Bakeware clay body

[rmerrell]

Friends,  What cone 5-6 clay body have you used with success in making baking dishes and casseroles?   I am concerned about thermal shock and cracking.  Thank you in advance for your help. 

[Pres]

I understand your concerns with bakeware, but you should not be overly concerned as most ceramic will do well for baking. I have made, used, sold bakeware as casseroles, egg dishes and other items using a cone 6 mid range stoneware clay. My glazes are made to be fully vitrified, thus durable one the ware. However, bakeware like other non metallic ware needs to be brought to temp slowly, not loaded into a hot oven from a refrigerator, Corning made much of its from glassware for baking and the rules were slow heating, and slow cooling, thus no thermal shock. I believe these rules hold for most work that is made of ceramic for baking. 

The clays that I have used are SC 112, 211, and 630. I use those because they seem to fit the way I throw, and like to work. They hold up well in firings and do what I want them to without surprises.

 

best,

Pres

[Callie Beller Diesel]

The usual recommendation is to use a micaceous clay formulated for the purpose. 

I had  mentors who were making cone 10 stoneware work in the 80’s, and they made a lot of casseroles. They had to come with specific use instructions which run counter to how you’re actually supposed to prepare food. The casseroles would survive just fine if you put unheated food in them, and put the casserole into the oven before turning it on, and only put them down on a wooden or fabric covered surface. But if you didn’t do all of those things, it’d crack. My mentors would get a lot of customer complaints about it. 

So I’d do some thermal shock testing if you intend to use a stoneware. Contact your clay supplier and see if they have specific recommendations.

 

[Min]

Callies story is very familiar to me. I used to sell ovenware but after a run of customers complaining of their bakers cracking I stopped selling it. I attached instructions on how to use clay pots in the oven, used a clay that was recommended for ovenware but still there are those who don't heed the advice. Last straw was someone who put a frozen brie in puff pastry in my pot then directly into a 450F oven and my sister-in-law using one to bake frozen battered fish in, again from frozen to 450 or so, only partly covering the base of the pot.  I do still make ovenware for our use but not to sell.

Design of the pots used for ovenware comes into play insofar as cracking too. Rounded edge between floor and wall, really even clay thickness, well fitting glaze etc.

Laguna has charts of which claybodies they recommend for ovenware if that's a supplier you use, page 3 of this. 

 

[irenepots]

A while ago I  sent a question to Technical at Standard Ceramic about their 630 clay and what they meant by something in its online description.  Here's their answer.  Hope it helps

"We would recommend using 630 Stoneware if you plan on making bakeware or any product that might be exposed to heat regularly. The mullite "enhances thermal capabilities," which means that it will better withstand the repetitive heating/cooling that bakeware is exposed to".