If you are a potter, ceramicist, or glass fuser, you have likely heard of kiln washing. But what exactly is it and should you be doing it to the bottom of your kiln? Let’s look deeper into what kiln washing is, the benefits of it, and the supplies and steps you’ll need to take to do it properly.
What is Kiln Washing?
Kiln washing, also known as “kiln coat” or “biscuit fire”, is a way of protecting the inside of your kiln by applying a thick layer of specially-formulated wash onto the bottom of it. The kiln wash helps to prevent glaze runs and other glaze imperfections when firing your pieces. It also helps create an even temperature and helps keep the inside of the kiln clean by absorbing spills and debris.
Kiln washing is an important step in the firing process and should be done before each firing. It is important to use the correct type of kiln wash for your kiln and to apply it evenly and in a thin layer. It is also important to allow the kiln wash to dry completely before firing, as this will help ensure that it is properly adhered to the kiln walls.
The Benefits of Kiln Washing
Kiln washing helps to produce better glaze results, which means fewer rejects and more consistent firings from piece to piece. It also helps to prevent contamination of your glazes from stray bits of clay, dust, and other debris that may be on the kiln floor. Lastly, it helps protect the kiln floor from the intense heat of long firings.
Kiln washing is also beneficial for the longevity of your kiln. By removing any build-up of debris on the kiln floor, you can help to prevent any damage to the kiln floor that could be caused by long firings. Additionally, kiln washing can help to reduce the amount of time it takes to fire a kiln, as the kiln floor will be free of any debris that could slow down the firing process.
Supplies Needed for Kiln Washing
To successfully kiln wash your kiln, you’ll need some basic supplies. To start, you’ll need a kiln wash such as Raw Materials WT-10 Kiln Wash or any other special kiln wash approved by the manufacturer of your kiln. You’ll also need some tools such as a wide paintbrush and a small whisk broom.
In addition to these supplies, you may also need a few other items such as a pair of safety glasses, a dust mask, and a pair of gloves. It is important to wear these items to protect yourself from any dust or debris that may be released during the kiln washing process.
Preparing the Kiln for Washing
Before beginning, ensure that the kiln is clean and in good working order. This means that any debris, dust, or build-up should be removed from the inside surface, as well as from the burners, seals, and other parts of the kiln. The best way to clean the kiln is to use a soft cloth dampened with water and a mild detergent.
Applying the Kiln Wash
The next step is to apply the kiln wash. Start by stirring or shaking the wash before pouring it into a large container. A disposable tray or container works best for this because you can easily discard it once you’re done. Use a wide paintbrush to apply an even layer of the kiln wash onto the bottom of your kiln. Be sure to completely cover any joints or seams in the kiln surface with the wash.
Curing the Kiln Wash
Once all areas are evenly covered, it’s time to cure the wash. Place your kiln in a cool place – around 75-80°F — for 24-48 hours. During this time, don’t disturb the wash or subject it to extreme temperatures. This will ensure that the wash is properly cured.
Cleaning Up After Kiln Washing
Once the curing process is complete, you’ll need to clean up any excess wash with a damp cloth and small whisk broom to make sure all areas are free of debris or dust. Don’t forget to wear appropriate protective gear such as goggles or a face mask when cleaning up.
Common Problems with Kiln Washing
Sometimes it can be difficult to make sure that the wash is applied evenly and without any streaks or runs. If this happens, it’s best to wait until the wash has cured before trying to fix any unevenness. If you still can’t fix it after cure time, you may need to use a razor blade to scrape off any stains or unevenness.
Tips for Successful Kiln Washing
Finally, there are some tips to follow for successful kiln washing. When applying the wash, use a wide brush in slow, even strokes so that you don’t miss any areas. Wear protective eyewear and a face mask while applying and cleaning up after the wash. And make sure to allow enough time for curing – 24-48 hours – before firing your kiln.
Kiln washing may seem like a daunting task at first, but following these steps will help you achieve consistent, successful results and better protect your kiln. So if you’re looking to fire your most beautiful pieces yet, make sure to give kiln washing a try.
