pieces under 1/4 inch can be prone to cracking or breaking easily. Pieces thicker than 1/2 inch will be unnecessarily heavy, require excess clay, and take longer to dry and fire properly. They may also develop cracks or explode in the kiln.

For most ornamental pieces, aim for a thickness between 1/4 to 1/2 inch for ideal results. Consider the size and shape of the ornament. Larger pieces may need to be toward the thicker end while smaller pieces can be at the thinner end of the range.

Thickness for Strength

When making ornaments or any clay objects, thickness is an important factor for structural integrity and strength. Thinner pieces of clay are more fragile and prone to breakage, while thicker clay is sturdier.

For ornaments, a good rule of thumb is that the thickness should be proportional to the size. Small ornaments like Christmas tree ornaments or earrings can be relatively thin at 1/8″ thick or less. However, larger ornaments or decorative pieces should be thicker to support their weight without cracking or breaking. A thickness of 1/4″ – 1/2″ is recommended for medium sized ornaments 3″-6″ in diameter. For very large decorative pieces over 6″ wide, a thickness over 1/2″ – 3/4″ thick or more may be needed.

The strength of clay also depends on the type of clay used. Air dry clays are rather delicate even when made thicker, while polymer and oven-baked clays can be made thinner but still remain sturdy. Regardless of clay type, pieces that are too thin lack adequate structural support while excessively thick pieces may crack from prolonged drying and firing. Testing different thicknesses with the clay type and size of ornament is recommended to find the optimal balance of strength versus weight.

Consider Weight

The thickness of your clay pieces will directly impact how much they weigh when completed. Thicker clay results in heavier finished pieces. This is an important factor to keep in mind depending on your plans for the finished ornaments.

For ornaments that will be hung on a tree or in a window, a lighter weight is often preferable. Thinner clay in the 2-3mm range will result in lightweight ornaments that won’t heavily droop down branches or suction cups. Aim for a thinner clay thickness if you want to create delicate ornaments.

Heavier ornaments can be achieved with thicker clay in the 4-6mm+ range. These make nice shelf sitter ornaments that don’t require hanging. Thicker clay ornaments also tend to be more durable and resistant to breakage if they take a fall.

Consider the display location and durability needs when deciding on clay thickness. Test different thicknesses to find the right balance of weight and strength for your specific ornament designs.

Firing and Drying Clay Pieces

The thickness of your clay pieces will impact how long they take to properly dry and fire in a kiln. Thicker clay takes more time to dry evenly throughout. If thick clay pieces are fired before being fully dried, the moisture trapped inside can turn to steam and potentially crack or explode the piece.

As a general guideline, allow 1 week of drying time per 1/4 inch thickness of clay. So a 1/2 inch piece should dry for 2 weeks before firing. Thicker pieces may require much longer, up to several weeks or months, to thoroughly dry. Using a kiln to slowly pre-heat and dry very thick clay pieces can help avoid cracking before the final firing.

During firing in a kiln, thicker clay also requires more time for the heat to fully penetrate to the center of the piece. A good rule of thumb is to fire for 1 hour per 1/4 inch thickness at the recommended temperature. Firing too quickly can result in the outside glazing and hardening while the inner clay remains under-fired and prone to slumping or cracking. Be sure to use an accurate kiln thermometer and adequate firing time for the thickness of your pieces.

Level of Detail

The thickness of the clay can significantly impact the fineness and intricacy of details that can be sculpted into ornaments. Thinner clay allows for more delicate, refined, and intricate detailing, as the clay is more pliable and movable. With thinner clay, artists can create very fine patterns, textures, and sculpted elements.

However, as the clay thickness increases, the level of detail that can be reasonably achieved decreases. Thick clay can be too unyielding to sculpt very fine details without distortion or damage occurring. The details end up being more thick and bulky. Intricate patterns or textures become blurred or indistinguishable at thicker dimensions. Therefore, more simplistic, bold, and large-scale details are recommended for thicker clay ornaments to ensure the details hold their shape and definition.

When deciding on clay thickness, artists should assess the complexity and fineness of details needed for their design. Delicate filigree patterns, tiny sculpted elements, and refined textures require working with thinner clay. More substantial, bulky details can be sculpted from thicker clay. The level of detail correlates closely with the clay thickness.

Types of Clay

The type of clay used can impact the ideal thickness for ornaments. Here are some key differences between clay types:

Polymer Clay – Polymer clay can be rolled very thin, even as thin as 1/8 inch. It has high strength and flexibility when cured, so it can withstand thin areas. Polymerclay is best for highly detailed ornaments.

Earthenware – For earthenware clay, aim for 1/4 inch thickness minimum. Earthenware is prone to cracking and chipping if rolled too thin. Sturdier earthenware ornaments require thicker clay.

Stoneware – Stoneware has high durability and can be rolled to 1/8 inch thickness. The high firing temperature gives it strength while thin. Well-suited for delicate ornaments.

Porcelain – Porcelain can be rolled thinly to 1/16 inch while maintaining strength. It’s highly elastic and won’t easily warp or crack. Ideal for very intricate porcelain ornaments.

Test different thicknesses when using a new clay to ensure it has adequate strength once fired and dried. The thickness guidelines may vary across specific clay products and formulas.

Tools and Techniques

When working with thicker clay, it’s important to have the right tools to handle and shape it. Here are some tips for working with thicker clay:

Rolling Pin – A long, sturdy rolling pin without handles works best to roll out thick clay evenly. Acrylic rods can also be used.

Texture Tools – Clay tools with ridges, patterns and textures are useful for adding detail and dimension to thicker clay pieces.

Cutting Tools – Stiff metal clay blades or specialty clay cutters allow you to cut clean edges in thicker clay.

Molds – Press molds and texture mats make it easier to achieve shapes and patterns.

Armature – For large or heavy sculptures, build an armature from wire, foil or other materials to support the weight of the clay.

Water & Oil – Lightly wet or oil clay tools to prevent sticking when working with thick clay. Don’t over-wet the clay itself.

Kneading – Take time to properly knead thick clay to improve its elasticity before attempting to sculpt or shape it.

Support – Rest large pieces in your lap or on a foam pad while sculpting to avoid hand strain.

Troubleshooting

If your clay is too thin, there are a few issues that may arise during the creation and firing process. Here are some common problems and solutions:

Cracking or breaking: Thin areas are prone to cracking or breaking, especially at points like arms, legs, tails, or other protrusions. Using clay that is thick enough provides strength and durability. If cracking occurs, avoid handling the piece much and let it fully dry before firing. Extra supports could help brace weak areas.

Warping or slumping: Without enough thickness, clay can warp or slump in the heat of firing. Make sure to maintain an even thickness throughout to prevent some parts from becoming thinner than others. Prop or support pieces in the kiln to limit warping. Improve clay consistency and let dry fully before firing.

Losing detail: Intricate shapes, patterns and details need adequate thickness to hold their form, both when sculpting and firing. If too thin, they can get distorted. Use thicker clay and sculpt details a bit more prominently at first, as some shrinking will occur.

Increasing the overall thickness just slightly can avoid many of these issues. Support fragile areas with extra clay, armatures or braces. Letting pieces dry slowly and completely before firing also helps maintain the original shapes when fired.

Conclusion

When creating ornaments out of clay, the thickness is an important consideration that impacts the final outcome. Generally, a thickness between 1/4″ and 1/2″ provides a good balance between strength, weight, drying time, and ability to capture fine details. Thinner pieces are more fragile while thicker pieces take longer to dry and fire evenly. The type of clay also factors in, as some clays like polymer clay can be baked thinner than clays like air-dry that require more bulk. Be sure to use tools and techniques suited to the clay thickness, like smoothers instead of fingers for thin areas. Troubleshoot issues like cracking or slumping by adjusting thickness. Overall, test different thicknesses with your clay type to find the ideal balance for your ornament designs.