Thursday, June 9, 2011

Rehydrating Clay

Some ideas on rehydrating and storing your clay...

With the end of the school year I've been busy cleaning and storing supplies. Before I pack the unused clay away I go through the steps below. When I come back in the fall it is ready to go!
This works great for clay that has dried out after using it in class. It's ready to go in a day of two.
All of my clay is stored in a clean lidded garbage barrel. I have three barrels per school. The barrels help keep the clay moist throughout the year when it's not being used.

Keep the barrel on coasters. With all that clay inside it will be really heavy and you'll want to be able to move it easily. This coaster was a spare my custodian gave me. Check with your custodian before making or purchasing one, sometimes they go through cleaning sprees and they toss some cool stuff.

Keep your clay in smaller plastic bags within the barrel. In this picture this is the bag the clay came in. I've worked in schools where I've found all the clay dumped straight into the bottom of the clay barrel. After a year the clay dries out a little... a year after that and it's leather hard and an impossible dense mess that you can't get out of the bottom of the barrel. Smaller plastic bags keep the clay moist and easy to get in and out of the barrel.
The craziest thing I ever saw in a clay barrel: someone had wet a towel and laid it over the clay before putting the lid back on and leaving for the summer. When I opened the barrel in the fall the wet towel was BLACK with mold. Gak! I was freaking that I had breathed it in when I opened the lid. I closed it up again and hauled it to the custodian and told him to toss the whole thing and NOT open the lid.

Okay, so to hydrate the clay you'll need bagged clay and a long paintbrush.

Use the handle of the paintbrush to poke multiple holes into the clay.

Make the holes deep in the clay.

Pour water into the holes. Fill to the top of each hole.

Close the bag up again and place it back in the barrel.

With all the clay wrapped up in bags I usually lay some plastic over the top of the bags and close the lid tight. In the fall the clay will have absorbed all the water and be ready for you to use.
Thank you Kathy H. for sharing this tip years ago at one of our elementary art department meetings!


  1. Kathleen,
    Great advice. Something I knew nothing about. Our school has a kiln, but I have not been able to use it for the last 16 years since it is in a room where books, etc. is stored. I have all but forgotten my clay skills.

  2. great advice. I was just thinking about what to do with the clay I didn't use this year. Thanks for the tips!

  3. Another method is to wrap the clay in a wet towel, completely covering clay and place clay back into the bag, sealing it and leaving it for a period of time. The clay will be soft all the way through. The time in the bag depends on the atmosphere.

  4. Felt works as a great hydrating drape for clay and since Wool has lanolin which makes it and felt made by wool a naturally anti-bacterial – mildew and mold doesn't grow on it!
    I make small medium and large sized clay meatballs and place in a large tupperware bin, cover it with wet felt and seal with a lid. When students need more clay they have various sizes to choose from and its all stored moisted and mold free. Hope this helps!

  5. I just saw this on Pinterest, thanks for the tip, I have a bag of clay that needs this restoration.

  6. I've done this before and it does work. The clay just has to be somewhat soft in order to get the brush in.

    1. Gabriela, I reclaimed ROCK HARD clay this year. Got a new plastic tupperware and placed whole bag inside. Poured about 20 oz of water over it. Came in next day and rotated the block 180 degrees inside the bag. Did this 4 more times (once per side of the "cube". After day 5 I could get a brush about half way in. Filled the holes. Three days later could get paintbrush all the way through. It was only 5 minutes per day. Not much compared to tossing the clay.

  7. I also use a wet towel on the clay, but it never got mold on it. Even after a couple of weeks.

  8. Apparently I put too much water in my clay, because after leaving it over spring break, I have 2 bags of VERY soft mushy clay--too soft for 1st graders to work with. Any suggestions on how to reverse the process a little bit?

  9. Oh oh... sorry to hear that! I'm guessing it messed up your lesson schedule, ouch! Evaportation goes pretty fast. Do you have a flat board you could lay your clay out on? (I use a flay 12x18 board originally meant to be an outside drawing board.) Cut the clay up into chunks and lay it out so more clay surface is exposed. I don't know how wet it is so I don't know about leaving it out all night; maybe re-bag it before you leave school at night and lay it out again in the morning until it stiffens up. Hope that helps!

  10. some of it could also be used as 'slip' to join pieces together, sarahmcwhorter - but you've probably also fixed this problem by now!

  11. This will probable freak some of you out because it goes against what we've been taught, but I put water in the plastic bag with the clay, seal it up and put it in the freezer. Yes, that's right, the freezer. When it's frozen solid, I take it out and let it thaw. Most of the time, I only have to do this one time to rehydrate the clay, but sometimes I may have to repeat the cycle one more time. Don't know why it works but it does, and have never had a problem with unfrozen clay not performing as it should.