Reclaiming Large Volumes Of Slop

[hitchmss]

So I checked the previous forums to see if there was one that dealt with this topic directly, and I could not find one so I apologize if this is a duplicate.

      I need to find a new way to reclaim my throwing slop; for years when I wasnt making large amounts of pots (1-2 tons year) a large plaster slab or concrete floor worked fine. Ive been making production pots for the past 5 years now and make around 6-8 tons of pots/yr and create about 5 gallons of slop every other day during production. My studio is quite small (about 250 square feet) so real estate cant be consumed by countless plaster slabs which is what I started using 5 years ago only to find out that it took too long and too much space(even stacked up). About a year or so ago I made myself a kind of "gravity filter press", essentially some cloth hung between a wooden frame to dry clay; this method worked ok up until the other day. I came into the studio and found some really lovely bright orange mold growing on my clay/cloth/frame; pulled the cloth back to show the even lovelier black mold growing on my 2x4"s. Obviously this is unsafe for the studio and needs to be remedied. The issue with this setup is that it takes week(s) for me to dry out (even with running a dehumidifier constantly) a bucket of slop poured into this frame, which provides the mold plenty of time to grow. I have a large Peter pugger, and use it to process my new clay and scraps, but I try to stay away from bags of dried materials for the fact that I dont have any source/site ventilation (or room for more ventilation) at my pug mill and dont want to be adding even more dust to my atmosphere. Ive tried this method (using bags dried clay body to dry out reclaim) and found that I need about 70# dry to one 5 gallon bucket to get close to being the right consistency(too much powder/dust for my studio/liking), and then it also kills my plasticity.

    Aside from remaking my "filter" frame with a non organic/non mold promoting material such as steel/pvc, and lining it with a non organic fabric, or using bags of dried materials and my pug mill does anyone have some good ideas? Ive seen folks reclaim smaller amounts in nylon hosiery/old jean legs/cheesecloth hung out to dry, but I dont have the room to hang all that. In school where we had tons of room we'd use the big soldner/blue bird mixers & ventilation to dry out reclaim, but no space here for that.  If I had a large concrete slab which I could pour my slop onto Id do this, but I dont, and even in the winter(Ohio) Id be out of luck. I know a lot of high volume potters save their year's slop until the summer and use the "gravity filter press" idea to dry out large volumes in days instead of weeks,  but I dont have the space to be storing all that slop. I already save my trimming scraps and can use a bucket or so of those to dry out a bucket of slop in the mill, but that only goes so far.

    I know this is an issue which plagues all potters and studios and aside from the methods Ive mentioned Ive never seen another method which worked well(at least methods which are applicable for smaller personal studios compared to factories).  I'm hoping someone has seen a clever solution that will work for the spatially challenged, high volume studio. Maybe there isnt a better method and I'll just have to learn to abate/deal with the mold, but Im hoping there is.

   Thanks for any ideas!

Sam

[Benzine]

Sam,

 

I've never worked in the scale, that you are, but I have had several sections of Ceramics going on at the same time.

 

The classroom had a pugmill as well.  What I would do is use the mill to mix together the throwing slop/ any other slip, and the drier bits of clay the students had left from making their projects.  If you are only throwing, you probably wouldn't have a lot of scraps, but no doubt you have some.  I would also come across bags of unopened clay, that had dried a bit, so they were no longer good for throwing.  Those would get cut into bit, and pugged with the slop as well.

 

The system worked pretty well, in my opinion.  

 

In my first classroom, we hand reclaimed everything.  We took sloppy wet clay from mixing scraps and water, and worked dry clay powder into the clay.  Why did we do this?  Because I was new to teaching, and that's the way the previous instructor had done it.  In retrospect, I would not have done it.  The classroom had a pugmill, that I tried to use, but it ended up taking way too much time.  Small hopper, and just a slow machine in general.

 

Currently, my classroom has no pugmill.  We hand reclaim everything.  I have a slip bucket, that when full, gets mixed to a smooth consistency, then poured into a plaster mold.  That gets wedged and put into a bin, with some drier bits.  Students mix the slightly wet with the slightly dry, by using their cutting wire; cut, stack, wedge, repeat.  

 

Sooo, I would just go with the process I first described.  Mix the slop with slightly drier bits in the mill.  Then store the pugged clay.  DO NOT use the clay powder.  It's not worth the headache.  Any bone dry bits can just be slaked down in your slip or slop container(s).

 

Do you bag your pugged clay, or put it in a large bin?  I've always gone with the bin method.  The large "Brutus" Rubbermaid garbage cans.  My college did the same thing with their reclaim (Except they added coarse grog into their reclaim...  The side of my hand still remembers throwing with that stuff...).

[oldlady]

sam, how about throwing very dry and not producing so much wet "slop"?  sounds simplistic, i know, but maybe it is a way to avoid most of the problem.

[Denice]

My first throwing teacher taught us to throw wet the second had us throw dry.  Loved throwing dry and very little mess or slop.   Denice

[Mark C.]

Sam you have the right tools just not the space. I assume your peter pugger is a vacuum model?

I use my Peter pugger with only wet materials /scraps. I toss out all dry trimmings-not worth the time to process them.

How about drying some regular clay to a harder state and adding that to your slop in mixer.

since you have a mixer its just a space issue-you could also do what I did long ago and freeze dry your slop outside-the freeze will force water out of it-bring it in and run it thru the pugger-it makes clay short so you need some wet slip clay to age it so it has legs.

[hitchmss]

@Oldlady & @Denice, I throw, what is in my opinion, fairly dry. Depending on the item being made I can usually make a gallon of fresh water last between 50-100 pots of said item. I dont like when my throwing water gets too "slippy"; it ends up leaving me with more muddied surfaces than I prefer. I throw on a pacifica wheel (fairly small splashpan) and I dont have to empty my splash pan for about 10-14 days of serious throwing. Most of my slop comes from my ribbing the inside & out of most of my pots. Ive heard of some potters who can throw with next to no water and get fairly thin and consistent pots; I find that I can throw faster, and more consistently thin pots by using a little bit more water.

 

@Mark.C; Yes my Peter Pugger is a VPM60. I too have considered not even bothering with my reclaim. At the volume I buy clay I usually end up paying about 25-30 cents/lb, so sometimes when I consider that Im consuming space and my time, usually getting shorter clay, its cheaper just to donate or throw away all scraps. I could dry out some blocks of clay but would probably end up taking up so much space drying blocks to then consequently dry out my slop that it would take up too much space. I use my trimming scraps in the essence of this method which helps; I find a packed 5 gallon bucket of trimmings will dry out to consistency about 3/4 of a 5 gallon bucket of slop. Since I dont trim a ton of my pots I never have enough scraps to dry out all my slop. 

    The freeze drying method is one Im not familiar with? Were you leaving your slop in the buckets, freezing outside (forcing water to top), removing ice/water, then thawing, then mixing? You werent milling frozen clay were you; at least I assume not frozen solid? Ive had problems with most of my reclaim being fairly short; Ive added some bentonite at times to improve its plasticity but found its limited in results; aging is best allowing the particles to thoroughly wet and ameliorate, but I dont have room to store too much clay. I have room for about 1500 # under my throwing table which is the only space to store clay. You did hit the nail on the head though; lack of space is my biggest issue; we are trying to move into a new, bigger studio but time and money as always....augh!

 

@benzine; My clay once it comes out of the mixer gets used almost immediately. We dont have room for a big bin or trashcan (did the same thing as you in college); the hopper on my mill holds about 125# and we'll go through 100 on a slow day, 200-300 on a super busy day. In my early college years I used to throw with a clay body that was almost 12% grog(C,M,&F), and another 10% fireclay in the youthful idea that I would be able to throw gigantic thin pots with ease; I learned more that literally bleeding for your media was not a good sacrifice for time earned skills. Taught me right quick not to ride the bats and use as little surface area as possible though; I guess all misguided ideas have some benefit....somewhere.

[MatthewV]

Mold issues can be treated with a tiny amount of copper carbonate. I add a little bit to my reclaim and it removes all the funky smell. (like 0.5 gram for 30 gallons of clay). I would also spray any problematic looking molds with a dilute copper carbonate solution.

 

I would also say a bucket in a bucket filter (all plastic construction) is a better way to keep the gravity filter.

 

You could also make a rack to hold multiple ~2" plaster slabs to dry the clay on.

 

But it sound like you really need to lease a shop with more space.

[Mark C.]

If you are using large volumes like me your time is not worth the hassle of reclaiming lots of clay.

The freeze method I used over 35 years ago and that was as reading slop clay on metal corrugated tin roofing in layers like a cake -exposing it to freezing and when it was removable taking it back inside to work with it.

I would never dream of doing this today.

Now my VPM30 just gets my wet scraps only and makes hard clay softer or mixes two soft clays to make a new body-all porcelains.

If your reclaim is short add your throwing slip  to it in mixer as it has the right stuff in it to help the shortness

Dry clay will also make it short mixed with wet-then it needs to age.I no longer age clay or work to much with it as working with 10 tons a year-the clay is the cheap part.My Time is not. 

You never said what type go clays your using ?

[hitchmss]

Mold issues can be treated with a tiny amount of copper carbonate. I add a little bit to my reclaim and it removes all the funky smell. (like 0.5 gram for 30 gallons of clay). I would also spray any problematic looking molds with a dilute copper carbonate solution.

 

I would also say a bucket in a bucket filter (all plastic construction) is a better way to keep the gravity filter.

 

You could also make a rack to hold multiple ~2" plaster slabs to dry the clay on.

 

But it sound like you really need to lease a shop with more space.

Yes I need more room desperately; leasing isnt something I believe in but we are shopping around for a suitable building in the right price. I like the idea of a bucket in a bucket gravity filter idea; simple and non mold prone; I might have a tough time separating the buckets after drying some slop out. Do you have any experience with this method? Drilling some kind of holes into the bucket to allow water is the natural thought process but too big a hole and the slop is just gonna run right through and too small wont allow water to escape. Maybe drilling larger holes and using a house wrap or other "breathable" fabric thats not organic to line the bucket with first.

    Unfortunately because of my lack of space Id have to lift heavy plaster slabs loaded with slop up high onto a rack if I were to build one. My current slabs are ~2" thick 2'x2' and probably weigh 30 # on their own. ive used blocks of wood to space out numerous slabs on a table top but, space again is a premium.

 

If you are using large volumes like me your time is not worth the hassle of reclaiming lots of clay.

The freeze method I used over 35 years ago and that was as reading slop clay on metal corrugated tin roofing in layers like a cake -exposing it to freezing and when it was removable taking it back inside to work with it.

I would never dream of doing this today.

Now my VPM30 just gets my wet scraps only and makes hard clay softer or mixes two soft clays to make a new body-all porcelains.

If your reclaim is short add your throwing slip  to it in mixer as it has the right stuff in it to help the shortness

Dry clay will also make it short mixed with wet-then it needs to age.I no longer age clay or work to much with it as working with 10 tons a year-the clay is the cheap part.My Time is not. 

You never said what type go clays your using ?

I primarily use Bmix, but also use a couple of other stoneware clays for platters, bakeware, etc. I agree wholeheartedly, clay is cheap but my time isnt. Its just hard for me to think about throwing away something I could use again. Maybe in the short term until we move into another studio Ill just have to forsake recycling the slop and in the future when more space is abound revisit a method of drying the slop out. As i was throwing today I was thinking about making some kind of actual filter press(not relying on gravity) using a 5 gallon bucket. Ive never seen a home built press like this but maybe some googling will turn up some ideas. If I could take 20 minutes to press the majority of the water from my slop it would go a long way to reclaiming.

[hitchmss]

Thanks for the feedback so far from everyone btw

[Mark C.]

My clay drying days was mostly with stoneware.I had a large plaster slab out side out of the rain and I dried the slop there -as soon as I could handle that 50# slab I took it off and let it air dry in tin roofing  (thats when the fees dry worked)(we also had freezing almost every winter-now thats not the case-with climate change) and started another batch-back then I ran it thru a vertical alpine pug mill and kept it on the wet side as time always dries clay out. reclaiming takes space-if you have none forget about it until you do have space.

I throw 1-3 5 gallon buckets a week out myself-never thought much about it.I would like to use my old car tires as well but I just have new ones put on and have the old ones thrown out-Its just like that really-Now I use the wet clay scraps but todd the dry trimmings-I used to use it all and that took time an space .I got smarter-now its going the other way.

 

One last note about short clay-I have heard from more than one source about b-mix getting short on the reclaim-I do not use it myself much so I cannot verify this but something to know.

[GiselleNo5]

Mark, I have heard the same thing about B Mix. I am about to reclaim my first batch of it. I'll let you know how it turns out. If it's bad I will not bother reclaiming any more. I don't waste that much and I have a feeling it's not worth the time it will take me to reclaim it. 

[hitchmss]

Mark & Giselle,

    Ive found that Bmix will reclaim fairly well and easily. Dried out on a plaster slab or concrete provides almost like new results. When I use my pug mill I add trimming scraps/dead bone dry pots and dried out (still super soft) slop; I usually do this as my last batch of the mill for the day so I can let it sit overnight. Ive found that not only will the added time with the moisture help break down any larger bone dry chunks that the mill wasnt able to "crush", but improves the plasticity by a bunch just for sitting for 8-12 hours and ameliorating.

    When ive used bags of dry mix to add to my slop in the mill the resulting clay is so short that it "rips" coming out of the mill's nozzle, and you cant bend a finger thick coil even halfway around your finger before breaking. I believe the lack of plasticity comes from the fact that most bentonites (and other similar plasticizers) need to be wetted and blunged before adding to your mix for best results. I would venture to say that the scraps work better than dried powder because all the material being processed has at one time been wetted and thoroughly mixed.

   I know some folks think of bmix as being a difficult body to work with, and it does have its nuances, and maybe Im biased after working porcelain for 10 years, but I think its a relatively easy "porcelaineous" stoneware to work.

[notjustanybeth]

I don't know how well this would work with large volumes, but what about putting the mixed slop in cloth bags inside largish earthenware (or maybe bisqueware?) planter pots, which already have holes in the bottom, and may absorb some of the moisture? I would suggest not using the bags and just putting some newspaper or something on the bottom, but I am not sure how easy it would be to get the clay back out again.

[Biglou13]

reclaim your slop outside?

[Babs]

Cheap shop pillow cases hanging under verandah, dripping in to buckets.... Think legs of old jeans also been used..

YOur back should be precious, lifting heavy weights above shoulder height asking for no longevity.

[Mark C.]

Babs that must be why my back starting hurting when I was in my 20's and has never let up much. It was not clay filled pants ever or even pillow cases as I have always like down feathers in my pillow cases. I think its been all the clay and bricks and bags of materials and show pots and setups and take downs-Did I mention the clay weights? I think I handle a pots like 10-12 times before I hand it wrapped to a customer . 10 tons a year 10 times for many decades my god I should just fill MY pants with clay and sell them a squirt out the pant leg. Let them discover the joy of wet clay in your sock and shoe.

[TallTayl]

<snip> I might have a tough time separating the buckets after drying some slop out. Do you have any experience with this method? Drilling some kind of holes into the bucket to allow water is the natural thought process but too big a hole and the slop is just gonna run right through and too small wont allow water to escape. Maybe drilling larger holes and using a house wrap or other "breathable" fabric thats not organic to line the bucket with first. <snip>

Instead of one pail "inside" the other, put one pail "on top of" the other. You can Use a lid with a hole cut into it on the bottom pail, or a board to allow the top pail to drain into the bottom without jamming them together. It does not take long to drain, then the water can be used on the next pail to wet reclaim

[ronfire]

I pour my blended scraps into a pillow case and lay it on the concrete floor flipping it over every couple of days onto a dry spot.

[Pieter Mostert]

There's a potter called Dan Weaver who has a series of

on how to de-water slip using a filter-press bag inside a vacuum bag attached to a vacuum pump. It'll take a bit of work to set up, but it looks like quite an efficient way of doing things.

[Babs]

Well Mark, Early morning belly laughs make for a good day.

Now why did you buy an extruder when you could have been using your jeans all along. Makes for a different meaning of wedgie!

Clay weights?? have you got a market for these at the nearest city gym? I guess they lift weight above the shoulders in those places, never ventured into one of those places, too busy working with clay, but it sounds like a restful pastime.

Now serious recycling slop.

I donated a lot to a local kids club and they made a clay slide down an embankment into the ocean......the slop did contain Tyler's brew AND silica....oops

[perkolator]

I'd personally end up doing what I saw in a Korean onggi video if I didn't want to deal with dust or small 5-gal reclaim batches.  If you can do it, store your reclaim in trash cans and wait until the weather clears (or do it somewhere indoors i suppose).  They can be outdoors since you said no space inside.

Simply pour/scoop out your reclaim slurry onto a big plastic sheet/tarp, let it evaporate to the consistency you like, then cut strips and roll it up like sod grass.  Run these through your pugger and store them/use them.  To me it seems like much less work than doing smaller batches.

[GiselleNo5]

I tried the pillowcase method with disastrous results. Never again!! LOL

[Chris Campbell]

Just out of pure curiosity ... Is there a success rate differential between fresh clay and reclaim? Is it really worth adding extra costs into the end product?

[Biglou13]

Just out of pure curiosity ... Is there a success rate differential between fresh clay and reclaim? Is it really worth adding extra costs into the end product?

 

are you speaking of increased labor costs? by reclaiming clay?   im not a production potter, making and reclaiming clay is part of hobby and enjoyment for me

I'd personally end up doing what I saw in a Korean onggi video if I didn't want to deal with dust or small 5-gal reclaim batches.  If you can do it, store your reclaim in trash cans and wait until the weather clears (or do it somewhere indoors i suppose).  They can be outdoors since you said no space inside.

Simply pour/scoop out your reclaim slurry onto a big plastic sheet/tarp, let it evaporate to the consistency you like, then cut strips and roll it up like sod grass.  Run these through your pugger and store them/use them.  To me it seems like much less work than doing smaller batches.

im not a production pottter but i process slop and trimmings with a friend. we use a hardware screen table.   we save slop and trimmings, sometime harder chunks, in 5 gal buckets which get transferred to plastic garbage can,  we slurry mix with mud mixer/drill ocasionally throughout wait,   when can is 3/4 or so  full we place old sheet on drying drip table, when at proper consistency pug