Reclaim Tray / Pottery Plaster or Plaster of Paris?

[Rick Wise]

I would like to make a "reclaim bat", i.e. a tray on which I can lay wet clay/slip so that the water absorbs out of it for eventual re-use.  Should I use pottery plaster or plaster of paris?  And why?

[Magnolia Mud Research]

2 hours ago, Rick Wise said:

I would like to make a "reclaim bat", i.e. a tray on which I can lay wet clay/slip so that the water absorbs out of it for eventual re-use.  Should I use pottery plaster or plaster of paris?  And why?

Once upon a time, I had the same situation, how to reclaim clay and then dry the clay back to throwing moisture.  I used a set of large red clay flower pot plates, or a large flower pot sitting on a flower pot plate.  These remove water just like plaster, are not as heavy, and are cheap.  And no, the red did not contaminate the white (aka porcelain) reclaim.  

LT

[Callie Beller Diesel]

If your choices are pottery plaster or plaster of Paris, use the pottery plaster. PoP won’t stand up to the level of moisture and it’ll crumble. 
 

I personally lay a bedsheet over my wire shelves and lay slurry out on that. 

[Mark C.]

I like muds solution

but if you are going to make one use only#1 pottery plaster

plaster of paris is not good for ceramics period as far as I am concerned

[Denice]

I made a slab out of POP and one out of  #1 pottery plaster.   Someone gave me the POP,  I have always used #1,  it was one of those I need to use up this POP moments.  I decided to make a slab also the same size out of #1 plaster.   Clay on the POP took forever to absorb into the plaster and after several uses it started to crumble.   I also took longer to dry out.   If someone offered me a bag of POP I would kindly refuse it.   Denice

 

[Piedmont Pottery]

I'm a big fan of backer board, both as a wedging surface and for quickly drying out slop.  They're readily available, inexpensive, and no worries about getting bits of plaster in your clay.

[Melissa F.]

On 5/5/2021 at 11:52 AM, Piedmont Pottery said:

I'm a big fan of backer board, both as a wedging surface and for quickly drying out slop.  They're readily available, inexpensive, and no worries about getting bits of plaster in your clay.

Doesn’t this warp with the moisture and make it hard to wedge?

[Dick White]

1 hour ago, Melissa F. said:

Doesn’t this warp with the moisture and make it hard to wedge?

No, it does not warp. In my experience, Hardibacker brand is the best of the several available brands. Be aware that there are 3 types of Hardibacker - one is 1/4" thick and two are 1/2" thick. Of the two that are 1/2" thick, one is the original Hardibacker which is somewhat absorbent but is not degraded by the moisture; and the other is a new super non-absorbent type. It can be distinguished from the original type both by price (it's more expensive per sheet) and one side of it is lightly sprayed with a red "paint." Get the original for its absorbency, not the red one. The 1/4" stock is also the original type, so choose the thickness that suits your intended usage.

[Hulk]

I've several pieces of backer board that I use for wedging*, they are still very flat after several years of service.

Backer board, likely not for everyone, as the surface is a bit rough.
I don't mind it; I keep my fingernails away from the surface.

The material doesn't move water like plaster (#1 pottery plaster).
For reclaim, I'm using two inch thick slabs of pottery plaster (cast in a cake pan), which will absorb a lot of water; propped up on 1x1" sticks, five sides are exposed to air for evaporation, which helps a bit as well... 

*one for dark/black clays, one for red clays, one for buff, and one for white, all leftover/scraps from tile projects.

Edited November 12, 2022 by Hulk
slab detail

[Pres]

I usually put slop out on a piece of backer board, but really wet stuff I hang in a piece of cloth tied up to hang on a hook. weight in the bag, and the cloth just drains to the bucket below.

For wedging I used to use canvas over concrete. Now with dust concerns, I have covered the same with a piece of 3/4 inch plywood. It took a while to get good at wedging on it, but now it works fine and is easy to clean up. The plywood had a coat of kills on it before I started using it. Left over from some renovation project.

 

best,

Pres

[Kelly in AK]

I have a plaster free studio.

I use both flower pot plates and hardie backer board for dewatering clay (which I do a lot of). The 1/2” board I use is smooth. The 1/4” is rough and gets saturated very quickly, I use it for ware boards after sanding it smooth. My wedging table is topped with two layers of 1/2” backer board and works great. It sucks water out so well I have to wipe it with a sopping sponge if I want to use it as a work surface. No warping. The only chore with the 1/2” is cutting it, and I find that easier than mixing and pouring gallons of plaster.

The flower pot plates also saturate fairly quickly. I have put slop in them and stacked ‘em to save space. 

[shadypark]

On 5/3/2021 at 5:42 PM, Magnolia Mud Research said:

Once upon a time, I had the same situation, how to reclaim clay and then dry the clay back to throwing moisture.  I used a set of large red clay flower pot plates, or a large flower pot sitting on a flower pot plate.  These remove water just like plaster, are not as heavy, and are cheap.  And no, the red did not contaminate the white (aka porcelain) reclaim.  

LT

HI,

I just did the exact search and came across this post from a few years ago.. How has this process been for the last few years, are you still doing this, or would you recommend a different approach?

thanks,

Ken 

[Kelly in AK]

two layers of 1/2” Hardibacker board will give you some peace. No mixing plaster, woohoo! Great to wedge on, dimensionally satble, easy to get. I still use it for wedging and working surfaces, as well as ware boards. Pulls water out aggressively. It will saturate eventually, the same issue happens to terra cotta planter plates which I also use for small batches. Of course it happens with plaster too,