What Clay Can Be Used Outside?

Outdoor sculpture and art projects often call for durable clays that can withstand the elements. Certain types of clay are better suited for outdoor use than others based on their composition and firing process. When choosing a clay for outdoor use, it’s important to consider weather resistance, durability, maintenance requirements, and aesthetics. The optimal outdoor clay holds up to sun, rain, snow, and temperature fluctuations while retaining its color and form.

Clay that has been fired at high temperatures, such as stoneware and porcelain, tends to be most resilient outdoors. Alternatively, air-dry and polymer clays provide accessible options for simple outdoor projects. With proper sealing and care, many clays can survive outside for years, while unfired and porous clays may deteriorate quickly. Selecting the right type of clay and using protective coatings allows artists to create lasting outdoor artwork from clay.

Air-Dry Clay

Air-dry clay is one of the most convenient clays to work with for outdoor projects. As the name suggests, it dries and hardens at room temperature without any additional heat or firing required. This makes it very user-friendly for both beginner and experienced artists.

After shaping air-dry clay, simply allow it to dry fully over 24-48 hours. Humidity and thickness of the pieces affect total drying time. Once hardened, it can be painted, sealed, and displayed outdoors safely. The open air will not damage pieces made from air-dry clay.

Its ability to harden without firing makes air-dry clay suitable for all ages. The clay remains workable until it dries, allowing time for remodeling as needed. Cleanup only requires soap and water, with no chemical odors. When working outdoors, simply let any excess clay dry and brush it away.

While convenient, air-dry clay is not as durable as clays that require firing. It can become brittle and deteriorate over time when exposed to moisture and freezing temperatures. Proper sealing and protective finishes help maximize the lifespan of air-dry clay creations. Overall, it provides an accessible, weather-resistant clay option for outdoor projects.

Polymer Clay

Polymer clay is one of the most popular choices for outdoor clay sculptures and decorations. Polymer clay cures at much lower temperatures compared to other clays, usually around 110-265°F. This means polymer clay does not require firing in a kiln to harden and can simply be baked in a regular oven. The clay polymers cross-link and cure with heat exposure, allowing the clay to harden while retaining its shape and details.

A major advantage of polymer clay is that it does not require any special equipment or access to a kiln. Hobbyists and artists can work with it at home easily by baking pieces in their kitchen oven. Polymer clay also comes in a wide variety of bright, vibrant colors that remain fade-resistant when used outdoors. The smooth, pliable texture makes it easy to sculpt intricate designs. When cured, polymer clay is durable and waterproof. Sculptures made from polymer clay can withstand outdoor display year-round in any climate when properly sealed and cared for.

Oven-Bake Clay

Oven-bake clay, also called polymer clay, is a very popular type of crafting clay that must be cured in a regular home oven before it becomes durable. The baking process causes a chemical reaction that hardens the clay into a strong, permanent material. Oven-bake clay is made from substances like polyvinyl chloride (PVC) and plasticizers. It typically doesn’t contain any clay minerals at all despite its name.

The main advantage of oven-bake clay is that it can be hardened at relatively low temperatures compared to other clays. Most brands recommend baking at 265-275°F for 15-30 minutes. This makes oven-bake clay very easy and convenient to work with at home without needing a pottery kiln. Once cured, oven-bake clay is extremely tough and durable for outdoor use.

Oven-bake clay also comes in a wide variety of colors that maintain their vibrancy even after baking. It’s easy to mix colors and achieve custom shades. The clay remains flexible and workable until cured in the oven, allowing time for sculpting fine details and textures. These properties make oven-bake clay a versatile material for creating lasting decorative items and sculptures for the outdoors.

Earthenware Clay

Earthenware clay is porous when fired due to its low firing temperature. Because of this, any earthenware clay sculpture that will be displayed outdoors needs to be glazed so it can hold up against the elements. The glaze gives an impermeable surface so the clay underneath does not get saturated with water.

Without the glaze, earthenware clay is very permeable, and any moisture it absorbs can cause cracking and damage when exposed to freezing temperatures outdoors. The glaze acts as a protective barrier.

Typically, earthenware clay is fired at lower temperatures, between 1,800-2,200°F. This makes it more porous and prone to absorbing water compared to stoneware or porcelain clays that are fired at higher temperatures.

Earthenware clays are readily available and easy to work with. Just be sure to apply an all-over glaze if the finished piece will live outside. The glaze seals and protects the clay body from the elements.

Stoneware Clay

Stoneware clay is less porous than earthenware clay, making it more suitable for outdoor use. It vitrifies (becomes glass-like) at temperatures between 1185-1315°C. The higher vitrification temperature makes stoneware denser and more water resistant. Stoneware can usually withstand freezing temperatures, though thicker pieces are recommended.

Stoneware clays come in various colors like grey, brown, and red. The clay can be decorated using colored glazes and underglazes. When fired, the colors become more vibrant and glossy. The relatively low firing temperature allows for a wide range of decorative color options not always available for higher-fire clays.

Stoneware is an excellent choice for planters, yard art, and outdoor pottery pieces. It provides better durability than earthenware while allowing more creative freedom with colors and finishes.

Porcelain Clay

Porcelain clay is commonly used for making pottery, sculptures, and other decorative or utilitarian items that will be used outdoors. It is prized for its durability, versatility, and beautiful white color when fired. Porcelain clay has the following key properties that make it ideal for outdoor use:

• Non-porous – Porcelain clay becomes vitrified and non-porous when fired at very high temperatures (over 1200°C). This makes it impermeable to water and resistant to damage from freezing and thawing.
• Very hard when fired – Fully vitrified porcelain has an extremely compact molecular structure that makes it very hard and durable, similar to glass or stone. This prevents chipping, cracking, or breaking.
• Withstands weathering – The impervious, glassy nature of fired porcelain allows it to withstand exposure to sun, rain, snow, and temperature fluctuations outdoors without deteriorating.

The non-porous quality and hardness of porcelain makes it a great choice for planters, sculpture, fountains, tiles, and other decorative or functional items meant for outdoor use. Its resistance to weathering and durability allows porcelain pieces to last for many years outdoors.

Weather Resistance

Some clays are more resistant to weathering and the elements than others. When choosing a clay for outdoor use, it’s important to consider how it will hold up over time.

There are a few ways to test a clay’s durability:

• Leave clay outdoor samples exposed to sun, rain, snow, and temperature fluctuations for several weeks or months. Examine regularly for cracking, fading, and deterioration.
• Submerge small samples in water for extended periods to see if they become soggy or dissolve.
• Freeze and thaw samples repeatedly to simulate expansion and contraction.

Applying a sealer can help protect outdoor clay pieces. Sealers like varnish, polyurethane, and epoxy resin create a protective barrier against moisture and UV rays. Reapply sealers periodically as needed.

Stoneware, porcelain, and high-fire clays tend to be most durable outdoors. Low-fire earthenware clays are more susceptible to weathering and water damage over time. With proper sealing and care, many clays can withstand seasonal outdoor display.

Maintenance

To keep your outdoor clay pieces looking their best, some regular maintenance is required.

For cleaning, use a soft brush and mild soap and water to gently scrub away any dirt or grime. Avoid using anything abrasive or acidic that could damage the clay. A power washer can be used if needed, but keep the pressure light.

Check regularly for any cracks that may develop. These can be repaired by mixing a bit of water with clay dust scraped from the piece to create a paste. Press the paste into the cracks and smooth with your fingers. Allow to fully dry before sealing.

It’s important to re-seal outdoor clay pieces every year or two. This will protect the clay from damage caused by water getting into the material and freezing in winter. Use an appropriate outdoor sealer for the type of clay. Apply 2-3 thin coats as directed by the sealer manufacturer, allowing each coat to fully dry before the next application.

Conclusion

When selecting clay for outdoor use, the main factors to consider are durability, texture, color, and intended purpose. The clays that tend to hold up best outdoors are stoneware, porcelain, and polymer clay. Stoneware has a coarse texture that hides flaws well, while porcelain is smooth and refined. Polymer clay is flexible and lightweight. For color variety, polymer clays offer the widest range. If you plan to make garden sculptures or decorative objects, stoneware and porcelain are good choices. For jewelry or small accessories, polymer clay is ideal since it’s durable yet easy to work with. With proper sealing and maintenance, many types of clay can be suitable for outdoor display. Focus on selecting a clay that fits your project’s needs and aesthetic goals.