Why Are My Plates Exploding???

I bisqued a load of pots a couple of days ago. When I opened the kiln this afternoon I noticed several of the plates had literally exploded. These plates were ones to which I applied slip. I threw the plates using Highwater Raku clay and then put Highwater Helios porcelain slip on the inside of the plates. I'm 99.99% sure the plates were completely dry at the time of firing. They had been sitting on a shelf in the studio for over a week (in Florida with no central AC).

Has anyone experienced such a problem? Could it be a difference in shrinkage rate? Could it be that some moisture was still present?

Any help is greatly appreciated!

New Stuff

I finally got the studio organized the way I want it. To be more specific, after lots of trial and error, I have discovered how much stuff I can get in there and still have space to work. I now have most of my tools located within 'reaching distance' of my wheel. No more walking across the studio with clay-covered hands to get something


I recently bought a large metal shelf with wheels. Very useful:


I liked the large cart so much i bought another, smaller metal cart to hold slip, terra sig, and miscellaneous other items:


Here's a closeup shot of the small cart. It holds slip I made for each type of clay I use: Zella Stone, Loafers Glory, Raku, and Helios (all Highwater Clays). Additionally, I created a mixture of Helios porcelain with red iron oxide (8% RIO). On the bottom shelf is terra sigillata as well as some Magic Water I use to connect clay (mainly for handles).


I recently ordered some new tools from Kentucky Mudworks. They carry a line of tools made by 'Dirty Girls Pottery Tools'. I have found them to be very well made. I bought two sling shot tools, one is a straight wire and the other a wiggle wire:


The other tools I ordered were the 'Great Big Facet Tools'. Again, one straight wire and one wiggle wire:


I love the roller on these facet tools. I can't wait to use them.

I have some more things to post, but it will have to wait until tomorrow. It's getting late and I can barely keep my eyes open. Goodnight!

Terra Sigillata

Today I made a batch of Terra Sigillata. To be accurate, I made it yesterday and harvested it today.


I've been wanting to test some slip on raku ware. I made some small test plates with slip in the middle. My plan is to cover the slip with a copper black glaze and put a copper/green glaze on the remainder of the plate. I hope to fire this in the next couple of weeks. I will post my results.


I threw a stoneware plate and once again put some slip in the middle. This time I put a layer of helios (porcelain) slip with red iron oxide around the remainder of the plate. Not sure which glazes I will use on this one.


I've discovered when applying slip a little thick (as in the photos above), you must do the following:

1. The slip must not be too watery, and
2. You must dry them very slowly

Otherwise the slip will crack.

I recently purchased a couple of paint sprayers and I am about to get into spraying glaze. Until now I have only dipped and brushed. My friend John Tilton is going to give me a few tips this week at his studio. I'm looking forward to it!

That's it for now but there are currently a lot of things taking place in the stuido. There should be more postings very soon. Thanks for reading!