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  • Kiln underfire

    Hello all. I have made a big mistake (maybe). I have just repaired my skutt 1227 kiln. While it was down, i fired in a smaller kiln. anyway, i shifted a load to the big skutt and fired. when opened, i saw I had severely under fired the load. what happened is that I had put a bisque cone (03) in the kiln sitter to test the skutt and forgot to replace it with a glaze cone (cone 6) so, basically, I fired a full load of cone 6 glazed ware to only 03! Will it refire ok if I put in the proper cone 6 cone and fire again? thanks!

  • #2
    it's been years since I did pottery in a kiln myself but all I can say is, if the glazed ware is already ruined, is there any harm in putting it back in at 06 and seeing what happens???? from memory the worst that can happen is that the glaze may not come out the colour that you intended it to be.

    Personally I would put it back in at 06 and see what happens, you never know you might find a pleasant result!!!! Let us know what happens!
    Diane
    Reach for the moon-if you miss-you'll still be amongst stars




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    • #3
      Has the glaze started to melt at all?

      I dont think it would be a problem to refire back up to the correct temperature. The glaze doesn't usually take effect and do its stuff until it reaches certain higher temperatures, so if its only been fired up to bisque, say about 1000 degrees, it should still work ok.

      But as Moonbeam Angel said, the glaze may not come out exactly how you had planned, but I would say it would be pretty close. Anyway, opening a kiln after a firing is always a surprise! You never really know what the end result may be.

      I love happy accidents

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      • #4
        Have to agree about happy accidents, I remember once, we had a holly leaf dish that we glazed green. We ran out of one glaze and my mum did the final coat of glaze with another green (same colour different make) not realising that the make up of the glaze would be different.

        The result was a very attractive varigated leaf which we ended up having to repeat time and again as it was a better seller than the plain green!!!
        Diane
        Reach for the moon-if you miss-you'll still be amongst stars




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        • #5
          reporting back

          Hello all and thanks for the replies. I refired and have results. I fired to the correct temp, cone 6 (not 06). the load came out ok! I did not really add much info in my first post. I have been potting for 15 years, hand thrown stoneware, and make my own glazes.

          Over the years, I had once started to fire a glaze load and had it shut off at low temps without problem. But I also had a malfunctioning kiln that did not quite make temperature and the glaze was awful and did not improve with a refire.

          I lucked out this time, the real question was did I fire it high enough to burn out some of the glaze chemicals, so they began to change or not? It must have been close, because some of the colors are more matt than usual and some look normal for the cone 6 firing. I believe the difference is in the colorants in the glaze, since the base glaze in all of my glazes are the same. My solid white piece with tin oxide as the colorant is very matt, while the gold/brown, with red iron oxide is nice and glossy. a vase with blue on the bottom and a green and black combo on the top has a matt bottom and super glossy and fluid top.

          I had moved my shop last year and am still renovating and trying to work too, it has been a bit rough. it is good to have my big kiln back though.

          again, thanks for the replies. you both were basically on target.

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          • #6
            Hi Steven,

            Those results sound rather nice! I like the sound of matt and shiny together on a vase.

            You should stick around here and make it a common thing to come and chat to us, also to share knowledge and pick up great tips, but not just about pottery!! There are very few potters on here

            Would love to see some images of your work too

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            • #7
              I agree please keep in touch with anything and everything, we would love to hear more. (just nosey!!)

              I also think the matt and glossy glazing sounds fab!
              Diane
              Reach for the moon-if you miss-you'll still be amongst stars




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              • #8
                I will try to come around a bit. I will see if I can get a pic or two of the pots from the kiln. thanks Moonbeam and Hupfield ceramics!

                Thanks for the help.
                Steven G.

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                • #9
                  alter their chemical state and then when you refired

                  Hi Steven,
                  what has probably happened is that you have heated the glaze chemicals enough to alter their chemical state and then when you refired them again the crystaline structure was slightly different so they did not react as much with the glass maker/flux part of the glaze mix.

                  A common example of this is Temakou glaze which contains iron oxide and fires brown to nearly black. However refire this glaze and you can get yellows appering!

                  Robin
                  www.toppotsupplies.co.uk

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                  • #10
                    Thanks for the replies. I do think it had altered the composition a bit. I just did not know how much or if it had gone too far to save. I would guess with all the variations in glazes the only way to know for sure is to fire and then open up the kiln and see. I tried to post a couple of pics, but the site would not let me until I have made 25 posts!

                    again thanks
                    Steven G.

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                    • #11
                      The first time i get interested in pottery is when i meet my husband, because he told me that his mother did pottery. So when we get married i often visit my inlaws house and i saw different color of bowl and i love it so i get interested in pottery. I haven't started yet, but reading replies, i got some ideas how it works. Thank you
                      Mod edited signature - crafts only................dentists???

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                      • #12
                        Get chatting more to build up your posts Steven!

                        There are loads more discussions on other threads in different parts of the forum to join in on

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                        • #13
                          Originally posted by fresh dental View Post
                          The first time i get interested in pottery is when i meet my husband, because he told me that his mother did pottery. So when we get married i often visit my inlaws house and i saw different color of bowl and i love it so i get interested in pottery. I haven't started yet, but reading replies, i got some ideas how it works. Thank you
                          Oh ya, come on, so, you are a pet of you inlaws, that is really good news, It is hard to check out such a relationship... lols, However, me too really love poetry, specially the ancient ones, I am collecting those....
                          Malcom,
                          Phonics

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