Glazing and Firing Cement Pottery: A Comprehensive Guide
Cement pottery presents a unique challenge when it comes to glazing and firing. This article explores the complexities of these processes and offers guidance on how to successfully glaze and fire cement pottery without damaging it.
Introduction to Cement Pottery
Cement is a popular material for pottery projects due to its durability and strength. However, it is not typically designed to withstand the high temperatures of traditional kiln firing, which can lead to cracking, breaking, or the release of harmful gases.
The Challenges of Kiln Firing Cement Pottery
Firing cement pottery in a kiln is generally not advisable due to its inherent material properties. The typical temperature range for kiln firing is between 1800°F to 2400°F (1000°C to 1300°C). This high heat can cause cement to crack or break and may release harmful gases, making it an unsafe proposition.
Glazing Options for Cement Pottery
There are alternatives to traditional kiln firing for cement pottery. Low-temperature glazes specifically formulated for cement or concrete are often the best choice. These glazes can be applied without firing or may only require minimal heat for curing. Always follow the manufacturer's instructions for the best results.
Techniques for Success
For those who wish to fire their cement pottery, there are alternative methods that can be used. One such technique involves driving off the moisture from the cement before applying glaze. This can be achieved by heating the pottery at 450°F for four hours to drive off the moisture, allowing it to sit undisturbed for another 45 minutes.
Alternative Heat-Treating Processes
Some artists and craftsmen have experimented with custom heat-treating processes to achieve desired effects. For instance, heating the pottery to 1700°F can help drive off moisture and prepare the piece for glazing.
The Raku Technique
For an unconventional approach, consider the raku technique. This method involves adding various chemicals and metals to the cement mix, creating a unique and durable finish. One creative example involves incorporating elements such as horse poop ground into the mix. While such methods require extensive experimentation, they can lead to successful outcomes.
Other Glazing Methods
For a more practical and durable finish, flame spraying or plasma spraying glazes can be used on cement blocks. While this method produces an attractive finish, it is not as durable as other techniques. For those looking for very smooth concrete finishes, polymers are a better choice.
Conclusion
In conclusion, while traditional kiln firing is not suitable for cement pottery due to the risk of damage, there are alternative methods to achieve a beautiful finish. Whether through low-temperature glazes, custom heat-treating processes, or unconventional techniques like raku, cement pottery can be successfully transformed into a remarkable piece of art.