[macdoodle]

" ok- so I just got off the phone with my pottery teacher at the museum. He said it sounds like the sculpting clay is stoneware and I thought it was earthenware the whole time. Obviously It is still over fired, so I am going to see if the glaze sticks to it before i attempt to fire it. Luckily for me, the museum is going to cancel art classes and might be willing to sell me some proper clay! That would be a major break! At least i made a good mistake, if it had been earthenware my kiln would likely be a huge mess. "
[/quote]

If the glaze won't stick via dipping - try heating each piece on a hot plate and then painting the glazes on with a brush.

Also Beware of clay that says cone 5-10 that is too wide a range to be accurate. See if you can call and find out where it really vitrifies if you intend to use it for functional pieces.

This chart may help get you more familiar with firing ranges-

• [PDF]
  Firing Temperatures - Bellevue College
  bellevuecollege.edu/artshum/materials/art/.../FiringTemperatures.pdfFile Format: PDF/Adobe Acrobat - Quick View

[Mark C.]

My advice is you must know your clay body-what it is and what its to be fire to if not-chuck the clay in the trash
Ceramics is all about knowledge
Second if you have fired that work to cone 4 toss it out-as it is too much work to try to get glaze to stick
Make new work out of a clay you know-this helps in two ways first you need throwing experience and second you will now know what to fire the clay to temp wise.
Third it will bring you less grief-
Mark

[TJR]

Dear Reddy;
The reason everyone is freaking out here is the first sentence in your blog."Just finished bisquing at Cone 4"
This was the red flag. You have mixed up Cone 4 with cone 04. Cone 04 is low, cone 4 is several hundred degrees hotter.
Here are a couple points in order to help you.
First of all, it's OK to be a newbie. We all started somewhere. You just want to make sure you are getting the best advice you can.
1. Do not buy clay from an Art Supply store. Buy it from a Ceramic Supply store. See if you can get together with a couple of people to share the cost. A 50pound box of EARTHENWARE clay should cost you $18.00
2. Like mark said, get a hammer and smash those pots. They are never going to accept a glaze. They are too vitrified.[look it up]
3. When bisquing, bisque low and glaze high. I bisque at Cone 06,or even 07 which is lower still.
4.I glaze my earthenware at Cone 04, or 03, which is hotter by one cone.
5. Think of the cones like negative numbers moving from cooler to hotter. They go like this;07,06,05,04,03,02,01,1,2,3,4,5,6,7,8,9,10,11,12.
You can see that you were 8 cones hotter at least than you should have been. This is why people are freaking out.
If you were flying a plane and the pilot had a heart attack, I would be the guy to call to talk you down.
Enjoy your ceramic experience, and please don't melt your kiln
Tom Roberts[TJR]

[rebbylicious]

TJR, on 02 January 2013 - 01:25 PM, said:

Dear Reddy;
The reason everyone is freaking out here is the first sentence in your blog."Just finished bisquing at Cone 4"
This was the red flag. You have mixed up Cone 4 with cone 04. Cone 04 is low, cone 4 is several hundred degrees hotter.
Here are a couple points in order to help you.
First of all, it's OK to be a newbie. We all started somewhere. You just want to make sure you are getting the best advice you can.
1. Do not buy clay from an Art Supply store. Buy it from a Ceramic Supply store. See if you can get together with a couple of people to share the cost. A 50pound box of EARTHENWARE clay should cost you $18.00
2. Like mark said, get a hammer and smash those pots. They are never going to accept a glaze. They are too vitrified.[look it up]
3. When bisquing, bisque low and glaze high. I bisque at Cone 06,or even 07 which is lower still.
4.I glaze my earthenware at Cone 04, or 03, which is hotter by one cone.
5. Think of the cones like negative numbers moving from cooler to hotter. They go like this;07,06,05,04,03,02,01,1,2,3,4,5,6,7,8,9,10,11,12.
You can see that you were 8 cones hotter at least than you should have been. This is why people are freaking out.
If you were flying a plane and the pilot had a heart attack, I would be the guy to call to talk you down.
Enjoy your ceramic experience, and please don't melt your kiln
Tom Roberts[TJR]

Thanks!! I knew the difference between 04 and 4, but having never fired before, I was shocked to see my notes say "4" because i know 04 is much lower. But I decided to be an airhead and stick with my notes rather than go with my gut. THe glaze is sticking good, but I am nervous to bake it, so I might just break all the work i did this summer. . The problem with clay is not the cost, its the shipping. Shipping is $60 from paoli clay which is a few hrs north from where I live. I found a shop that is an hr away from here that I can drive and buy it by the 50# or higher box. My kiln will take up to 2300 degrees (which is cone 9 right?) I want to experiment with both high fire and low fire clay bodies because I like the intricate design options with earthenware, but the durability of stoneware. I want to be able to make cups and pie plates etc that I am able to use. But as you said 5-10 is a huge range. I am planning to get some wheel throwing clay.

Are you all suggesting that I don't bake the glaze on?

[rebbylicious]

2 more things-

I literally was LMAO when you refered to me as "reddy" rather than "rebby"... it seems I bit off more than I could chew, and eager "reddy" is a fitting name! LOLOLOL!! No wonder everyone is freaking out... "reddy just fired bisque at cone 4" lmao

Anyways, I am planning to drive over to Sturtevant wi to A. R. T. for some clay. Does anyone have a suggestion on which HF and LF I should use as a beginner? I don't like the look of the super red terra cotta or dark stuff. I prefer it to be light gray or pink.

[OffCenter]

rebbylicious, on 02 January 2013 - 03:04 PM, said:

TJR, on 02 January 2013 - 01:25 PM, said:

Dear Reddy;
The reason everyone is freaking out here is the first sentence in your blog."Just finished bisquing at Cone 4"
This was the red flag. You have mixed up Cone 4 with cone 04. Cone 04 is low, cone 4 is several hundred degrees hotter.
Here are a couple points in order to help you.
First of all, it's OK to be a newbie. We all started somewhere. You just want to make sure you are getting the best advice you can.
1. Do not buy clay from an Art Supply store. Buy it from a Ceramic Supply store. See if you can get together with a couple of people to share the cost. A 50pound box of EARTHENWARE clay should cost you $18.00
2. Like mark said, get a hammer and smash those pots. They are never going to accept a glaze. They are too vitrified.[look it up]
3. When bisquing, bisque low and glaze high. I bisque at Cone 06,or even 07 which is lower still.
4.I glaze my earthenware at Cone 04, or 03, which is hotter by one cone.
5. Think of the cones like negative numbers moving from cooler to hotter. They go like this;07,06,05,04,03,02,01,1,2,3,4,5,6,7,8,9,10,11,12.
You can see that you were 8 cones hotter at least than you should have been. This is why people are freaking out.
If you were flying a plane and the pilot had a heart attack, I would be the guy to call to talk you down.
Enjoy your ceramic experience, and please don't melt your kiln
Tom Roberts[TJR]

Thanks!! I knew the difference between 04 and 4, but having never fired before, I was shocked to see my notes say "4" because i know 04 is much lower. But I decided to be an airhead and stick with my notes rather than go with my gut. THe glaze is sticking good, but I am nervous to bake it, so I might just break all the work i did this summer. . The problem with clay is not the cost, its the shipping. Shipping is $60 from paoli clay which is a few hrs north from where I live. I found a shop that is an hr away from here that I can drive and buy it by the 50# or higher box. My kiln will take up to 2300 degrees (which is cone 9 right?) I want to experiment with both high fire and low fire clay bodies because I like the intricate design options with earthenware, but the durability of stoneware. I want to be able to make cups and pie plates etc that I am able to use. But as you said 5-10 is a huge range. I am planning to get some wheel throwing clay.

Are you all suggesting that I don't bake the glaze on?

Rebbylicious, It's really neat that you're so excited about potting and TJR's advise above is great (The 04-4 thing didn't freak me out as much as your attitude that was sorta like somebody saying "I'm not very good with a rifle so I'm just going to grab this stinger missile here and go hunting.") but I'd like to make a suggestion or three. Firing to cone 10 may be a bit much for a kiln as old as yours. Consider cone 6 for your high fire clay. When fired to maturity it is just as strong or stronger than any cone 10 clay and it is High Fire and your kiln is much more likely to get to cone 6 than it is to cone 9 or 10. Plus you save time, electricity and your kiln. (BTW cones measure heat work--time and temp--not just temp. So 2300 degree F could be just about any cone between 7 and 11 depending on how fast the kiln is fired.) I assume you don't want your cups and pie plates to leak so firing the clay to full (not just approximate) maturity is important (and for pie plates you want a clay that can take some thermal shock, but that's a whole new can of worms). You shouldn't depend on a glaze stopping an under fired clay from leaking because in most cases it will not. Just because earthenware isn't high fire doesn't mean it isn't strong. We've gone over and over this on this forum. A highly respected teacher and potter (Pete Pinnell) did test that showed the earthenware he and his classes tested was stronger than any of the porcelains and stonewares tested. Regardless of how accurate those test were, the important thing is that clay be fired to maturity, not how high it is fired. Last and certainly least, just to keep some of us from convulsing don't use the word "bake" when talking about firing pottery.

Jim

[neilestrick]

In low fire clay bodies you're generally only going to get white or terra cotta. Even though your kiln can go to cone 9, it's not necessary to ever fire it that hot. Stick with cone 5 or 6 if you want to make vitrified functional pots. Unfortunately, A.R.T. has a poor selection of cone 5/6 bodies. I'd go with Brownstone I #107 or the Buff #103. Do not use those that say cone 5-10. They won't be tight enough at cone 5/6.

[TJR]

OffCenter, on 02 January 2013 - 04:57 PM, said:

rebbylicious, on 02 January 2013 - 03:04 PM, said:

TJR, on 02 January 2013 - 01:25 PM, said:

Dear Reddy;
The reason everyone is freaking out here is the first sentence in your blog."Just finished bisquing at Cone 4"
This was the red flag. You have mixed up Cone 4 with cone 04. Cone 04 is low, cone 4 is several hundred degrees hotter.
Here are a couple points in order to help you.
First of all, it's OK to be a newbie. We all started somewhere. You just want to make sure you are getting the best advice you can.
1. Do not buy clay from an Art Supply store. Buy it from a Ceramic Supply store. See if you can get together with a couple of people to share the cost. A 50pound box of EARTHENWARE clay should cost you $18.00
2. Like mark said, get a hammer and smash those pots. They are never going to accept a glaze. They are too vitrified.[look it up]
3. When bisquing, bisque low and glaze high. I bisque at Cone 06,or even 07 which is lower still.
4.I glaze my earthenware at Cone 04, or 03, which is hotter by one cone.
5. Think of the cones like negative numbers moving from cooler to hotter. They go like this;07,06,05,04,03,02,01,1,2,3,4,5,6,7,8,9,10,11,12.
You can see that you were 8 cones hotter at least than you should have been. This is why people are freaking out.
If you were flying a plane and the pilot had a heart attack, I would be the guy to call to talk you down.
Enjoy your ceramic experience, and please don't melt your kiln
Tom Roberts[TJR]

Thanks!! I knew the difference between 04 and 4, but having never fired before, I was shocked to see my notes say "4" because i know 04 is much lower. But I decided to be an airhead and stick with my notes rather than go with my gut. THe glaze is sticking good, but I am nervous to bake it, so I might just break all the work i did this summer. . The problem with clay is not the cost, its the shipping. Shipping is $60 from paoli clay which is a few hrs north from where I live. I found a shop that is an hr away from here that I can drive and buy it by the 50# or higher box. My kiln will take up to 2300 degrees (which is cone 9 right?) I want to experiment with both high fire and low fire clay bodies because I like the intricate design options with earthenware, but the durability of stoneware. I want to be able to make cups and pie plates etc that I am able to use. But as you said 5-10 is a huge range. I am planning to get some wheel throwing clay.

Are you all suggesting that I don't bake the glaze on?

Rebbylicious, It's really neat that you're so excited about potting and TJR's advise above is great (The 04-4 thing didn't freak me out as much as your attitude that was sorta like somebody saying "I'm not very good with a rifle so I'm just going to grab this stinger missile here and go hunting.") but I'd like to make a suggestion or three. Firing to cone 10 may be a bit much for a kiln as old as yours. Consider cone 6 for your high fire clay. When fired to maturity it is just as strong or stronger than any cone 10 clay and it is High Fire and your kiln is much more likely to get to cone 6 than it is to cone 9 or 10. Plus you save time, electricity and your kiln. (BTW cones measure heat work--time and temp--not just temp. So 2300 degree F could be just about any cone between 7 and 11 depending on how fast the kiln is fired.) I assume you don't want your cups and pie plates to leak so firing the clay to full (not just approximate) maturity is important (and for pie plates you want a clay that can take some thermal shock, but that's a whole new can of worms). You shouldn't depend on a glaze stopping an under fired clay from leaking because in most cases it will not. Just because earthenware isn't high fire doesn't mean it isn't strong. We've gone over and over this on this forum. A highly respected teacher and potter (Pete Pinnell) did test that showed the earthenware he and his classes tested was stronger than any of the porcelains and stonewares tested. Regardless of how accurate those test were, the important thing is that clay be fired to maturity, not how high it is fired. Last and certainly least, just to keep some of us from convulsing don't use the word "bake" when talking about firing pottery.

Jim

Jim, The term was "cookin". Great analogy by the way,wwith the dangerous missiles. I am usually pretty good with analogies, but drew a blank on this one?
Reddyliciou, I apologize for getting your name wrong. Congratulations on stirring up a great blog.
Tom

[bciskepottery]

Perhaps lost/overlooked in the cacaphony of advice . . . those are some nice looking pots in your picture. As the clay is cone 5 to 10, and you fired to cone 4, they might not be as vitrified as you think. Pick one out, glaze it, and give it a test fire. Maybe put an iron oxide wash on the outside and glaze on the inside. Never hurts to try. It's how we all learned this stuff.

[rebbylicious]

bciskepottery, on 02 January 2013 - 06:36 PM, said:

Pick one out, glaze it, and give it a test fire. Maybe put an iron oxide wash on the outside and glaze on the inside. Never hurts to try. It's how we all learned this stuff.

Are you sure It isn't part of the whole "missle" analogy if I were to try this? I was told I might kill somebody? I am hesitant to try it out now. Although it is heartbreaking to part with my yarn bowl. .. Perhaps sticking to my crochet is less dangerous?

[bciskepottery]

In an earlier post, you mentioned that glaze was sticking to the pots. Well, if its sticking without any problem, they might be glaze-firing worthy. Maybe check with your insntructor . . . but it sounds to me that the wares are not vitrified and could be glazed. As I mentioned, while you bisqued to cone 4, a clay body with a range of cone 5 to 10 would not vitrify until cone 10.

What cone are your glazes? As Jim and some others advised, given the age of your kiln you might not want to glaze fire above cone 6. Are you brushing on glazes or dipping them?

Before glaze firing, walk through the firing with your instructor or another person who has fired kilns before. That way you can save the stinger missle for bigger and better targets.

Here is a link to a listing of clay suppliers in Wisconsin http://ceramicartsda...carts2013/#/72/ Not sure where you are, but I can admit to knowing of Sturtevant and Belleview.

[rebbylicious]

neilestrick, on 02 January 2013 - 05:28 PM, said:

In low fire clay bodies you're generally only going to get white or terra cotta. Even though your kiln can go to cone 9, it's not necessary to ever fire it that hot. Stick with cone 5 or 6 if you want to make vitrified functional pots. Unfortunately, A.R.T. has a poor selection of cone 5/6 bodies. I'd go with Brownstone I #107 or the Buff #103. Do not use those that say cone 5-10. They won't be tight enough at cone 5/6.

I think that is good advice. I wasn't planning on firing a cone nine, I was just saying that because someone mentioned me melting my kiln at cone 4. (unless they were refering to melting clay on the inside) My kiln is fron 1969 and I want it to last as long as possible. (at least until i figure out the craft enough to spend the money on a new one if it were to die on me)
I do have some pretty glazes for low fire, so I would like to get some low fire ones as well just to play with. Should I do the same and get the white talc for the earthenware? When they say cones 5-6 should /do most people try out the smaller cone first or the higher cone?

[Nancy S.]

Rebby,

I'm not sure what's going to happen with your glazed pieces - definitely do one to test it. What glaze are you using - a commercial glaze, or a homemade one?

Even though the glaze seems to be sticking right now, it may not stick in the final firing. Bisquing to 04 allows the ware to be more porous, and the glaze really "gets into" the pot so that they are enmeshed together rather than just glaze sitting on top of the clay (which may lead to the glaze chipping off later).

What brand of clay is it? You might have better luck in the future with a name brand like Laguna or Standard. I completely understand the whole "shipping is INSANE on clay" lament all too well -- until I found a local distributor of Standard's clay, I feared I'd have to drive to Pittsburgh or Philly to get my clay because that would be cheaper than having it shipped!

Good luck with everything. If the glazing doesn't work out and you don't want to destroy your work, you may be able to paint it (though I don't know if they'll be food-safe; I don't have a lot of experience with that). Let us know what happens!

[nrsmdwf]

I am a newbie over and over and over again in the past 20 years. I experimented with several clays and several glazes. I found I never figured out how to get good results (would have one single decent piece out of the whole kiln load, and couldn't replicate it). Constantly frustrated and disappointed. Closed up the "studio" for years at a time.

My suggestion is to pick ONE clay body you want to work with, and only one or two glazes. Exhaust the possibilities (sizes, thicknesses, glaze application techniques, etc.) with those before you add in another clay or glaze. Make excellent notes in a spiral notebook. Don't assume you will know what you meant 3 or 6 months from now, so take time to write it out well. It takes longer than you want, but at least you will feel like an "expert" in one clay and one glaze. It's really, really hard to stick with this plan, but honestly, it will save you tons of frustration, and you really will be able to sit down and make gifts for people in the clay and glaze you know and understand.

[TJR]

Rebbylicious;
There has been some GREAt advice on here from a lot of experienced people. You say your glaze will stick? Then you need to decide what cone your glaze will be. The cone of the glaze will be marked on the label. If you are thinking cone 6,then you need to go to a ceramics supplier and buy a couple of jars of glaze. You mention shipping cost for clay? A lot of us drive to the supplier and pick it up ourselves. No shipping! I usually buy 6 boxes of clay at a time, That is as much as I can fit in my car.
I say glaze at least one or two pots and see how they look. Keep at it!
TJR.

[rebbylicious]

The highest fire glaze i have says "witness cone 5" It's an amaco sahara clear glaze. I am a bit worried about meltdown and going high with vague clay now....

and I was brushing it on

[Pres]

rebbylicious, on 03 January 2013 - 08:54 AM, said:

The highest fire glaze i have says "witness cone 5" It's an amaco sahara clear glaze. I am a bit worried about meltdown and going high with vague clay now....

Visual inspection of your ware, fired at cone 4, does not indicate that it could not fire to cone 5. You should not have any problems firing these pots to cone 5 or 6. Take your time applying your glaze, and make certain you use the correct cone. Now as to the glaze choice, your transparent glaze will do fine, but an opaque glaze will have a little more color, richness, and hide some small surface marks you may have. You may consider getting some opaque glazes.

In the future, if I may be so bold as to suggest:

1) Decide on the type of ware you wish to create-from present work I would say functional.
2) Choose a clay body from a reputable distributor based on the clay fired color, working characteristics, and firing temperature you wish to fire to. Remembering that the choice of color will have an effect on the glaze colors-white bodies,brighter glazes,mid bodies, softer colors.
3) Order a box of cones for your bisque temp, and your glaze temp based on the clay and glazes you choose.
4) Set up a firing schedule sheet, notating when you start the kiln, how long you watersmoke, when you turn up the switches etc. Be specific, as this will help you become consistent in your firings. You can find recommended schedules on many different sites including clay distributors and kiln company sites.
5) Realize that it is all part of the learning curve, don't get frustrated, keep on plugging. Your pieces have merit, they just need more experience and skill development behind them to meet your expectations.

[rebbylicious]

Pres, on 03 January 2013 - 08:30 AM, said:

rebbylicious, on 03 January 2013 - 08:54 AM, said:

The highest fire glaze i have says "witness cone 5" It's an amaco sahara clear glaze. I am a bit worried about meltdown and going high with vague clay now....

Visual inspection of your ware, fired at cone 4, does not indicate that it could not fire to cone 5. You should not have any problems firing these pots to cone 5 or 6. Take your time applying your glaze, and make certain you use the correct cone. Now as to the glaze choice, your transparent glaze will do fine, but an opaque glaze will have a little more color, richness, and hide some small surface marks you may have. You may consider getting some opaque glazes.

In the future, if I may be so bold as to suggest:

1) Decide on the type of ware you wish to create-from present work I would say functional.
2) Choose a clay body from a reputable distributor based on the clay fired color, working characteristics, and firing temperature you wish to fire to. Remembering that the choice of color will have an effect on the glaze colors-white bodies,brighter glazes,mid bodies, softer colors.
3) Order a box of cones for your bisque temp, and your glaze temp based on the clay and glazes you choose.
4) Set up a firing schedule sheet, notating when you start the kiln, how long you watersmoke, when you turn up the switches etc. Be specific, as this will help you become consistent in your firings. You can find recommended schedules on many different sites including clay distributors and kiln company sites.
5) Realize that it is all part of the learning curve, don't get frustrated, keep on plugging. Your pieces have merit, they just need more experience and skill development behind them to meet your expectations.

<3 thanks!

[rebbylicious]

One of the reasons I like the idea of doing some low fire clays too is that I want to be able to paint on designs to my pots. I want to be able to write words etc. (it's a long story etc, goes along with studies of positive words impacting water molicules etc, etc) I love the color play that stoneware glazes offer, but I need to be able to do detailed designs as well. I am also HIGHLY inspired by polish pottery designs and would love to make "polish design inspired" That is why I was talking about using 2 kinds of clay (not at the same time of course). Is there a happy medium out there?

[OffCenter]

rebbylicious, on 03 January 2013 - 09:54 AM, said:

One of the reasons I like the idea of doing some low fire clays too is that I want to be able to paint on designs to my pots. I want to be able to write words etc. (it's a long story etc, goes along with studies of positive words impacting water molicules etc, etc) I love the color play that stoneware glazes offer, but I need to be able to do detailed designs as well. I am also HIGHLY inspired by polish pottery designs and would love to make "polish design inspired" That is why I was talking about using 2 kinds of clay (not at the same time of course). Is there a happy medium out there?

Less to learn in a short time if you stick to one clay at least for a while. You can paint on designs and write words on cone 6 pots. You won't find a lot of great glaze recipes in it but you will find some good basic glazes and get a good foundation in working with glazes so that your glazes not only fit the clay and work well, they also don't poison you or others. For example, if you're going to write on a pot you could do it by first covering the pot with a white glaze that doesn't move. (Most glazes move at least a little during firing.) A good glaze for that is:

Ron's Cone 6 Maiolica
Nepheline Syenite ... 23
Ferro Frit 3124 ... 23
Whiting ... 14
EPK Kaolin ... 17
Silica ... 23
Zircopax ... 16

I'm guessing that you aren't set up for mixing glazes yet, so you could look for a similar commercial glaze or try to get a good deal on chemicals from that ceramics class that is closing up that you mentioned somewhere in this thread.

Of course, maybe going low fire would be better for you. Google Linda Arbuckle and Posey Bacopoulous to be introduced to the wonderful world of majolica if you aren't already familiar with it.

Jim