Jump to content

Clay Recycling Advice Sought

Recommended Posts


I am new to both pottery and this forum.

I have just started throwing and am teaching myself from home, which happens to be a not very large boat so  I am trying to secure a studio space. Whilst I wait for that to become established I have been saving my waste clay to recycle when I eventually get some studio space. I have kept greenware and trimmings separate and dry in a small bucket and any wet waste clay I have stored in water in another bucket with a lid. This is where my questions come in

1). yesterday I noticed that the wet waste clay has started to develop a small layer of algae (I stupidly kept it on the deck and the buckets lid is white), I guess that means I should now discard it. Or does it?

2). Is there a maximum amount of time that waste clay should be left to slake? Aside from the risk of algae (!!!) will it end up too gummy if it sits in water for what is now coming up for a couple of months. If so, is there another way to store it til I get my plaster slab, just in an old airtight clay bag for example.

many thanks for any help

Link to comment
Share on other sites

I just did this myself a few days ago - forgot and put some still moist clay to slake in a bucket.  What I SHOULD have done was let it dry out completely, THEN slake it.  Or in your case I would suggest cutting it into thinnish slabs, letting it dry, breaking it up a bit if necessary and then putting it in with your other dry clay (trimmings I guess)?

Dry clay scraps slake a lot faster and more thoroughly than wet.  I knew this but forgot anyway LOL!

I don't know about the algae, I'll let others comment on that.  Potters typically don't care much about moldy smelling clay but algae?  Not sure.

I'm not sure why you have 3 things going with "greenware" which I assume means pieces you've let dry but don't intend to fire; trimmings which I think must be the scrap clay when you trim a piece; and then slops which I think you are calling "waste".  IF that is the case it is fine to let all three mingle, as it were.  But in a dry state, and slake only when you are ready to reuse.  Then you slake it, put it to dewater on a 3" thick slab made of (NOT PLASTER OF PARIS BUT) #1 Potter's Plaster, hydrostone, or hydrocal - hydrostone is my favorite - or a sheet of 1/2" (really .42") hardiebacker.  NOT DUROCK OR ANY OTHER BRAND OF TILE BACKER BOARD.  It comes in 3x5 sheets, you would need to score and snap it to about 2x3 or whatever size you feel is appropriate for a dewatering "board".  You could try layering 2 pieces that size and see how it works - the draw back of hardie backer over plaster for this purpose is it is so much thinner than plaster, but that is also its advantage.  You can't schlep a 3" thick slab of plaster around very well, but you can just lean the hardiebacker up in a corner or behind something when not in use, or carry it off somewhere for storage. But because it is so much thinner you will need to lay the wet clay out on it in strips to dry.  Otherwise if you put down one mass of clay it won't dry in the middle as fast as the edges.

I've used it this way but I just had the one piece - when I set up my studio I'll try double or triple layers and see if that works better to dewater.  It works great as ware boards or drying boards.  I think if it were thicker it would work better (as it is it works way better than plaster of equal thickness) if it were thicker, but I don't know if it would get good enough contact between pieces to help when dewatering.  Two .42" thick pieces is not the same as one .84" thick piece, if you get my drift.

Consider renting a small storage space until you can get a studio.  Some of them have electrical outlets and some are even "climate controlled". Even if not suitable to work in (and I know people who have used them as studio space for a variety of activities) you could at least free up some room on the boat.  You would most likely have to schlep water there if you tried to work in there, guerilla style.

Edited by Pyewackette
Link to comment
Share on other sites

Hi Egg,

Good questions!

I don't have definitive answers, however:

1) Is algae a deal breaker, my guess there is no. Try removing as much as possible, if it's clumped up.
Maybe add some hydrogen peroxide, although if they are green, darkness would do them in.
Once reconstituted and well on the way back to useable clay, the various blooms fade away and their smells as well, that's been my experience*.
So starting the recycle process and find out? If the clay is workable, and doesn't smell...
The plaster slabs are my preferred method also, however, there are other methods, e.g. pillow case, trouser leg, where the ready for drying clay goes in, then hangs where it's ok to drip until ready to be wedged up (try "recycle clay with pillowcase" search string in your browser).

2) How long to keep slop around, I also use buckets and lids.
I've had wet slop for at least six months afore doing a recycle.
Clay that I'm not planning to recycle soon-ish, as in the next several months, I slide the slop bucket along the wall under the shelf, where not as likely to have stuff fall in it and let the slurry dry out completely, then I re-lid it. 
The dry stuff accumulates in rectangular totes - they may be dishpans - that fit on my shelving system, out of the main air currents, where most of the dust just stays in the bins, else in the bucket with the fully dried out cake of slurry.

*I'm removing the clear part once the slurry/slop has settled, and hence, the amount of slop produced per recycle batch easily fits in a five gallon bucket. From there, add the bone dry load, let it soak, then start blunging, only add water if necessary. I use a large grout mixer driven by a half inch drill motor. Not being in any hurry, I'll blunge it some a few times a day until it's all smooth, running the drill until it's warm, not hot.
I add Nerd's fixit, just a quarter cup or so to a three gallon batch.
Recycling/Reusing Clay for Practice - Studio Operations and Making Work - Ceramic Arts Daily Community


Edited by Hulk
Link to comment
Share on other sites

I live somewhere dry, so algae isn’t ever something I’ve had to deal with. But I’ve left reclaim in storage for years, when I was in between studio spaces. I just kept it in 5 gallon buckets with the lids on tight. Bags will work well as long as they don’t have holes and aren’t moving it around a bunch.

If you’re slurry mixing your reclaim, you don’t need to lay it on plaster to get it to dry. You can hang it in an old pillowcase, or you can lay out a thrift store sheet on a wire shelf and spread your reclaim slip on that. Your slurry shouldn’t be completely fluid if you’re doing it up like this. 

If space is a consideration, you don’t need to keep your dried pieces, trimmings and wet slop in separate buckets. You can combine them into one. While bone dry clay does slake faster than leather hard stuff, it’ll all get there given time.  

When you say you’ve got wet waste clay, I assume that’s the pots that got too mushy, plus your throwing slop. You need to add the fine particles from the throwing slop back into the rest of the clay, or you’ll find your reclaim is short.

Link to comment
Share on other sites

On another thread around here someone told how they reconstitute their clay and dry it on fabric placed on shelves.  I've been doing that and it works great.   I keep my throwing water and add the dried trimmings to it, (usually within a couple days), let it sit and then pour and siphon off the excess water as it separates upward.  I have a piece of an old sheet  laid on my metal shelf, which also has window screening on it,  and I drop blobs of clay onto it.  I find blobs of about 1/2 to 3/4 cup dry out more uniformly than one big sheet does.  I check them a couple times a day, flip them once,  and when they're ready bag, wedge and reuse them.   Sometimes I mix  scraps, (all my clays are ^4-6) and other times I do them separately.

A great big thank you  to whoever it was that presented this idea.   It's so much easier than what I was doing before.  

Link to comment
Share on other sites

22 hours ago, Callie Beller Diesel said:

I do mine on wire shelves, not metal shelves. The idea is lots of surface exposure for water to evaporate from. 

(And you’re welcome. Glad it helped!)

Ah,  tho I consider  my wire shelves  to be metal,   they actually are  wire and not solid shelves.  That's why they have screening on them, so small drying items  can't  slip thru the slots.  Thanks again for sharing your excellent system!  Yes, wire, not metal.

Link to comment
Share on other sites

I lay mine on a thrift store bedsheet on the racking. Got the idea from seeing some folks who were digging and processing their own clay. They built wooden frames with hardware mesh that they then laid fabric on. The frames were stackable, so they didn’t need to take up a lot of space. 

Link to comment
Share on other sites

@Callie Beller Diesel I'm going to have to try that with sheets of hardiebacker.  Also the idea of clumps instead of long strips which is what I did in the past with my slop to dry it out.  It sure looks like I'm going to be processing more clay from dry or reclaim than I thought.  Once I've got my kiln stuff underway I need to get the pugger ordered too.  Still waffling between the VPM-9SS and the VPM-20SS.

Link to comment
Share on other sites

  • 2 months later...
On 5/4/2022 at 2:54 PM, Pyewackette said:

@Callie Beller Diesel I'm going to have to try that with sheets of hardiebacker.  Also the idea of clumps instead of long strips which is what I did in the past with my slop to dry it out.  It sure looks like I'm going to be processing more clay from dry or reclaim than I thought.  Once I've got my kiln stuff underway I need to get the pugger ordered too.  Still waffling between the VPM-9SS and the VPM-20SS.

@PyewacketteHow did this work out for you? I have multiple dogs, and while they don't come into the studio the hair still travels and considerable amounts still get in the clay (all shedding breeds).  In order to get as much hair out I have to get the clay to a very wet state, almost the viscosity for slip casting, to pass it through a mesh screen.  I have one larger sheet the hardiebacker board ~2x4'.  I"m finding this process is painfully slow since I've gotten to the point where I need this reclaim to keep throwing.  I need to get electrical hooked up for the kiln, so it's all practice, unless I happen to get a piece I feel very happy with.  

I am thinking about using one sheet to line between the backer board and the clay, then adding a second sheet to the top be able to put a new board on and flip the slab over.  Removing the original board to dry and repeat. 

Link to comment
Share on other sites

Dog hair burns out so to not sweat that. Waste. of time I think to try to remove it. Same with grass from the lawn or any small orgainic materials. They go by by when bisqued. The only reason to remove them is if they get in the way of making whatever you are making (forming).

Link to comment
Share on other sites

@Ja.Sc. I know you asked Pyewackette, but I also am grossed out when I find hair in my reclaim and have a dog. A second sheet can help keep the hair out, along with covering your reclaim buckets and keeping your hair well tied back so it doesn’t get into the slop bucket.

A cover sheet on the reclaim can also help the slab dry more evenly, especially if your humidity is really low. It’ll slow it down a tad, but nothing major.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.