Pinholes - clear glaze cone 6

[Larisa]

Hi everyone, 

does anyone perhaps know why pinholes appear in clear glaze fired to cone 6? I do slow firing with a 15-minute hold at 1220*C.

This specific glaze is suitable for firing from 1000-1260*C (I dip it). 

And I’m sure its not applied to thickly. 

Thank you for your help!

Regards, 

Larisa
 

 

IMG_8783-compressed.pdf IMG_8781-compressed.pdf

[Min]

I would try and drop and hold / soak to try and heal those. There is some trial and error in getting a schedule to work but someone to start would be this one.

BTW, I think you are probably getting hotter than cone 6 with a 15 minute soak at 1220C. Do you use cones to verify?

[Larisa]

Thank you. I have a Nabertherm top60, max temperature reach is 1225*C at one point. 

I never had any problems before with my kiln schedules with Mayco Glazes (so I’m a total beginner, because I’ve never try another schedule)… But now I have a new dip clear glaze (TerraColor) and I need to find another solution. 
Also maybe my kiln cools to quickly with these test mugs, because the kiln is not fully load… 

I’ll try these schedule and refire those mugs. We’ll se what happens. 
 

thank you!

[Min]

6 hours ago, Larisa said:

I’ll try these schedule and refire those mugs. We’ll se what happens

Given these have already been glaze fired once I would put them in the coolest part of your kiln or you could have bloating with the clay and or excessive running with the glaze. I’ld also suggest filling those unsealed blisters or pinholes with a dab of thick glaze before refiriring.