Reviving pottery clay is part and parcel of every potter’s journey.
Pottery clay can be revived since it doesn’t necessarily “expire” as we think of rotten mangoes or curdled milk.
While there are a few methods out there, factors such as how hardened your clay is and how patient you are will determine how you revive clay for reuse.
Here’s How to Revive Pottery Clay
You can revive pottery clay by chiseling the clay clump and soaking it in a bucket of water with the lid closed. The clay should be saturated and soft after a few days. Put the soft clay in a plaster slab to dry so that it sticks to itself when you work it more than it sticks to you, then bag it up.
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Can Pottery Clay go Bad or Expire?
Pottery clay can become contaminated by stuff that makes it unsuitable for making pottery, like sand, tiny amounts of iron, or cobalt.
If the clay is slip, it can get smelly, and if it’s been kept moist and sitting around for too long, it will sometimes get algae/fungus in it. Clay can also become unusable (go bad) when it dries out.
When pottery clay freezes, it’s both good and bad. The freeze-thaw cycle makes the clay more plastic, which is an upside. However, the downside of frozen clay is that it often requires more effort to get the air bubbles and cracks out of it.
What should you do If your Pottery Clay Goes Bad?
If you find your clay containing tiny debris like sand or iron, repeated mixing and decanting will get the contaminants out. Decanting also works for organic contaminants.
When clay is smelly, though, that’s a good thing. You’ll notice it has better plasticity, and it simply means that the organic matter in the clay is a host to bacteria living.
But not all potters like smelly stinking clay, and to get rid of the smell, use drops of bleach then thoroughly mix it. If pottery clay freezes, it has to be kneaded thoroughly, which requires a lot of effort.
Can Clay Mold?
When clay is damp and left hanging around for a fair amount of time, it’s not uncommon to see some white stuff sprouting on it. It’s mold. You’ll also notice a tad bit of suffocating air around moldy clay.
Some potters think moldy clay is good clay because it has better plasticity and therefore easier to throw with. Other potters prefer their clay pure without any mold. Some potters can indeed develop mold reactions and allergies to mold in clay.
What should you do If Your Clay Molds?
If you’re prone to allergic reactions and have mold on your clay, then you’ll need to get rid of the mold on your clay. The sure way of getting rid of mold in clay includes mixing it with Epsom salts, Dettol, vinegar, hydrogen peroxide, or bleach to eliminate the mold in clay.
Finished pottery pieces like pots and jars can also contain mold growing outside, especially when the surface stays wet. When this happens, you can scrub off the mold with a scrubby pad. Scrubbing may be unsightly, but it doesn’t hurt anything.
What Causes your Pottery Clay to Dry Up and Harden?
Clays are malleable or flexible when they have moisture in them and harden when they dry out. When soft clay isn’t worked for a long time, it will dry on its own as it loses its moisture.
You’ll need to figure out if your clay has hardened. After all, it’s settled or hardened because it’s dry. However, some clay bodies such as porcelain can tense up when settled without necessarily being dry.
How do you Soften Hard Pottery Clay?
For tense and settled porcelain clay, simply bagging it and throwing it on a hard surface will make it workable and smooth again. However, if pottery clay dries out and you can’t access a pug mill, then you have a lot of work to do.
You’ll have to break it up than dry it completely before slaking it in water to rehydrate it. But, it’s the easier way compared to trying to work water into hard pottery clay in its semi-dry state.
Stack and slam wedging is also a great way to soften hard clay.
Here’s how it works; take some slices of clay and sandwich some slip between them. Add slip on a few rounds of the stack, then continue to do at least ten more rounds, and you’ll have very soft clay to center and cone effectively.
Can you Rehydrate Bone Dry Clay?
Sure you can, and potters do it all the time. But it takes a careful re-wetting process and all the patience for days or weeks of wetting the clay surface then allowing it to sink in.
Also, thick clay pieces will require more time to rehydrate than thinner ones simply because they need more time to soak in the water fully.
However, rehydrating bone dry-fired clay may not help much when repairing finished, but broken pottery like mugs or jar handles. If, for example, your favorite clay pot falls and a piece chips away, make a new one if time allows.
How do you Reuse Hardened Clay?
There are a few ways to reuse hardened clay. The go-to way for life-long potters is a damp box. Typically, damp boxes use sets of plaster that absorb plenty of water that helps keep the air in the boxes very humid.
Rehydrating clay pieces this way requires excruciating patience but will result in a softened reusable clay. Another way is the bag and bucket method which means you’ll quickly dunk the clay piece then let it soak.
Feel the clay surface to ensure it’s not too wet, then dunk again. You’ll need to wait for 5 minutes between dunks for water to saturate the clay and make it reusable again.
Should you Combine Reclaim Clay with Fresh Clay?
You certainly can.
When you combine reclaim clay with fresh clay, add some water to your recycle bucket, a layer of water will form over the mixture. The clay scraps will all then become thoroughly saturated and break down.
The resulting clay material will have hard and soft spots. You can then mix it up thoroughly to have uniformly soft clay that you can use to make pottery.
Can you Reuse Fired Clay?
Clay cannot be recycled once it’s been fired, with very few exceptions. There are movements in different parts of the world to reclaim old fired pottery made of clay-rich in rare minerals like kaolin and quartz. Unfortunately, such attempts haven’t always been successful.
However, you can always reuse fired pottery such as statues, dishes, and other items made of clay. Broken pottery, for example, makes decent mosaics.
You can also donate fired pottery to charity to serve other purposes for other people when you don’t need them anymore, making pottery an interesting and fulfilling pursuit.
What is the Best Clay for Beginners?
The three types of pottery clay are earthenware clay bodies, mid-fire or high-fire stoneware clay bodies, and porcelain. For beginners, the best clay is nice smooth stoneware that doesn’t hurt and has enough texture to play with for a long time.
Stoneware fired at higher temperatures than earthenware making it non-porous. Perhaps it’s the best feature that makes it suitable for beginners is its versatility, making it easy to use hand-building, throwing, and sculpting.
Some beginners often rush for porcelain. This is a huge mistake, in part because porcelain is the most expensive clay out there and is largely silicate clay resistant to high temperatures making it difficult to work with for beginners.
Porcelain is also very unforgiving when you make errors, which you will do a lot when starting in pottery.
How to Keep Pottery Clay Moist?
If you keep clay moist and molded, it can last forever. However, if you buy your pottery clay boxes from places like Standard, High Water, or Laguna, they’ll guarantee the clay for six months to a year.
The simplest way to keep pottery clay moist for long periods is to simply double bag it. If it’s too stiff, then add some water, then seal it tightly. Depending on how stiff your clay is, you may need to wedge it to distribute the moisture evenly.
The plastic helps immensely in keeping moisture in the clay. If you find some mold growth, wedge it occasionally into the clay. Mold enhances plasticity in clay. In Asian communities like Chinese and Japanese, it’s how clay is kept for next generations to use.