Help! I Forgot To Bisque Before Glazing.

[TheSamm 0]

So, I've been working on two slab projects for the last 2 weeks. Both of them have some pieces in the 3rd dimension as well as lots of 2D detail. I finished constructing both pieces today and despite how shaky my hands were, managed to paint both almost immaculately. Thing is, I forgot to give them a bisque firing before I jumped into glazing them. They're so detailed that there's no way I can remove the glaze without destroying the work in the process, so unless there's another way to make finished work out of them, they're garbage and I wasted my time, materials, and effort.

 

My instructor must have felt really bad for me, because as I was sticking the pieces back on the rack and deciding whether or not to trash them she came over and decided my stuff was special enough that we were going to try a risky operation, putting both pieces through both bisque firing and final firing despite them being glazed out of order. She says that the color won't be as consistent and you couldn't eat off of them (fine by me, because they're not dishes), but they should still stick together and come out okay.

 

Before we try this, however, I wanted to take some initiative and research both the risks of this test and any alternatives. Despite my excellent googling skills, I haven't been able to find an article or forum topic specific enough to my situation, so I figured I'd start one myself. Any and all information you can give me will be useful. I just want to know what might happen if we try to fire this thing and/or if there are any other ways to save the work with less risk involved.

[GEP 1,664]

There are lots of glazes that can withstand being applied to greenware, then go through a bisque firing and a glaze firing. And there are some that won't make it. The fit just won't match and the glaze will flake off during the bisque. I once did this with my students on purpose. The ones that worked the best had a thin application of glaze. The thicker the glaze, the more likely it was to flake off during the bisque fire. 

[smastca 3]

Excuse the beginner question - but why can't you just single fire?  Just do the glaze firing and skip the bisque.

[oldlady 2,237]

what do you worry about most?  single firing is not that unusual.  i fire that way all the time but i do uniform thickness to my  work and know what to expect when i do it.  firing pieces that are raw and pieces that are bisqued and refiring finished glazed pieces at the same time does not cause problems either.   the speed at which you go up to about 1200 degrees probably means more than anything else.  i know the temp where most people consider conversion is about 900 but i am talking about an entire kiln load steaming away the water vapor.  it takes time and 1200 is my safety number.

Edited April 6, 2018 by oldlady
clarity

[bciskepottery 959]

Single fire is an option . . . but you will need to glaze fire slowly.  Firing twice seems twice as risky. 

[Bob Coyle 114]

I can't see you have many good alternatives. You can't take the gaze off and start over, so you might as well give it a try.

[GEP 1,664]

If this is a classroom situation, the glaze firing is probably not programmed to go up to bisque temp slowly enough for a green pot. It does not make sense for them to program a kiln for a once-firing that only contains two pieces. OP should put the pieces into a bisque firing first, then a glaze firing.

 

If the glazes flake off or do anything weird in the bisque firing, you can touch up your pieces with glaze before they go in the glaze firing.

[LittleGreenPot 1]

hello, I was going to start a thread on this, I have two members of a class who glazed all their work on greenware. My fault for not seeing it before they had spent ages doing it. So removing it is not an option? Shall I try and glaze fire it? Thanks 

[curt 257]

What GEP said

[oldlady 2,237]

the discussion of why and what will make your students remember this experience for life.  a good teaching moment.