Bisquing plates

[MFP]

Suggestions on the best way to bisque plates?  I have been firing them upside down in one layer. It works but takes up a lot of room. 

[Min]

Some people like to stand plates vertically in the kiln and propped against a kiln post or other large pots in the kiln. My claybody actually warps at bisque temps if I do this so I will stack plates with squares of cut up firebrick lined up over the footring (or base if there’s no foot) lining the squares of firebrick up with each plate layer. Each square of firebrick needs to be the same thickness. Bill Van Gilder makes similar ones with 2 or 3 parts elk, 1 part alumina hydrate and 1 part fine grog. (Needs to be rolled out to an even thickness and bisque fired before using).

[MFP]

As always, thank you Min for your response. I would be afraid of the rims cracking if I did the vertical stacking.  I have a new design that may bisque better. I finally figured out that the shelves are heating up faster than the pots.  I make shallow bowls with a deep foot that kept cracking. I finally started firing them on inverted saucers and it stopped.  With plates, all I could do was invert them.  I take a ridiculous amount of time pre-heating both fires. So I know it's not that. So using firebruck as spacers? Do I have that right?

[Bill Kielb]

3 minutes ago, MFP said:

I finally figured out that the shelves are heating up faster than the pots.

Actually, shelves usually outweigh the wares so the likely hood of them heating faster is fairly unlikely. Having said that, you have found something that works so I wouldn’t give up on the success. If you have not heard this before then hopefully worth the mention. Sometimes bowls will catch on the shelf and cause uneven expansion and contraction which leads to cracking. The sharper the foot ring, the more weight bearing on one spot and hence more friction. Your fix works for you, so good solution; however using grog or alumina on a shelf is always good practice to allow things to expand and contract at their own rated and not bind - especially bowls, plates, and heavy things in general.

[MFP]

Thanks Bill but these shelves I am using stay hot far longer than the pots. I think it's also the diameter of the bisque kiln-- 18 inches. I have to do a ring at a time preheat because it will heat up too fast. It has 3 inch brick. I need to start using the big kiln more for Bisquing too. The shelves for it are very porous-- not dense like the ones for the small guy. They don't stay as hot.

I have a new shape for plates I am trying. Will see how this bisque goes. Also a new clay body for plates.

[Min]

28 minutes ago, MFP said:

So using firebruck as spacers? Do I have that right?

Yes, that’s what I do. 3 for a side plate size, more for larger plates. I have old junker firebricks, they cut really easily with a handsaw. Use a guide so the spacers are all the same thickness. (usual cautions about silica dust and wearing a proper mask while cutting firebrick). Plates are fired right side up, not upside down.  Spacers I made are 3/4” width. 3/4” height and most are around 1” in length. If you use the book of faces  have a look at Van Gilders page, he made a recent post with a picture of a really tall stack of plates using spacers.

[MFP]

Thanks Min!

[MFP]

I went out and fiddled with them and put them,leaning against a tall pot. Well see how they do.

[kristinanoel]

Min - 

do you happen to have a photo of what you're describing?
I'm having trouble picturing it but would like to try it out. 

 

[Min]

2 hours ago, kristinanoel said:

Min - 

do you happen to have a photo of what you're describing?
I'm having trouble picturing it but would like to try it out. 

 

My studio is packed up as I'm moving soon otherwise I would take some photos of my kilnbrick spacers/blocks. Bill van Gilder images below of his made from the mix I mentioned in a post above. 

 

[MFP]

Very interesting! Where are you moving if I can ask?

[neilestrick]

I just stack them like I would stack them in the cabinet, usually 5 or 6 in a stack.

[Min]

2 hours ago, MFP said:

 Where are you moving if I can ask?

Staying in British Columbia but moving closer to the ocean. About a 10 minute drive to the Canada U.S. border which is nice too!

[MFP]

Sounds wonderful! I hope you have an uneventful move! I moved my studio into my garage last Fall. I saved the money I paid the movers not having to buy propane! I visited Mark in McKinleyville. I was looking at the area in case things here get just too crazy. I sure would like to live in that area by the ocean. 

[Pyewackette]

So is this akin to tumble stacking?  That sort of Yertle-the-turtle layering looks scary to me, but maybe that's because I'm not totally sure yet that something I make might 'splode (well crumble or at least crack) in the kiln and bring the whole towering pile tumbling down.

[Callie Beller Diesel]

Some of it will depend on your clay body and the shape of the piece. If I did a plate stack like the one in Van Guilder’s kiln with my clay and plate shape, the bottom couple would crack like you’d expect a waster to. But mugs seem to be fair game to do this with. 

 

[MFP]

The leaning them against a tall pot worked great! Thanks Min!

[oldlady]

recently fired a very flat piece leaning against a kiln post.  one of the square kind, i usually fire with the small triangular posts to save room on each shelf.  thank you marcia selsor for showing how you lean your bisque pieces.

[Gonepotty]

On 4/24/2022 at 3:52 AM, Min said:

Yes, that’s what I do. 3 for a side plate size, more for larger plates. I have old junker firebricks, they cut really easily with a handsaw. Use a guide so the spacers are all the same thickness. (usual cautions about silica dust and wearing a proper mask while cutting firebrick). Plates are fired right side up, not upside down.  Spacers I made are 3/4” width. 3/4” height and most are around 1” in length. If you use the book of faces  have a look at Van Gilders page, he made a recent post with a picture of a really tall stack of plates using spacers.

Hi Min, 

What temp can the firebricks be fired up to? Looks like a great solution for bisque 

[Min]

46 minutes ago, Gonepotty said:

Hi Min, 

What temp can the firebricks be fired up to? Looks like a great solution for bisque 

If you get a firebrick from your ceramic supply place it will be fine for this. K23's are what most electric kilns are made with and they are rated to 2300F/1260C but there is a fudge factor there and they can go higher. K26's are rated to 2600F/1427C. (Industry makes a range of firebricks for different applications / temperatures)