onefire One firing v two

[Jaynieliz]

Hi, new to these forums but really wanted to get some advice. 

I own my own small ceramic studio, I've been doing my own work all through the pandemic as I've not been able to teach. To try and save time, money I decided to try the one firing technique. 

First few bits of work came out ok. But the past two lots (and it's been a lot of work, a full kiln ) have either exploded or the glaze has just now worked. 

I think I'm being counter productive with my work. I have lots of pieces I can't use and now have to make more to cover orders ! 

Just wanted some thoughts on this process ! Is it worth the time and effort or should I go back to my original bisque and then glaze firing. ? 

Maybe I'm rushing or doing something wrong ? 

It's always been a difficult subject to approach with other potter's in the past.....as it's not regarded as 'good practice' . 

Be nice to hear the for's and against please ?

Thanks in advance .

Jayne 

[Bill Kielb]

If you can make it work it saves time and energy. Generally Once fire schedules are at bisque speeds so exploding pieces seems to indicate pieces that were not dry or sufficiently dried prior. Pieces that did not work out aesthetically  can be a function of the combination of glaze and clay as well as potentially a firing schedule. You did not mention your schedule so just curious if you have something that works for you most of the time?

Most potters I know have worked out which combinations and firing schedule work for them over time to avoid the high defect rate issue. No shame in once firing IMO. Saves time and definitely saves energy.

[neilestrick]

Glazing bisqueware is easier than glazing greenware, simply because the pieces are stronger and far less likely to be broken during the process. There are also a lot of decorating techniques that benefit from or require bisque firing before glazing. My work, for instance, can not be glazed without bisque firing because my pieces are covered with wax during the decorating process. I also work in thin porcelain, and trying to glaze many of my forms without bisque firing would be a train wreck. But if you're just applying glazes and your clay body and forms allow for single firing, then go for it. Not all glazes like to be single fired, though, and some modification may be in order. There are a couple of folks here on the forum that will hopefully chime in and give you more specific info on that, because it's not my area of expertise.

If pieces are exploding, then they were too wet to go into the kiln, or too thick for the speed at which you're firing.

[Jaynieliz]

Thankyou for your advice.......I work with porcelain a lot myself and have found that the glazes just don't cover well with one firing.....I've never had so much stuff explode as I have just lately.....maybe I'm rushing to get things done and they are not dry but I'm thinking that maybe I need to go back to my original way. I've got lots of pots etc that I can't use. 

I'm still getting used to the kiln as I've only ever used a very old kiln and cones to fire the temperature I needed.  And I've just done the best I can with my electric kiln, all trial and error and plenty of reading up. 

I use a lot of different techniques including the wax application and different layers of glaze plus glass melting in some of my designs and I agree that bisque firing is better. 

I think I'm just trying to speed things up and it's become a disastrous decision.

Thankyou again for your advice....it's nice to talk to a fellow potter as I don't know any in the area I have my studio ! 

 

 

 

 

 

 

 

[Jaynieliz]

4 hours ago, neilestrick said:

Glazing bisqueware is easier than glazing greenware, simply because the pieces are stronger and far less likely to be broken during the process. There are also a lot of decorating techniques that benefit from or require bisque firing before glazing. My work, for instance, can not be glazed without bisque firing because my pieces are covered with wax during the decorating process. I also work in thin porcelain, and trying to glaze many of my forms without bisque firing would be a train wreck. But if you're just applying glazes and your clay body and forms allow for single firing, then go for it. Not all glazes like to be single fired, though, and some modification may be in order. There are a couple of folks here on the forum that will hopefully chime in and give you more specific info on that, because it's not my area of expertise.

If pieces are exploding, then they were too wet to go into the kiln, or too thick for the speed at which you're firing.

Thankyou for your advice.......I work with porcelain a lot myself and have found that the glazes just don't cover well with one firing.....I've never had so much stuff explode as I have just lately.....maybe I'm rushing to get things done and they are not dry but I'm thinking that maybe I need to go back to my original way. I've got lots of pots etc that I can't use. 

 

I'm still getting used to the kiln as I've only ever used a very old kiln and cones to fire the temperature I needed. And I've just done the best I can with my electric kiln, all trial and error and plenty of reading up. 

 

I use a lot of different techniques including the wax application and different layers of glaze plus glass melting in some of my designs and I agree that bisque firing is better. 

 

I think I'm just trying to speed things up and it's become a disastrous decision.

 

Thankyou again for your advice....it's nice to talk to a fellow potter as I don't know any in the area I have my studio ! 

 

 

[oldlady]

being one of the single firing potters, i will suggest that for MY work, single piece, no handles, additions or extra thick work, single firing with sprayed on glaze works much better than bisquing and firing a second time.    i make pots to sell and simple pieces do that very easily.   the more i handle a single item, the more it costs me to make.

if you look at my albums you can see what i mean.   i make it, dry it, sponge off rough cut edges, glaze it and fire it using the standard kiln slow glaze on the controller.    no long detailed handling necessary.

hate firing bisque.

[Jaynieliz]

1 hour ago, oldlady said:

being one of the single firing potters, i will suggest that for MY work, single piece, no handles, additions or extra thick work, single firing with sprayed on glaze works much better than bisquing and firing a second time.    i make pots to sell and simple pieces do that very easily.   the more i handle a single item, the more it costs me to make.

if you look at my albums you can see what i mean.   i make it, dry it, sponge off rough cut edges, glaze it and fire it using the standard kiln slow glaze on the controller.    no long detailed handling necessary.

hate firing bisque.

Thankyou......I make lots of ceramic bunting and I've had no problems with them, I make them, clean the edges and flags them by painting them. They e all come out great ,no problems at all.

But my mugs and vases all seem to do the same thing. Either explode or the glaze doesn't stick or runs or it just doesn't work. 

The only reason I've been trying the one firing is time and money......so probably best to do the small pieces once and the larger pieces twice. 

Plus I need to look at different firings. Still learning with that ! 

Thanks for your advice....glad I found this forum

[LeeU]

I do the same as Old Lady--in fact it was she who turned me on to single-fire.  I very rarely bisque anymore-only if a decorative technique requires it or if I'm going into a community kiln or for a  raku fire. You might look up Steven Hill and articles in  Ceramics Monthly archives for more info.

[Piedmont Pottery]

You might want to try adding a long soak at 180 Fahrenheit to the beginning of your firing schedule.  A 10 to 12 hour soak at 180 will take far less energy than two firings.  I add long soaks to my bisque programs when firing student pieces, many of which are nowhere near dry when they go into the kiln, and have had zero explosions.  

[dhPotter]

@Jaynieliz I too single fire. There are 2 times when you can glaze. At leatherhard stage or absolutely bone dry. I glaze at bone dry stage. After the piece is made and it is sitting around to dry I leave them alone for at least 2 weeks past my perception of the piece being dry. I used to get spilt rims on mugs. The clay was not absolutely, beyond a doubt bone dry. Now that I have an extended drying period no more split rims. 

[Jaynieliz]

@dhPotter..  ahhh that makes a lot of sense.. I'm just rushing things to try and get orders/my work done.   I tend to leave them past leather hard but they can't be completely dry...I shall try leaving them longer....thankyou so much for your advice 

[Jaynieliz]

  @LeeU....thankyou I shall definitely look up Steven Hill and I have , I think .....a couple of years back copy ceramics monthly or review....thankyou so much for your advice                  @Piedmont Pottery....I never thought of a soak at the beginning of a firing.....I've had to learn by myself how to use the kiln in the best way I can....but I shall definitely try that and I'm sure some of my old books have that firing technique in...defi something I shall try...... thankyou so much.                   @dhPotter..  ahhh that makes a lot of sense.. I'm just rushing things to try and get orders/my work done.   I tend to leave them past leather hard but they can't be completely dry...I shall try leaving them longer....thankyou so much for your advice 

[Callie Beller Diesel]

There’s also a facebook page that’s dedicated to single firing. Could be worth checking out.