When it comes to drying pottery, slow and even is always the best way to go. Which raises the important question, how long pottery should dry before firing? On average it should take 1 to 2 weeks for pottery to
dry completely, sometimes longer depending on conditions. Drying times will differ because of climate, the size of your piece, the thickness, and the drying technique you choose. If your pottery is not bone dry before firing, there is a higher chance of cracking or even breaking in the kiln. The more you know about the drying process, the less likely you will have cracks.
How Do You Know When Your Pottery Is Dry
When your pottery dries, the color of your clay turns lighter.
Since there is about 20% of water in clay your pottery will also feel lighter because much of the moisture is gone.
If the clay feels room temperature or even a bit cool against your cheek it’s dry. If your pottery is cold like it’s been in the refrigerator, give it more time.
Climate Is A Factor
If the climate you live in is humid, your pottery will still have moisture in it after a week. Giving it an extra week or even two should do it.
Desert dwellers do have an advantage. Average size pottery will be bone dry in a week sometimes even sooner. Arid climate also has a slight disadvantage also, the clay can dry too fast and crack. Tenting will help with that.
The Size Of Your Pottery Matters
When your pottery is a half-inch thick or more, three weeks should do it. If you live in a humid climate and want to air on the safe side go for four.
When crafting a larger or more complicated piece like a girl on a bird, it’s worth taking extra time to make sure your pottery is totally dry.
What’s In Your Clay
Not all clays are the same. Different clays play a big part in how long pottery should dry before firing. Clays with high plastics and finer particles have a higher water content like porcelain. Therefore they will take longer to dry, and shrinkage will be more significant.
The greater the shrinkage, the higher chance of your clay cracking.
Grog in clay will help reduce cracking, shrinkage, and dries faster.
Grog is ground up clay that has already been fired. Because the grog has already been fired it doesn’t absorb water, that’s why your pottery has the ability to dry faster.
There are different sizes of grog ranging from coarse to fine.
If you want to use clay with grog, know that your clay may be less flexible.
Grog works best when handbuilding large pieces like tall vases, the clay is stronger and has less shrinkage. Grog has tiny sharp bits in it and can be abrasive to your hands if you throw it on the wheel. Check out Choosing Your Pottery Clay – Best Pottery Clay For Beginners.
Depending on the clay type your clay can shrink anywhere from 2% to 10% during the drying process, which doesn’t include fire time. Your pottery will shrink even more in the kiln.
The clays with the highest shrinkage volume can crack if not dried evenly because the drying clay is pulling away from the moist clay and that’s when separation can occur. Stoneware has a higher shrinkage rate than earthware.
Here are a few ways to help with uneven drying.
Testing your clay is good for several reasons. You get a feel for your clay, and it’s workability. See how fast your clay dries and measure the shrinkage rate after bone dry. Also, measure the shrinkage rate after firing.
Drying in the sun:
When pottery is dried out in the sun, if it is a high shrinkage clay it should be watched carefully and frequently turned because all parts of the pottery are not in the sun at the same time, and the pottery is drying unevenly. The dry part will pull on the wet part and crack your pottery. Drying your pottery in the shade is better if you don’t want to risk cracking.
Drying Mugs with handles:
The reason why you have to be careful drying mugs with handles is that handles can separate from the mug. If the handle dries too fast it shrinks, and the handle pulls away from the mug.
Drying your mug covered lightly with plastic for the first day will slow the drying process down enough to keep the handle from separating and falling off the mug.
Flip your mug over after it is leather hard. This will also help your mug dry more evenly because the bottom is thicker.
Plywood lined with newspaper is good for drying large trays or plates. Particleboard is not as good because it tends to warp over time and drywall can dry the clay too fast.
This is an excellent way to slow the drying process down even more. Place plastic over your piece and allow the air to come in from the bottom at a slower rate. If the plastic is too heavy, it may put pressure on the clay. Keep the plastic off your pottery or use a very light bag, like a grocery bag.
Alternatives For Air-Drying
There are ways to speed up the process on how long pottery should dry before firing, but they are not without risk of cracking your clay. Slow is not the only way to go it’s just the safest way to go.
If you can’t wait for your piece to dry, there are a few things you can try.
Even when you want to speed things up a bit, drying still has to be slow, low, and even.
Here are a few good ways to do it.
Set your kiln to 180 degrees Fahrenheit (82 degrees Celsius) for 8 to 12 hours. Candling will take any moister out of your pottery evenly and much faster than air drying.
If you decide to use a heat gun to help dry your clay, use it with care, and make sure you dry the pottery as even as possible.
Set the gun temperature at 120 and keep the gun at least 5 inches away for no longer then 15 minutes if you want to be on the safe side.
Dryers are not recommended for drying because they blow the hot air too hard on the clay. If you want to try a blow dryer, it’s best to use it with care and on the lowest setting.
If you use a fan, don’t put it directly on the piece. Allow the air to circulate around the room instead. You don’t want a fan blowing on one side of the pottery. The shrinkage rate will be too one-sided. That’s a recipe for cracked clay.
If you do crack or break your clay before firing the good news is you can still reclaim the clay. See our related article: How Many Times You Can Reclaim Clay
Putting your pottery on a shelf for a week or two to dry is fine, just make sure it’s not under a fan or vent. After molding your clay into a piece of art, having it crack or break from drying or heating too fast can be disheartening. That’s why slow and low is the best way to go.
POTTERY CRAFTERS THOUGHTS… Yes, pottery takes time, but that’s fine. The sweet satisfaction of creating something unique from a chunk of clay is totally worth the wait.