Tuesday, September 21, 2010

How to Remove Glaze ?

Remember I made two vine vases? One was very tall and the other is the vase above. Well I put the same crackle glaze on the tall vase as this shorter vine vase above. The crackle glaze shivered off the other vase during the firing. Luckily I didn't fire this taller one below. So the taller vase is sitting in the cabinet with the glaze on it.

But how do I get the glaze off the tall vase so I can glaze it with another glaze? I can wipe the outside off, but how do I get all the glaze out of the inside? It's 16.5 inches tall and 4 inches wide and too tall and skinny for me to get my hands inside. Wish I was tall and skinny. Ha!

Do I just wash it out and then let it dry real well and then re glaze it? Maybe I'll bring it with me and sneak it into Meredith's kiln, it's cone 10 clay. I could use a cone 10 glaze. Think she'll notice if I put it in her kiln?

Many times I have a question and no one to ask, so I might start a regular post on Tuesdays with a question and call them question Tuesdays. What do you think? I mean what do you think about the vase? Comments are welcome.


  1. I'd wash it off Linda and just leave it for a few days. Better that than trying to hide it with more glaze. Short-cuts never work with pottery!

  2. Sponge-on-a-stick? Bottle brush maybe? Slow and gentle.

  3. Hi Mark, thanks, yes I have to wash it off as this cracklke glaze which is cone 6 definitely doesn't fit this cone 10 clay.

    Hi Brian, thanks, I did get a sponge on a stick, I'll try it. I was just wondering if I could immerse it in water or is that too risky. Or could I fill the inside and wash it out, wait a few days and then wash off the outside? I once washed off some oxide that was too dark and I was surprised at how much I could scrub the bisqued piece without it breaking. We shall see.

  4. Lots of water and a brush then dry well.

  5. I wash with a good spray of a nozzle from the hose and then I like what Brian said- sponge on a stick or bottle brush.
    Then let dry for a day or two.
    If you want it in the kiln..... you need to creep over no later then tomorrow....

  6. Hi Dennis, thanks so much. Sometimes these mistakes take longer than they are worth. I saved this one till I saw how the other one did so I must have known something intuitively; trying to save the taller, nicer one till I was sure, live and learn. I knew it was a risk putting cone 6 glaze on a cone 10 body - all the other glazes did fine, but this crackle is more temperamental.

  7. Hi Meredith, thanks, with a hose, wow, that's brave. I guess I might as well risk it, nothing to loose really, except one vase, much better than a whole kiln load.

    I'll have to creep on over for the next load, maybe I'll bring it with me and let you and Mark glaze it for the next time.

  8. If it's bisqued it should be fine to totally submerse in water and scrub. You'll just need to let it completely dry before re-glazing.

    And if you are firing to ^6 you should use a ^6 glaze -- a ^10 clay body just won't be vitrified -- but most commercial claybodies have a wide firing range.

  9. Hi Judy, thanks, good to know about immersing in water, that's the part I wasn't sure about. I normally wouldn't have used this cone 10 clay with a cone 6 glaze, but this was one 25 pound bag of sculpture clay I got at Bennetts by mistake thinking it was cone 6 sculpure clay and discovered it was cone 10 when I got home after I made some pieces with it. So I decided to fire the few pieces with cone 6 glaze, all turned out except this one with this crackle glaze. I was going to bring the pieces down to St Pete's clay to be fired in their gas kiln but it was such a long drive there and back and then there again to pick up the work I decided the cost wasn't worth it to drive there to fire a few pieces. thanks again.

  10. I'll chime in with the bottle brush/sponge on a stick idea. I like the concept of taking a hose nozzle to it, but we don't get enough water pressure here for that to work.

    Also, if you're going functional, I agree you want your clay & glaze to mature at the same temp.

    What makes me curious is the combo of crazing and shivering. Often they're caused by the opposite conditions. Crazing means the glaze shrinks more than the body (the pot-too-big--for-its-britches syndrome) and shivering happens when the body shrinks away from the glaze.

    I've only seen both in lowfire majolica, when I sponged the leatherhard work too much, bringing soluble salts to the surface that then induced shivering.

  11. Hi Kelly, thanks, I am not sure what the correct term is for what happened to this glaze, but you can see it came off in big sharp but thin pieces, like glass, I used the same glaze on a cone 6 clay and it did fine, so I assume it just didn't fit the cone 10 clay. Since it was a textured vase I had to put quite a bit of glaze on it to get it to cover all the spots, and I poured the glaze on the inside. you can see it bubbled inside there.

    All of the sculptural work was non functional so I wasn't worried about vitrification just wanted to get it glazed. The other pieces I made with this clay I fired in the same load and they came out fine, a large basket and two geometric vases but those had different cone 6 glazes on them.

    Perhaps it crazed and shivered because it was crackle; it would have been nice if it had worked.

  12. As long as it's been bisque fired, I'd soak it in water, then use a bottle brush to scrub out any bits that are left that you can't reach. Even on fairly thin walled work, I've removed glaze with pretty vigorous scrubbing from bisque ware. As long as I let it fully dry before attempting to glaze it again, there were no problems.

  13. Hi Julia, thanks ever so much to you and others, the concensus seems to be I can use quite a bit of water, that's what I was worried about all the water. I'll be scrubbing it down and reglazing it.

  14. Since I don't know much about this subject, I'll just wish you good luck! These sound like some very good suggestions.


I love suggestions, questions, critiques, thanks for your comment