As a potter and former art teacher, I accumulated a lot of different size kiln shelves. Sometimes I would find broken kiln shelves in the kiln room at schools where I worked. Some shelves had huge glaze messes on one side of the shelf, but the the other side was in good shape. Sometimes people would ask if I had use for a kiln that was in their basement and free for the taking if I came and carried it away. Sometimes these kilns came with free shelves and other ceramic supplies. Not all of these free shelves fit the electric kilns I had. When I had a little pile of these over-sized shelves, I would rent a wet tile saw from Home Depot and cut them down.
I ended up with these little weird trapezoid and triangle shapes from the cutoffs. I saved them and use them under test tiles and pots where I think the glazes might run a bit.
So in my gas kiln shed I have a pile of these small kiln shelves. In every kiln load I put experimental glazes. These little shelves save me from having to clean up my larger shelves if any of the experimental glazes run off the test tiles or small pots.
Today I applied Lee's Kiln Wash which I get from Axner pottery. This kiln wash does not flake off - EVER! A gallon goes a long way. I used Lee's Kiln Wash in every kiln when I was teaching in public schools and I fired those kilns 3 days a week for the entire school year. It's the only kiln wash I ever use and I know from using it at the bottom of my gas kiln that runs very hot (Cone 14) that this kiln wash is super durable.
The take aways from this post are that Home Depot has wet tile saws that cut through corderite kiln shelves like a hot knife through butter. Small cut off pieces of kiln shelves can be used under experimental or runny glazes - and Lee's Kiln Wash is super amazing and never flakes off!