[pattial]

Can someone explain what happens to the clay particles when you use a slab roller? And why does using a rib on the slab helps. Thanks

[bciskepottery]

As the slab goes through the rollers, the clay particles are aligned right to left. Structurally, that is a weak alignment as all the particles are aligned in one direction. Ribbing, or passing the slab through the roller again but turned 90 degrees, realigns some particles so that the overall alignment is more integrated, cross-hatch. You can also use a rolling pin to roll the slab in all directions. Doing so helps reduce warping and makes the slab stronger.

[pattial]

Thank you

[Chris Campbell]

The top and bottom of the slab roll through at two different rates as well, so it might pay to flip it too.
( I tested this by using identical colored clay patterns on both sides and found one side stretched almost twice as much as the other)

[Pres]

Chris Campbell, on 22 February 2013 - 10:52 AM, said:

The top and bottom of the slab roll through at two different rates as well, so it might pay to flip it too.
( I tested this by using identical colored clay patterns on both sides and found one side stretched almost twice as much as the other)

This makes sense, as when watching a slab roller you notice the bottom does not move as much as the top. I would often roll a slab with less shim, then turn sideways and roll with full shim. this helped to give a more consistent nature to the structure. Large slabs couldn't so just flipped 180. I always believed that squeegeeing just smoothed the surface.

[Marcia Selsor]

My slab roller has dual rollers. I prefer that to shims. and I do rotate the slabs. My roller is 30" wide. I have boards that I slide under the slabd to flip them and remove them from the table. My raku slabs fired on edge stay flat.



Marcia

[mrpeders]

Marcia Selsor, on 22 February 2013 - 11:27 AM, said:

My slab roller has dual rollers. I prefer that to shims. and I do rotate the slabs. My roller is 30" wide. I have boards that I slide under the slabd to flip them and remove them from the table. My raku slabs fired on edge stay flat.



Marcia

I recently purchased a 24" tabletop NorthStar slab roller. The instruction I received at my local studio has a huge roller that rolls over boards that control the depth of the slab. My roller does roll the clay between two rollers. Please describe steps to exactly how you roll your slabs. How important is the flipping, rotating, ribbing, etc. I usually seem to have a slight warp in slab built work. How thick are the slabs you use? Would that also work in an electric kiln? Thank you kindly for sharing your knowledge.

[Marcia Selsor]

I don't flip them to roll through the slab roller, just to smooth the finished side for drawing and flip to add nubs for hanging wire. I wax the edges to also avoid uneven drying and dry them on sheet rock with a piece of newsprint between the clay and the gypsum. The sheetrock edges are taped to keep the gypsum from shedding in the studio.
I believe two rollers compresses both sides of the clay rather than one side using one roller.
I bisque them on edge and fire them in the raku kiln on edge. I don't lean more than 3 or 4 against each other in the bisque and I line up the nubs so the pressure is lined up through them. They are glazed in Raku leaning against bricks.

http://ceramicartsda...ewimage&img=849

Marcia

[clay lover]

Marcia Selsor, on 22 February 2013 - 03:17 PM, said:

I don't flip them to roll through the slab roller, just to smooth the finished side for drawing and flip to add nubs for hanging wire. I wax the edges to also avoid uneven drying and dry them on sheet rock with a piece of newsprint between the clay and the gypsum. The sheetrock edges are taped to keep the gypsum from shedding in the studio.
I believe two rollers compresses both sides of the clay rather than one side using one roller.
I bisque them on edge and fire them in the raku kiln on edge. I don't lean more than 3 or 4 against each other in the bisque and I line up the nubs so the pressure is lined up through them. They are glazed in Raku leaning against bricks.

http://ceramicartsda...ewimage&img=849

Marcia

I have the Slab Master, with 2 rollers. It has a wheel adjustment that adjusts the space between the rollers. If I'm wanting a rather thin slab, I run the clay back and forth , dialing the rollers closer and closer together each pass. I think it would strain my gears to try to go from 3" to 1/4" in one pass like the Baileys can do.

Does working that way increase the compression?
Do I still need to turn the clay 90* ?

[Marcia Selsor]

yes. it is a good idea to rotate the compressed slabs.
Marcia