losing to much detail when using underglazes

[EricaJ]

I am a glass artist that has been starting to make tiles...and boy do I need some help! Trial and error and reading have been ok, but this forum looks like it would be more helpful. :-)

I am looking for glazing information-I have been underglazing greenware, having it fired to bisque (04) and the tiles look fantastic. The problem occurs when those tiles get high fired to 6...I lose the detail of the feathers and fur that I painted. (The tiles will be outside, so they need to be fired to cone 6.)

Any thoughts on this subject?

Thank you for your time.

[Andy Clift]

Hi Erica,
Thanks for joining. I am going to move this message to a more appropriate forum so it will get more responses.

Also, I do have a couple of questions because a might be able to give you some advice. Are you using commercial underglazes, if so what brand. What do you mean by losing detail? Does that mean lighter colors are disappearing onto the darker colors underneath, or is it the thickness that is covering up the texture. Also what color is your clay body.

[EricaJ]

Hi Andy, wonderful site-glad I found it, and thank you for your time. To answer-I am using Duncan Concepts underglazes and the clay body is white. I lose detail when the piece is high fired, (the fine detail I paint to render feathers fades and is not nice crisp lines like when it's bisque fired.)

1st photo: underglazed greenware that was bisque fired to 04, then more detail was added before re-firing to 6
2nd photo: bisque fired piece that was high fired to 6

[Andy Clift]

Is it the white that fades? If so you might want to use a sgraffito technique since your using a white clay body.

Here is a video with more about sgraffito.

[lakesidepottery]

Hi Erica,

We spend months testing all the available underglazes with several clear glazes and determined that only one clear glaze has the least impact on coloring but most underglazes were rejected even with this best clear glaze. We ended up with a mix and match of manufacturers but managed to get full compliment of colors that work at cone 6. See link below for the details of what underglazes worked for us with what clear glaze.

Cone 6 Glaze Recipes | Great Mid Range Pottery Glazes | Oxidation

Kindly, Patty and Morty