Goofed My First Bisque Firing

[FredW]

I've just finished my first ever bisque firing (being a beginner and hobbyist) with my home kiln, and realized that maybe I shouldn't have fired it to cone 6—that number stuck in my head because the clay bodies used were rated thusly.

 

So, should I bother trying to glaze the pieces, or just chalk it up as a lesson learned? My concern would be that since the pieces are now vitreous or "matured" that all or most of the glaze will just run off, getting past the shelf edge and onto the kiln floor—which will have an application of kiln wash, but still, I don’t want to risk it.

 

 

Clay bodies used were High Water Clay's Little Loafer's, and Speckled Brownstone.

 

 

Regards,

FW

[Guest HerbNorris]

You might have some success; see this little tip from Lucille, it might help you figure out if your pots will accept glaze :

 

http://ceramicartsdaily.org/community/index.php?/topic/1043-what-does-properly-matured-04-bisque-mean/page__fromsearch__1

[FredW]

Thanks for the lead. Water drop test tells me it's a no-go. No absorption.

[Chris Campbell]

Porcelain artists often high fire first to maturity then glaze fire down low at Cone 04. It's a pain but it can be done on NON functional wares.

Warm the pots in your oven first and glaze quickly ... Do not let it get too thick ... The glaze will dry quickly and stick.

I've never had the glaze run off during firing but you could always fire on stilts if you are concerned.

[Lucille Oka]

I've just finished my first ever bisque firing (being a beginner and hobbyist) with my home kiln, and realized that maybe I shouldn't have fired it to cone 6—that number stuck in my head because the clay bodies used were rated thusly.

 

So, should I bother trying to glaze the pieces, or just chalk it up as a lesson learned? My concern would be that since the pieces are now vitreous or "matured" that all or most of the glaze will just run off, getting past the shelf edge and onto the kiln floor—which will have an application of kiln wash, but still, I don’t want to risk it.

 

 

Clay bodies used were High Water Clay's Little Loafer's, and Speckled Brownstone.

 

 

Regards,

FW

 

 

Don't be nervous. Potters are always testing to find out what works and what doesn't work. If you don't want to test yet maybe one day you may try it. In the mean time keep the pieces covered with plastic to avoid dust accumulating on them.

There are a few things to do before you proceed with another firing. I do not know if your kiln was purchased new or used but get a copy of the manufacturers’ kiln operation manual.

-Read the kiln manual cover to cover. Plan to use the manufacturer’s firing schedule.

 

-Check the recommended bisque temperature of your clay ask your supplier or go online.

 

-If you have chosen commercial glazes read the jar labels.

 

-Make a firing log. Use the log as a guide to what you will be doing, what you have done successfully and what has not worked.

 

Also it maybe a good idea not to deviate from the operation manual’s suggested firing schedule until you get more familiar with firing your kiln.

[Marcia Selsor]

SOme glazes will stick. See if any of yours will.

The problem of the glaze running off the pot would occur when raw. Just sponge it clean before you fire.

You would be lucky to get an excess onto the overtired piece for it to run.

Marcia

[FredW]

Down the road I might give it a try to see what sticks. I'll warm the pieces first, per Chris' post above, and in the meantime I'll bag 'em as Lucille suggested. Out of curiosity, after warming the pieces, should I sponge dampen the surface with water prior to applying the glaze?

[Chris Campbell]

No, that would cool them down and defeat the purpose.

Wipe them down before you warm them.

[Bobg]

I've done that before. What I did was remove some of the water from my glaze to make it thicker. Glazed and fired. It came out the same as when I bisque fire at the right temp at ^6. My brother said he's done the same and he's been potting for 30 years.

[Marcia Selsor]

Down the road I might give it a try to see what sticks. I'll warm the pieces first, per Chris' post above, and in the meantime I'll bag 'em as Lucille suggested. Out of curiosity, after warming the pieces, should I sponge dampen the surface with water prior to applying the glaze?

 

 

Keep the surface clean but don't wet it. Use your glaze as thick as possible by decanting it.

Glazes with a lot of clay or kaolin seem to stick well.

 

Marcia

[Ben]

Commercial dinner ware is commonly done this way. Fired to maturity, vibrated with abrasives to smooth then heated, spray glazed and fired.

It is an automated system and truly shocking in its efficiency. I have no idea as to the formula of the glaze but wonder if it contains something like cmc gum or other organic "glue" to stick the glaze to the pot. You could try adding cmc or cmc and bentonite to your standard glaze recipe. This would add some adhesive quality to your glaze and make it brushable. test test test

 

it would be an interesting experiment and I'd love to hear your results but if it were me, I'd start over. My 2 cents.

 

Good luck, Ben

[Bobg]

I forgot to mention you can also use hair spray to help the glaze still. Just spray it good, let dry and glaze.

[FredW]

Found someone who said they would try to glaze a couple pieces (one each of the different clay bodies) and fire them in one of the local university's kilns. She wasn't to concerned about them already being fired to maturity. Let y'all know how they turn out.

[macdoodle]

Try heating the pots slowly in the kiln or on a warmer tray should be so hot they require you to use gloves to move them and brush on glaze while hot .

I have refired some items with mixed results. The underglazes seem to work best. Some can possibly be applied without preheating. http://www.bigceramicstore.com/Information/tip67.htm

[Pam S]

I made the same goof of bisque firing to ^6. I heated the pots and glazed. They came out fine. The glaze didn't have quite the same result as when bisqued properly, but it worked. I also reglaze anything I don't like. Reglazing is a pain since you can't wax the bottoms.

[Lucille Oka]

I made the same goof of bisque firing to ^6. I heated the pots and glazed. They came out fine. The glaze didn't have quite the same result as when bisqued properly, but it worked. I also reglaze anything I don't like. Reglazing is a pain since you can't wax the bottoms.

 

 

 

Why can't you rewax the bottoms at least the foot? What happens? I never tried this.

[Pres]

Thanks for the lead. Water drop test tells me it's a no-go. No absorption.

 

 

I have occasionally had this problem with a kiln that was overfired due to miss aligned sections. My most success came from spray glazing the pottery to cut back on the absorption problems. I also warmed the ware up before glazing to help dry the glaze quickly. Hit or miss, but can work especially for a piece that you hate to lose. this was the case with kids-so many hours, no pot was a disaster.

[lcar]

I have to say , for years I felt that refires were just being disapointed by the same piece twice, or three times or more if i kept beating my head against the wall! But, now.... i've been doing some testing with Sodium Silicate after reading an excellent article in the 2011 Buyers Guide to the Ceramic Arts, by Richard A. Eppler with Mimi Obstler on glazes. I have used this article, especially the section on Deflocculants and Glaze fluidity, as a start to some experimenting with Sodium Silicate in my glazes. I have made two batches of glazes this way, especially for application on refires. I am quite pleased with the results so far. I suggest trying it, and test test test before risking an entire kiln load. (I know it's hard, as potters we are so optimistic sometimes, lol)

 

lcar