The Problem
How to avoid cracking or warping plates in the bisque firing
 
 

I notice that plates on the bottom of a stack can easily crack from the weight of the stack.  When I set them on edge they sometimes warp.

How to do it?

Set them flat, but be sure to support them each at three points.  The three points must start on the shelf below the first plate in the stack.  I use three piles of sand for this. I keep the three points in line vertically, so the weight of the plate pile does not tend to crack the supporting plates below. 

How many plates can be stacked this way?

My practice is to stack up to five or six.  It depends on the strength and weight of the greenware plates.  This saves quite a bit of kiln space compared to using a shelf  for each plate. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

photo © Marvin Bartel Step 1  Before placing a stack of plates on a kiln shelf, I place three piles of silica sand so that the foot rim of the bottom plate is supported (nested in sand) at three places.

photo © Marvin Bartel Step 2 After placing the first plate on the three piles of sand, I place three small bisque fired pyramids on the plate at the same locations as the three piles of sand under the plate. Step 3 Add another plate repeat step 2.



photo © Marvin Bartel Here you can see two stacks of five greenware plates with bisque fired supporting pyramids as vertically aligned spacers.  You can also see small piles of silica sand on the shelf under the first plate in each stack. I am careful to keep all supports aligned vertically to avoid stress on the lower plates.