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How to make a gravity filter out of buckets so I can remover the excess water and pug my clay

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I don’t have a lot of time and I have a Peter Pugger so I don’t have to wedge I have arthritis.  But I want to reclaim my clay and I don’t have enough room to put out boards to let it dry. But a gravity filter sounds good does any one have direction or an image.  I was thinking I would try to make a filter press like a wine press but I wasn’t sure what to use as a bladder.  Any suggestions on what to extricate the additional water so I can pug this clay?

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Hanging the clay in a cloth bag works pretty well - but it's not particularly fast. 

I use a piece of old bed-sheet - I line an empty bucket with the sheet, so there's several inches hanging over the rim.  Dump the clay in, gather the edges at the top & tie a rope around it, then hang from a hook in my basement ceiling, with a bucket under it to catch the dripping water. (Might go faster hung outside on a tree limb, but I'm usually doing mine in cold winter months, so keep it in the basement so it doesn't freeze in the process.)

Other suggestions I've seen, but never tried:

  • Cut the leg off an old pair of bluejeans, and tie or sew the bottom shut
  • On old pillow case

The more water you get rid of before bagging, the faster it drains/dries...  I let mine settle in a bucket for a couple days, and pour the water off - then bag & hang.

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@Rockhopper, In cold Winter months I let the slurry freeze outside in the shop, Then place it in a pillow case hanging  near the heat.  Freezing brings much of the water to the surface, and  when thawing the water drips out quickly. Then take the pillow case away from the heat to finish thawing. I don't have but, so I cut/slam and cone wedge.




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When I was teaching ceramics at the high school level..... We lined 5 gallon buckets with old pillow cases to store the clay to be reclaimed. When ready to dry, we just pulled out the pillow case, tied a knot at the top and set it outside to drain.  If the outside weather was too wet or too cold we put the pillow cases in our utility sink which had a clay trap.  When ready to wedge, we just opened the pillow case on the wedging boards. 

I required X number of studio maintenance from each student each grading period.  Reclaiming clay is little more time consuming in my own studio without the help of all those teenagers! 

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The industrial filter presses that are for clay production don’t use a bladder. Instead, they pump clay slip horizontally  between sheets of canvas and squish the water out. Here’s a youtube video showing a hand crank one from Pewabic, because me describing it doesn’t do it justice. The physical pressing motion of a ratchet style press rather than the outward pressure of a bladder wine press would more closely approximate this action.

If you’re trying to build a small footprint clay reclaim setup that’s essentially a slow, gravity fed filter press, there’s also this article. (if you don’t have a Ceramics Monthly subscription, you can still read 3 articles free a month.) This is what inspired me to just spread my reclaim on a sheet over my existing wire racking. But if footprint is your problem, building small but stackable frames could be a workable solution.

I’d be really curious to see how that turns out.

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  • 2 weeks later...

barrie, it sounds as though you keep your reclaim wet.   you might find it much easier to let thin pieces dry out completely.  thin is less than a 1/4 inch thickness. 

just let a bucket fill up with each session's bits until you have a reasonable amount to pug, could take weeks or days depending on your activity.  these are dry pieces, not partly dry.

every session   put any actual slurry in a separate bucket that has a piece of aluminum grid on top so the liquid falls to the bottom and allows the stuff over the grid to stay there and begin to dry  .  do that at every session leaving a little more wet in the bucket.  look where outdoor grills are sold and the grid as a "grill topper".  just looking at these items will give you enough info to get the right thing. use a plastic spatula to lightly  press down the stuff on top of the grid so some of it will go through and fall into the liquid.  not all of it.  just some every session. as the top dries, move it to the dry bucket, keeping it thin.

the day before you plan to pug all your clay, add enough water to cover the dry clay bits and leave them to soak overnight.  alternate your pugging with some out of each bucket.  pug twice and you should have well blended clay ready to use.  no wedging.  remember that peter puggers store a great deal of clay in the hopper and that is what will come out first.  so pug twice to equalize the consistency of all the clay.

Edited by oldlady
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