A Low Tech System for Recycling Clay Scraps
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As clay artists, we’re so lucky that we can reduce the amount of waste we produce by reclaiming or recycling our unfired clay.
(I use the words “reclaim” and “recycle” interchangeably.)
When we make something that cracks, warps or doesn’t look how we wanted it to, we can reclaim our clay, bringing it back to its original state so we can start over. As long as the clay hasn’t been fired yet, it can be recycled.
In this article, I’m going to describe the low tech system I use for reclaiming my clay scraps in my home studio.
My home system is different than the system we use at the public studio where I work. The public studio has many different users, different clay bodies and a big expensive machine called a pug mill that mixes our clay for us. I’ll describe that system and how it’s different in a separate article.
At home, I use a system that requires no fancy equipment, just a bit of time and effort.
Plasticity vs “Short”
For a number of years, I was diligently going through the motions of reclaiming large buckets of clay scraps a couple times/year. But I kept making one major mistake that resulted in really crappy (for lack of a better word) recycled clay.
A better term for this crappy clay is “short”. Short is the word that’s used to describe clay that has low plasticity, where clay is prone to cracking when bending, stretching and shaping.
If you roll a coil of clay and then bend it, it should bend nicely and not crack. If it does, it’s considered short.
Same goes for cutting a thick slab from a block of clay. If you bend it and stretch it, it shouldn’t crack like this clay did. This clay is short.
Plasticity refers to a clay body’s ability to be formed into a shape, and to retain that shape. Clay is what’s called a “plastic” material.
I know, it can be confusing to refer to clay as “plastic” when your brain has an idea of what plastic means. We might hear the word “plastic” and immediately think bad thoughts of killing the environment. But in ceramics, plastic = good!
Plasticity is not to be confused with “elasticity.” Elasticity refers to a material’s ability to be stretched or deformed and then return to its original shape. Plasticity means it retains the new shape.
A clay body that has sufficient plasticity will not crack when it is bent or stretched.
Here’s a general description of how the plasticity of a clay body works:
Wet clay particles attract each other like magnets. Water allows the particles to move and slide and stay stuck together as we shape the clay.
The other thing that’s required for plasticity is what’s called “clay particle size distribution”.
The better the distribution is of small, medium and large clay particles, the more points of contact we have between all the particles, and the better our clay will stay stuck together.
Here are some graphics to help explain what I mean. Note that clay particles are flat and not round, but you get the idea.
When we only have one size of clay particle, there are a lot of gaps in between them and less overall points of contact bonding the clay body together.
If we bend or stretch a clay body containing only one particle size, because there are fewer bonds, a lot of them will break, causing cracking. This is what happens when clay is short.
When we have a mixture of particle sizes, the small and medium particles fill in all the gaps between the large particles and now we have more points of contact holding the clay body together.
Remember, wet clay particles attract each other like magnets so the more points of contact, the stronger the overall bond throughout that clay body will be.
When clay is short, it means there aren’t enough points of contact, holding the clay together. There are gaps that show up as cracks in the clay.
“What the heck does this have to do with clay recycling,” you ask? Well, understanding how plasticity and clay particle size distribution work will help you to make sure you’re not producing “short” reclaimed clay like I was.
My Big Reclaiming Mistake
I mentioned earlier that I kept making a major reclaiming mistake that resulted in short and unworkable clay. The mistake I kept making was discarding my throwing water.
DO NOT THROW AWAY THE CONTENTS OF YOUR THROWING BUCKET
Let me explain the reason I was throwing this away and then why you should keep it.
One time in my early days, before I understood how clay bodies and plasticity worked, I tried reclaiming just my throwing bucket. I poured the water off the top, spread the sludge onto a plaster slab, let it dry out a bit and then tried working with it.
The resulting clay was a cracking, crumbling mess for reasons that are now obvious to me. But because this process resulted in disaster, I decided that the clay in my throwing bucket was useless and problematic.
I stopped adding my throwing bucket to my reclaim bucket and just threw it into my discard bucket where I dumped old glaze tests and clay that fell onto the dirty floor, etc.
The issue (and the benefit) of the throwing sludge is that it contains the smallest clay particles. A lot of the tiniest particles are removed during the throwing process and end up in the throwing water.
Without saving the throwing water, my reclaim bucket was lacking those smallest clay particles that contribute to the overall plasticity of the clay. I was throwing all those small particles away and then complaining that my clay was crappy.
Now that I know better, I keep absolutely everything. My throwing bucket, the contents of my splash pans, any clay that comes off my thrown pots with a rib, they all go into my reclaim bucket.
I don’t worry about how much water ends up in there. When I need more space in the bucket and there’s a lot of clear water on the top of the clay, I’ll siphon it off.
Water is very good for clay recycling and I’ll explain why down below when I describe my whole reclaim process.
If your throwing bucket has settled so there’s a layer of clear water on top, you can pour that off. Just don’t remove any clay particles. If the water is cloudy, it’s because of light, floating clay particles. You want to keep the cloudy water but if it’s clear, it can be poured or siphoned off the top.
I hope you can learn from my mistakes and have the best recycled clay possible. To do so, just keep adding everything to your reclaim bucket and then follow my instructions below.
What to do with short clay?
If you have clay that you think is short and you’re having trouble working with it, I would try mixing the short clay with some fresh clay out of the bag. I’d start with half and half and if it’s still not better, mix some more fresh clay in.
Hopefully that will work well enough that you can use up that short clay and your recycled clay will be better going forward.
My Clay Recycling System
I throw a very persnickety translucent porcelain off-the-hump (which means I can’t compress the bottoms while throwing) so if my clay’s short or not well mixed or off in any way, it will definitely let me know.
It’s important to me that my recycled clay isn’t more persnickety than what I’m starting with.
The system I use is thorough and may take more time than other ways of doing it. To me, it’s worth the extra time and effort. Short clay is frustrating and consumes more of my energy.
My system is also portable which is great if you work in a small space.
There are many ways to reclaim your clay scraps and you can adapt and create a system that works best for you.
Tools and supplies:
Here are the tools and supplies that I use:
- A bucket for your reclaim
- A drill with a paint mixing attachment
- A glaze sieve and long-handled scrub brush
- A plaster slab
- A 38L blue Rubbermaid plastic tote
- Wooden blocks
- Plastic squeeze clamps
- An old bed sheet
1. Make a plaster slab
If you don’t already have one, make a plaster slab that you can use to dry out your clay recycling. I made this one out of pottery plaster that I bought from my ceramic supplier.
I mixed up the plaster with water and poured a 2” layer straight into the bottom of a big blue Rubbermaid tote. The plaster then hardens and because the tote is flexible and tapered, the slab pops right out.
You can use other containers or cottle boards and clamps to make a plaster slab. Whatever works for you. I use the same tote for pouring my plaster slab and my recycling process so they fit together perfectly.
I made a few of these plaster slabs that I use both in my damp boxes and for recycling clay.
If you’ve never made plaster before, search Google or YouTube and there are plenty of articles and videos that can show you how. It’s really easy, just add water, mix, pour and set.
2. What to put in your reclaim bucket
I use a large bucket for my reclaim, one that’s big enough to dump my splash pans into after throwing. A 10-gallon bucket works well for this.
If you use different clay bodies, be sure to have a labeled bucket for each one.
In the bucket, I dump my throwing water, handle pulling water, the contents of my splash pans, any clay that comes off my thrown pots with a rib, my trimmings, slab cutting scraps, etc. All clay scraps.
With the throwing and handle pulling water, I usually allow the clay to settle overnight and pour the clear water off the top before dumping in the reclaim bucket.
Any clay that has dried past the point of wedging, I let dry out completely and then I throw the bone dry clay into the reclaim bucket.
When bone dry clay comes into contact with water, it sucks it in like a sponge and then slakes down, turning to mush.
I avoid adding leatherhard pots or partially dried lumps of clay to my reclaim bucket. Since partially dry clay’s pores already contain water, it doesn’t absorb new water and won’t slake down like bone dry clay does. It remains firm and unmixable.
A mix of wet and dry trimmings are fine because they’re so thin and have a lot of surface area.
3. Mix your reclaim bucket
Earlier in this article, I mentioned the importance of water for the reclaim process. If you want the best, highest plasticity clay possible (arguably even better than fresh clay out of the bag) then make sure your reclaim bucket always has plenty of water in it.
You want to keep enough water in your reclaim bucket that there’s always a layer of water sitting on top of the clay. This water does a couple of things.
One reason is for when you have dry trimmings or scraps and dump them into the bucket, they hit the water and slake down instantly.
But the more important reason is that liquid clay can flow and move and be mixed really well. Mixing is so important because you want all of the particles to be evenly distributed and homogenized throughout your clay body.
Clay is made of different sized clay particles (as we know) plus silica particles and fluxing particles. If your clay isn’t mixed well, you can end up with pockets of flux and no clay, or pockets of large clay particles here and small clay particles there.
All of this can affect both the clay’s working properties and fired results. The better your clay is mixed, the better it will perform. This is not unlike the importance of mixing glazes really well, as described in this blog post.
You essentially want your clay reclaim to be a big bucket of liquid clay slip that you can mix with a drill and paint mixing attachment. The more fluid it is, the better it will be mixed.
And the reason why your reclaim could possibly be better than fresh clay out of the bag is that clay companies don’t tend to mix clay in a liquid state. It would take too much time to remove all the excess water.
They have big, fancy mixing machines and they do what’s called “plastic mixing” where they add just enough water to get the clay to working consistency and mix it in the plastic state. It’s basically like super wedging.
The clay companies do a better job of mixing with their equipment than we can do by wedging, but mixing a liquid will always be more effective than mixing a solid. By definition, liquids can flow and solids can’t.
And since most of us don’t have fancy mixing machines, the better the clay is mixed before we have to wedge it, the easier it will be for us. We have the ability to mix our reclaim really well in a liquid state.
When you’re ready to recycle your clay, the first step is to use your drill and paint mixer attachment to mix it in the bucket. Mix for a few minutes. The longer the better.
Don’t worry if your clay is slightly lumpy, we’ll get rid of those lumps in the next step. But make sure your clay is fluid enough to move and pour out of the bucket. If it’s not, add a bit more water and keep mixing.
4. Sieve your reclaim
Wait, what? Seriously?
Yes! I sieve my clay slip just like I would sieve a glaze. I do this for 2 reasons.
Reason #1:
Our fuzzy companions are full of love but they’re also full of FUZZ. And I just can’t handle it when I find black dog hair in my white porcelain.
Sieving my clay removes any hair or bugs or whatever else may have fallen in the bucket over time.
Reason #2:
It makes the clay so nice and smooth, which makes me happy.
You can only sieve your clay if it’s in a liquid state, otherwise it will take forever. Hopefully you added plenty of water during the mixing process.
I usually mix and sieve my clay one day, and then let it sit for at least a day. Once it’s settled, I siphon any excess water from the top before moving onto the next step.
There’s a balance between wet enough to mix well and so much water that it takes forever to dry. I like to add extra water for the mixing/sieving process and then remove as much as I can before the drying process.
5. Blocks in the tote
I take my big Rubbermaid tote that fits my plaster slab and put wooden blocks in the bottom.
The blocks are to raise the plaster up so there can be a bit of airflow underneath. This helps to speed up the drying process. If there’s a lot of water, the water can drip out of the plaster and we don’t want the plaster sitting in a puddle.
I like using a tote because it’s portable and I can move it around my studio if I need to. I can also put the lid on to slow down the drying process if I need to.
6. Plaster slab on the blocks
I put the plaster slab on top of the blocks.
7. Make a bedsheet bowl
I then take a piece of an old bedsheet and lay it on the plaster. I use plastic squeeze clamps to clamp the sheet to the sides of the tote. Make sure the sheet lays flat on top of the plaster.
This creates a nice big bowl that I can pour the smooth clay into. Since the clay is so fluid, I don’t have to worry about it leaking over the sides of the plaster. I can add a much thicker layer this way.
8. Pour the clay
Pour the liquid clay into the big fabric bowl.
9. Wrap clay in bedsheet. Flip until wedge-able.
I carefully remove one clamp at a time and fold the two long sides of the sheet over the clay, and then the ends, wrapping the wet clay up like a present.
Then I let it sit. It usually takes a few weeks to get to wedging consistency in my cold studio. Times will vary depending on your studio environment.
If you want to speed up drying you can put a fan on it. Just keep checking that it’s not drying out too much.
Once the bottom has firmed up a little (still quite soft), I flip the whole thing over and allow it to dry from the other side. I continue to flip it over every now and then. One side is drying from the air and the other side is drying from the plaster.
One thing the sheet is great for is it prevents the edges from drying faster than the middle. The sheet helps to keep the moisture content fairly even.
I’ll often roll the clay in the sheet with my hands, trying to mix the dryer outer layer with the softer clay in the middle.
If I have a dry plaster slab handy and I’m trying to speed things up, I’ll trade the wet slab for the dry. The bedsheet makes it really easy to do this.
You don’t have to have two plaster slabs but if you do it will speed up the process. Or you can do two batches at once. If you’re going to be pouring plaster, I recommend making the most of it and pouring two slabs.
I tend to the clay in these ways, making sure it dries evenly until it’s ready to be wedged. Then I bag it up and it’s ready to go. Nice, smooth, plastic clay, ready to be made into whatever I want.
A 9-step clay recycling system
Here’s a recap of my clay recycling system.
- Make a plaster slab
- What to put in your reclaim bucket
- Mix your reclaim bucket
- Sieve your reclaim
- Blocks in the tote
- Plaster slab on the blocks
- Make a bedsheet bowl
- Pour the clay
- Wrap clay in bedsheet. Flip until wedge-able.
I hope this either helps you improve your recycled clay or motivates you to tackle those reclaim buckets that you’ve been neglecting in your studio. We’ve all been there! Having a good system makes it easy.
Do you have any clay recycling tips to share? Post them in the comments below.
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I use the same method as you to recycle my clay but to save time I buy in DIY shop plaster tiles that I put on a chair from which I removed the fund so that the tile is well ventilated. Instead of sifting my underwear I use a soup mixer that I plunge into the bucket and that allows me to have no more lumps. To get rid of the air that the mixer has introduced into the slip, I mix 1 minute with a wooden spoon before pouring on the cloth on the plaster tile.
Thanks for sharing your techniques!
Thanks for sharing your process!
Thank you for posting this! I have been recycling everything clay for quite a while, including throwing water. I use a 2 gallon bucket and place it on the table next to my wheel. When I throw and my hands get full of glop, I wipe it into my reclaim bucket instead of my throwing water, so that it stays cleaner a while longer. Also, since I have had back problems, it is much easier for me to lift and pour the smaller size. I scoop it out onto my plaster wedging board and then let it dry for a couple of days, flipping it when it becomes solid enough on the bottom to come off in a sheet. Since I can’t wedge while that happens, I do hand building in the meantime.
My only problem has been with my current clay body, B Mix 5. I think some sort of soluble salt is absorbed into the plaster. When the plaster dries out, there is a strange white fluffy growth that looks like mold around the perimeter. When I touch it, it turns into a powder. I’m thinking it may be from a flux that dissolved into the water. The B Mix 5 seems to be a bit short after I reclaim it whereas none of the other clay bodies I’ve used have done this. Any ideas on what it is?
Yes, you are right. That white fuzzy stuff is salt precipitating out of the pores of the plaster. It happens to me too. I use Laguna Frost. Not sure why the BMix would produce worse reclaim than other clay bodies. Do you throw with BMix and handbuild with other bodies?
I throw and handbuild with B Mix. Actually, I think the issue is that it’s the first grogless clay I’ve used! It took me a little while to get used to throwing it and I guess that contributes to its shortness as well. I just use my reclaim slightly more damp than out of the bag and that solves the issue. I probably just need to wedge it better, but I am a bit lazy about that! Thanks!!
Hi there, I’m using a very similar process but haven’t been sieving and I definitely need to! Particularly for the pet hair! What kind of sieve are you using? Thanks for such a detailed description!
I use an 80 mesh glaze sieve as that is what I have around. A coarser sieve would work as well to remove hairs and debris, and would be faster.
I’ve tried an 80 mesh sieve but my that removes the fine particles from my slightly flecked clay so I’m going to get a coarser sieve. I think the 80 mesh will work fine on my white clays.
A very good point, I’ve never used speckled clay and mesh size is definitely something to consider.
Sue
Hi girl- you’re amazing and I’m so excited to see the results from this process (I’m waiting for the clay to dry I used way too much water lol). Question, though – when you flip the clay you just keep in the sheet and flip? The consistency of mine is still pretty wet so that’s the only way I would be able to do it
I keep it in the sheet until it’s firm enough to wedge. Sometimes I roll it around in the sheet to move the moisture from the middle outwards.
Great article. What is the mesh size of the sieve you use?
I use 80 mesh but 60 would be fine as well.
It was a very good read. I recently started my own studio and such a detailed explanation of the process was much needed. Thanks.
So glad to help. Good luck with your new studio!
When you see that your clay is short throw in some powdered china clay while it is very wet. I got this advice years ago from a person at Seattle clay. It has worked for me during the last 20 years and I recycle all clay.
This is a great system! I have always kept all clay and water in a big container next to my pugmill when I make new clay I use that instead of fresh water to mix the dry materials- this was how I learned to make clay at school and I’ve stuck with it ;). When I have not had a pugmill I’ve used a plaster bath but it is heavy, takes up a lot of space so it gets stored when not in use, then it is hard to move where I need it. Your system of the fitted plaster slab in the bottom of the tote is the perfect solution! Thank you for sharing this.
Yes, my pug mill recycling technique at work is much different than this. We add a recipe of dry clays to the wet clay scraps, which introduces all the particle sizes again. No plaster batt required.
I just can’t tell you how very very thankful I am for this post!! I have had a huge problem with dog hair in my clay and I was literally about to throw 3 gallons of slip out!! I did a lot of slip casting back in the day. I had a bunch of green ware I was never going to use so I loosely dusted it all off and threw it in a big bag which was inside of a box. I put it in a bucket and broke it up as small as I could, poured water over it and mixed it with my hand, let it sit a few days and then I used the jiffy mixer in it and I got a big fluffy surprise when I took the mixer out of the clay!! There was a lot of hair on it!! I thought not again! Yes I have even had hair in my handbuilding clay. Don’t know how but there was quite a bit. So I went online to see if anyone else had ever had this problem, I had searched before but found nothing, then I found this post!! Thank you so much for explaining what I can do now.
Hi Sue! I run a small community studio here in Australia (although I’m from Vancouver!) and I was wondering if you could share your process reclaiming at work? We have Peter Pugger and we have so much to reclaim, all different sorts of clay. I would Really appreciate any tips!
HI Sue I have been reclaiming my clay right from the beginning in my home studio. I just use a plaster batt and flip when it is ready. Wedge it a bit and put it back on the slab.
I was using a whisk to mix my reclaim to make it smoother then got the brilliant idea to use the drill and mixer last year when I was mixing glazes. To get the cat hair and larger lumbs out. I have always used my slip water so that is a good thing. I got my Husband to make a screen with a wood frame so it sits above the plaster batt and sieves the clay when I put it on. It goes through the screen on to my batt. It works really well. I was fortunate enough to find a used table top shimpo pugmill in good shape and at a good price. It is a dream. Again my handy Hubby made a portable table with wheels for it and I can move it around to where I need it. I wish I had your information early on, thank you for the article. It has taken me 8 years to get to this point with my reclaim. I see I am doing it right finally.
Handy hubbys and pug mills are the best! Glad to hear you have a good recycling system.
I live in the country and rely on tank water so I reuse every skerrick of water I can, including having a bucket in my sink to catch the clay from my hands when I wash them. All of my throwing water goes into the reclaim bucket and also any glaze materials from cleaning up brushes and stirring sticks. It makes sense to reuse whatever you can. I don’t mind the dog hair so I gave up sieving because it was too time consuming. Thanks for the explanation about the particle sizes.
Yep, keep everything! Except the dog hair 😉
Can I put my glazing clean up water in my recycle clay bucket?
I would keep the glaze water out of your clay. Adding glaze particles to your clay could potentially lower the maturing temp of your clay, which could lead to bloating.
Sue
Hi,
I also reclaim my fines from the throwing bucket but I use as much as I can of the water too as the salts that came out the clay are dissolved there and contribute to the stabilization of these fine particules in the water. Otherwise they’ll coagulate preferentially together before mixing with the bigger clay platelets.
Hi and thanks for the advice. Can different clays that are the same cone temp. be mixed together ?
Can of types of plaster be used other than casting plaster ?
Thanks again !
Yes, different clays of the same temp can be mixed together. I don’t know much about different types of plaster. The plaster I use came in a 50lb bag from my ceramics supplier. The purpose of the plaster is to absorb moisture so if other types of plaster are also absorbent then I don’t see why they couldn’t be used as well.
Sue
thanks Sue! Is there any way to reclaim the clay in my cleaning bucket?
Hi Bill,
Not sure what you mean by cleaning bucket? I put all clay together in one bucket and reclaim everything.
Sue
I use bisqued bowls, about 12″ diameter, lined with thin landscape cloth which won’t rot. I have about a dozen bowls, so I can reclaim a little or a lot at a time. Depending on how thick the clay slop is, it may take a week to firm up. Once the reclaim can hold its shape when lifted from the bowl, I place the reclaim, still in the cloth, on top of newspaper to dry further. The bowls also can handle very wet slop, and I have even decanted water from the top later. The bisqued bowls need a top border (about 1″) of low-fire glaze to prevent spalling (flaking) of the bisqued clay at the upper lip over time due to migration of salts.
Thanks for sharing your process!
Sue
Thank you so much for this! Quick question – how long do I leave the clay slaking in the bucket before I attempt to mix with the paint mixer?
Thanks,
Jay
If I’m starting with dry clay and just adding water, I generally leave it for a day or more. It depends on the size of the clay pieces that you’re slaking down. Thin trimmings will slake down fairly instantaneously. Thicker clay takes longer. Like if we’re recycling a bunch of bone dry, abandoned pots of various sizes at the studio where I work, I’ll add them to water and wait a day before mixing.
Sue
Hi, the other variable is how long you leave the reclaimed clay to age in the bag before using it. I favour at least 4 months.
Called “souring”, I have been told this allows a colony of microorganisms to grow which aid the clay particals slipping past each other. I tend to let a lot of my clay dry out completely as it’s easier to store that way. Then I use hot water to reconstitute, so maybe it makes more of a difference after that than your way when most of the reclaim is never dry
My clay generally sits in a bucket for at least 4 months before I get around to recycling it so I’m sure it’s good and sour by the time I get around to actually using it 😉
Hi Sue! Speaking of sour…since reading your post, I’ve started keeping my throwing water and scraps, etc., in a big bucket. It’s probably been 6-8 weeks now. I noticed that my trimming scraps hadn’t gone to the bottom of the bucket yesterday and when I reached in to poke them down I encountered a kind of gelatinous . . . being? . . .let’s call it . . . layer . . . in there. It breaks up if you smoosh your fingers through it. Is this some kind of microorganism/ mold/ swamp creature (something like the SCOBY in a jar of kombucha?), and is this normal? What do you think: should I blend away or throw it out?
Hi Louise,
Interesting… I can’t imagine that it could be anything bad. Does it seem like clay when you squish it up? Was there a layer of water on top? I’m wondering if the top layer dried out a bit and thickened up. Can you post a photo or video of it to my Facebook group Understanding Glazes with Sue?
Hi Sue,
Thanks for answering! There’s definitely a layer of water on top, though it’s cloudy like water after throwing rather than clear. What does it squoosh like? Not clay. More like a light flan or custard or set yogurt before it’s been stirred up. I’ll try to scoop some out for a look. And by try I mean screw up my courage. It does rather feel like poking the swamp monster. 🙂
So it looks like there’s no actual swamp monster. The squoogy texture is (I think) trimmings.
Do you ever just let clay dry out a bit and rewedge it? or does it all go into the reclaim bucket?
I do dry out and reuse clay off the wheel. But you just have to be careful because if you reuse it too many times it will become short.
I use a speckled brown clay with grog (Highwater Speckled Brownstone). I own a 60 mesh sieve – do you happen to know if this type of grogged slip can be sieved successfully? Thanks for the great blog post.
Very good question. I haven’t used grogged clay before so haven’t run into this. I doubt a 60 mesh sieve would let the grog through. You may have to skip the sieving step, or sieve out the grog and then add it back in. Or add in fresh grog?
Thanks for this information Sue. I’ve been putting this job off for ages! I have been saving the dry clay but have mixed different bodies together. Beginners mistake. I’ve been thinking that it could still work but it will just be an earthenware suitable body. Would that be right or would I just test fire to see if it’s viable at all? Just seems a waste to throw it all out.
Mixing different bodies together is ok if they’re meant for the same temperature. I would definitely still do a test fire but as long as you’re not mixing high temp clay with low temp clay, you should be fine.
Sue
Great post Sue. I use a similar process but have a plaster trough cast from a mold and I use pillow cases for the bowl and rotate towels under that to help wick moisture. I’ll have to consider sieving the slip.
Great article Sue I’m glad you shared video as I’m learning your great hints all the way over in Sydney Australia so when you wrote Tote ,, I was perplexed ??Thanks so much Keep up the videos Their so encouraging ??
That’s funny! Would you call it a bin? A plastic storage container?
Great advice! How much plaster did you need for one of the tupperware bins? I want to make one and don’t know how much plaster to buy. thank you so much!
I honestly can’t remember exactly, it was a long time ago. But I know that I started with 50 lbs of plaster, I made 4 of these and I still have a bunch of plaster left. There are ways to calculate how much plaster you’ll need to fill a certain size, you should be able to find some instructions if you Google “plaster calculator”.
Thank you so much for all this great information. Setting up a home throwing space and need lots of advice. How much plaster was needed for the storage bin plaster? I want to make one and don’t know how much plaster to buy. thank you!
Thank you so much for writing this! How do you siphon off the clear water on top of the bucket? I thought about a turkey Baxter but that seems like it would take forever!
Turkey baster*
I mix my recycled with fresh clay 50/50 but sometimes it is a bit short
I’m curius about the recipe you add to recycled clay at work. You mentioned BC, kaolin and one more…
Could you please share it?
We add 2 scoops Ball clay, 1 scoop Fire clay, 1/2 scoop EPK to the clay mixer/pugger at work. This produces a buff stoneware clay.
I use a large sponge to soak up the water off the top. A turkey baster would work too!
This is an excellent blog and such a great system! I’ve been doing my best reclaiming and was looking for a solution for removing the evidence of my own fur-babies’ attentiveness when I’m in the studio. I will try your solution!
Additional Question: a couple of times I’ve had issues when trying to keep my throwing water/clay, in that a black-something-super-nasty grows in it — skipping right over ‘sour’ clay to ‘sewage’ [smelling] clay. The only answers I’ve gotten when I’ve asked others is ‘mold helps with the plasticity’, which is great and all, but I have a hard time believing they’re referring this foul outcome. Any thoughts on how I might avoid it? Or could it be that this what people are referring to as something good?
It’s common for recycled clay to have an odour and turn black from mildew. The black colour will burn out during the firing. Sometimes I’ll add a drop of bleach to the bucket and mix it into the clay recycling before sieving and drying out. This helps with the odour and kills the mildew.
Great website Sue!
Some potters recommend adding reclaim fix, eight parts ball clay (Om4 or FHC), one part silica, and one part feldspar, up to a cup (dry) per gallon of slurry. I add a quarter cup or less per reclaim batch – about two gallons.
Hi Tom, I haven’t heard of this formula before but seems like it would help to add back some of the particles that were removed during the making process.
Great post. I have completed my first batch, it was quite smelly when mixed, and turned a black/grey from inside out. It wedged up well though. Can I presume that this “now quite grey” clay is not harmful to use? It still has a slight odour, but not as bad as it was when it was sitting. It did sit for about 3-4 weeks as I continued to add my scraps and throwing water.
It’s common for recycled clay to have an odour and turn black from mildew. The black/grey colour will burn out during the firing. Sometimes I’ll add a drop of bleach to the bucket and mix it into the clay recycling before sieving and drying out. This helps with the odour and kills the mildew.
Hi Sue,
When making your plaster slabs in the blue Rubbermaid bins, how much plaster did you use for each one? I’m not sure how much plaster to order. Would 5kg be enough for one or two slabs?
I’m really looking forward to your Mastering Glazes course!!!
Honestly, it’s been so long since I made these that I can’t remember how much plaster I used. Here’s a link to a handy plaster calculator that you can input dimensions and it will tell you how much plaster to use. https://plaster.glazy.org/
Thanks for this information! I wish I would have seen it before I reclaimed my slip the first time because I love the tip about using a bed sheet! I put the slip right on the plaster and when I scraped it off I noticed streaks of plaster in my clay. It wasn’t chunks or pieces in my clay but just streaks of plaster (like chalk on a chalkboard). Will that cause popping? Should I trash my beloved clay and start over? I’ll use the bed sheet next time! Thanks in advance for your reply!
And how do people manage slop bucket stink?? I think it is from sloughed off skin in the throwing water that rots and stinks, and other bacteria, etc. I’ve heard some people add vinegar, but this is not a great idea I think because vinegar suspends particle. I read one suggestion of adding some copper carbonate, and that seemed to help with no adverse impact on clay body (talking like 1/4 cup to 5 gallons of semi dried (much of water mixed in) slip. Other suggestions?
I will mix in a small splash of bleach if my clay bucket is particularly stinky. This usually solves it.
https://www.thestudiomanager.com/posts/the-best-way-to-eliminate-odor-from-a-stinky-ceramic-slop-or-glaze-bucket
Here is the link i reference
Hi Sue! How did you learn about the different clay particle sizes and the clay being “short”? This is amazing! I learned so much today!
Hi Catherine,
I took a clay bodies class online through Alfred University several years ago where I learned a lot about what makes clay plastic vs short. So glad to hear you’re learning helpful information!
Sue
I tried using my throwing water from the splash pan instead of fresh water from my bucket –it made a noticeable difference while throwing. There was noticeably more plasticity and smoothness while pulling than if I used fresh water. I’ll continue to rewet my sponge with my splash pan water from now on.
I had been skeptical any time I heard about clay “particles” –this blog post convinced me it’s not some wives tale. It also explained why some clay I was given, although moist and plastic, was short and very ornery to work with. I’ll always save and work with muddy water from now on.