flakes sticking in glaze

[PotteryLodge]

I am new to kiln fired ceramics. I am getting my stock up so I can recreate my etsy shop.

I recently bought a small kiln used. It is about 10 years old.

I have been ruining about half of all the ceramics during the 2nd firing. I keep getting a dark(dark blue or black) colored flakes getting stuck in the glaze and its ruining my pieces.

I am using a low fire clay. I fire the greenware to 2008degrees and then fire the glazed bisque to 1875 degrees. In both firings I am noticing dark colored flakes in the bottom of most of my pieces...as well as on the kiln floor.... I can just blow it off after the first firing because the flakes wont stick to the bisque, however the dark flakes ARE sticking during the 2nd firing of glazed pieces.

I used a damp cloth and gently wiped off the kiln floor to clean off all the dark flakes but more flakes keep appearing still.

Any thoughts please

[Former_Member]

Casi, It sounds like your metal thermocouples are flaking and the bits are falling in the bottom of your kiln. I find the same 'stuff' in my kiln after each firing. I brush the thermocouple to remove any loose metal flakes and vac the kiln before each firing.

Catherine

[BeachwoodStreet]

I have had about 8 kilns, some old clunkers- some newish. Are you using an electric kiln with elements? Also are you using a cone with a kiln sitter? I have never had this problem with any of my kilns - however I did once have my husbad grind some metal car part near my clear glazed peices and that was an intresting mess. I do agree that what you are seeing sounds like metal flakes from some place. I now use an new kiln with a digital touch pad and no cone - worth every penny. I would suggest trying to move peices closer to the center and keep your shelves closer. I am curious to know how yo make out! Pleas update me!

[PotteryLodge]

Im using an old electric skutt kiln. I found out what the problem was...the thermacouple was rusting so I cleaned it off and there was the same black debris all over the cloth I cleaned with. I will just have to clean the thermacouple before and after each firing..