64. How to Fire Lidded Jars

[@tombraun7235]

Thanks for sharing! I had mixed experiences with glazing stuff upside down (or better: the opening touching the kiln shelf). When the walls of the pot are quite thin, I had pieces warp in the past (even stoneware) and switched to firing them together with the matching part. My theory is, that it is because when the pots shrink during the firing, there's uneven drag on the kiln shelf and the pieces might get bent out of shape. But I found that this is only an issue with thin walls or when pots are taller than they are wide. In case of your fermentation pots, you could even fire them with the knob on the kiln shelf and glaze the whole rim. Anyway, your pots turned out really great and I love your videos!

[@deMibPottery]

Thanks a lot :-) Yes, that may be a contributing factor too. In this case - with the fermenting crocks, my goal was to be able to glaze the gallery as it have to hold water. And that turned out as intended.

[@petergregorypottery5476]

Thank you :-) I often fire my lids separately, because I worry less about them warping than what would happen if they stick to the pot! I think that firing separately works well when firing in an electric kiln, because the temperatures are relatively even, but when I fire in my wood fired kiln I do try to fire the pot and lid together separated by wadding, because the heat distribution is much less predictable. In my electric kiln I would usually fire the pot and the kiln on the same shelf if the lid was a good fit when it was made, but if the lid is slightly loose, I can sometimes correct this by firing the lid and the pot on different shelves. The bottom shelf in my electric kiln is just over half a cone cooler then the rest of the kiln, so fired pots there shrink very slightly less than in the rest of the kiln. I can use this temperature difference to make minor adjustments to how well the lids fit!

[@deMibPottery]

Thanks. Good points! :-)

[@edwhite8162]

Also try putting a layer of sand under the lid when you glaze fire. Sand acts like ball bearings and allows the whole lid to shrink naturally in the fire. Less warping always. Also works for plates and other flat bottom pieces.

[@deMibPottery]

Thats an option too but I never had that issue here, with my plates and lids :-)

[@xm3364]

Hi Mikkel, thanks for the testing recorded. Seen potters done both. Not wrong that you told other is fired lid and pot separately. I believe if there is room on the gallery it would be safer to fire in 2. Most of the lids or gallery just warped and they dont fit like they used during bisque. Worst on my piece in porcelain, the lid was ok but gallery was bent- where the handles were. Was told that the handles weighed the gallery down... I know probably the gallery wasn't spacious as well... Any a shame, it was a very pretty pot.

[@deMibPottery]

True, as mentioned there can be exceptions. Just good to know that sometimes it works :-)

[@lynnenewell6812]

Thanks for breaking the myth - will try with mine. It’s like I now always bisque fire my plates on their sides against the kiln wall and never get cracks or warping anymore - pure physics if you think about it! Cheers from Lynne in New Zealand

[@deMibPottery]

Glad to help :-)

[@gigi3242]

Thank you for the video, for questioning, for having fun and sharing it with us. Be well

[@deMibPottery]

Thank you so much :-)

[@micass3561]

Just tried this and warping happened. I think you have to have a certain type of lid and/or clay to fire them separately. Thanks for the video. :)

[@deMibPottery]

Yes, and also your fire schedule. In general it should work with most stoneware :-)

[@lynnenewell6812]

So bisque fire together but glaze fire separately? Thanks again and sorry for all the posts - just trying to get it clear in my head 😂

[@deMibPottery]

Yes, thats what I do and it works well for me :-)

[@lynnenewell6812]

Did you fire the same lid and bottom on the same shelf to get the same heat or does that n or t matter? Thanks Lynne NZ

[@deMibPottery]

It's been a mix. Some of them on other shelfs - some on the same. Seems to work OK :-)

[@ludouglas1]

I have fired separately and every time, they don’t end up fitting. :-(

[@deMibPottery]

The potter I mention in the video have made hundreds lidded jars, all fires separately and all fitting well. I just did this one test with 5 jars and they turned out well too. But as I mention there could be other variables too. Maybe a kiln that is not firing evenly enough. Maybe some issue with how they are thrown. My point with this video is just to show that it IS possible and that open up new options that I love :-)

[@ludouglas1]

Hello again :-) yes, it’s the variables that are unaccounted for. Have a fabulous day. Thanks for replying. Xx

[@imolourembam7111]

How to dried and how long

[@deMibPottery]

It is important it is completely dry before fire. How lond it takes depends very much on clay thickness, drying temperature and humidity. This one I let try a couple of weeks at room temp and himidity