Need Pictures Of Kiln With Pottery Fired Too Hot In It

[Pugaboo]

Yes I know a weird thing to ask for. I need a picture or pictures of what happens to a kiln when a clay body is overfired in a kiln.

 

I'm trying convince the powers that be that firing work made elsewhere, with unknown clay and glazes is something we don't want to do. That the risk of something going wrong if the person doesn't understand what happens to overfired clay in a kiln isn't worth risking our kilns over. A $10 shelf fee to fire these pieces just doesn't offset the danger to our equipment.

 

I called around and nobody around here will fire work unless it's made on their premises. I called some places in other states, most won't do it either but a couple do with some kind of weird cubic inch formula that sounded like more trouble than it's worth.

 

I want our policy to be if you want your pieces fired in our kilns you have to buy your clay from us.

 

The price of the clay includes a bisque and glaze firing. It seems to me if you know you are making something and you don't have a kiln then you can get your clay here to get it fired. If you are making something too large to fit in your own kiln then plan ahead and buy the clay from us. I realize they can still say it's made with clay from us and have it be from somewhere else but I just don't know how else to state it.

 

In my own kilns I won't fire something made outside of class by a student. I have no way of knowing what was used and I can't afford to lose a kiln or have one out of commission for any period of time. I've had too many people answer when asked....

 

Question: what kind of clay is it?

Answer: "it's white clay"

Question: what cone is it?

Answer: "what's a cone?"

Question: what temperature does it fire to?

Answer: "I don't know my teacher put it in the kiln"

Question: where did you get the clay?

Answer: "at the art store"

Or worse: "somebody gave it to me"

If answered at the art store do you have the receipt?

No I didn't keep it.

....

Sigh and on and on and on

 

I also know a lot are completely confused as to the difference between cone 06 and cone 6. In the past someone bought some pretty glazes and used them. When the kiln was opened it was realized they bought cone 06 NOT cone 6 glazes. When asked why they did that the answer was I thought it meant the same thing, it has a 6 in it! Grrrrrr

 

So I am looking for pictures to prove my point as to why we don't want to fire work made elsewhere with mystery clay and glazes. Nothing like seeing it to get a point across.

 

T

[Dick White]

We have several examples we keep on the shelf in the school studio and bring them out at the beginning of each semester so the new students can see why we hammer them so hard about the concept of "cones" (both as a measure of heatwork and as a commercial product identifier). I won't be back there until Wed. but I'll take some pics then if nobody else has any.

[Guest JBaymore]

Can't find a bigger picture file of this one.  Sorry.  This image was part of some written documentation work I did when I did some consulting for a ceramics cooperative type place that I did kiln work for.

 

It shows the bagwall and floor of a cone 10 firing in a gas kiln when some low fire white clay got mistaken for porcelain clay.

 

 

best,

 

......................john

[neilestrick]

I've seen a number of kilns damaged when low fire work was fired to cone 5/6. It can not only melt the pots all over the shelves, if you've got a full kiln it will ooze into the bricks and elements. I've seen a few kilns that had to be thrown out because it was so bad.

 

In my studio the rule is that I only fire clay brought from me, and that I only fire for my students. I don't want to be in the business of firing. If someone wants to be an independent artist and make work at home then they need to have their own kiln. If not, then they need to be part of a studio.

 

Firing work for 'outsiders' puts way too much liability on you. Even if the piece doesn't melt, folks will complain if their glaze doesn't come out the way they think it should, or if the piece cracks, etc. You'll get the blame and your business may suffer from it. It's just not worth the effort. The only time I will fire for someone that's not a student of mine is after I interview them and figure out their experience level. If they've got a degree in ceramics, then I'll consider it. Anything less and I say no.

[Callie Beller Diesel]

Search Instagram for the account @ceramic_casualties. Every cringeworthy mistake that can be made or photographed has been submitted there. I believe there was a shelf meltdown incident in recent months.

 

Edit: just checked it: there are at least 3 spectacular earthenware-meets-cone-10 disaster shots, including one multiple-level travesty made of some greenish glassy lookin' stuff that was a low fire white clay at one point. Very illustrative if you need ammo to bring to the powers that be.

[High Bridge Pottery]

This is more the glaze side.

 

[GiselleNo5]

Pugaboo, I just had almost exactly that conversation with my nephew. Had no idea what clay it was, what cone it fired to, nothing. I explained to him that if it was a low fire clay it could potentially slump in the kiln. His response was, "Oh, that's okay, I'll understand if the piece doesn't make it." I had to explain very carefully that it was not just HIS piece that might be ruined but other pieces nearby and potentially damage to the kiln too. 

He think's it's a Cone 5 clay but I'm not going past earthenware with it. In his class they fired to 05 so I think that's pretty safe. Worst case, it IS a Cone 5 clay and it gets underfired. 

[Roberta12]

Terry, I would probably have enough money to buy another kiln if I put a dollar in a jar every single time someone asked me to fire something for them.  I loved your "call and response"   Yep, I have heard all of those.  Here' another one.  "my daughter made a bowl in high school and never fired it, can you do that?"  Which high school I asked.  "One in Nebraska".  (I live in Colorado)    I have not had a problem saying no.  It was my $$ that bought the kiln, fires the kiln, bought the furniture, maintains the kiln....so I get to say what goes in it.  Geez, I sound like the little red hen!  Print out some pictures and stand tall!  

 

Roberta

[Marcia Selsor]

I agree. I think we've al been asked more than once. I say No, I don't fire others' work in my kilns unless I supplied the clay. Mistakes are too expensive.

Marcia

[Chilly]

A $10 shelf fee to fire these pieces just doesn't offset the danger to our equipment.

 

I called around and nobody around here will fire work unless it's made on their premises. I called some places in other states, most won't do it either but a couple do with some kind of weird cubic inch formula that sounded like more trouble than it's worth.

 

T

 

The (refundable if everything is OK) deposit has to be high enough to replace the shelf, and all other pots if there is a failure.  That should be enough to put people off.  It's a ruse I use when asked to make something for a persistent asker.  Make the price out of their reach and they go away.

[Pres]

I had this argument several times with students, and with parents that wanted me to fire something that had been made at home for grade. If the clay was not from the school, or the glazes, no deal. Only one time did I fire pots that were not from our school. I was given a bunch of pots made by a deceased student's mother. She asked if I could do anything with them. They had only been bisquefired. I suspected, correctly so, that they were high fire(^9 or above). However, I called the school asked about particulars, and classes the student had taken in the way of Ceramics. I explained the entire story. A week later, I got an email from the school from his professor, and the clay used at that time in his classes-^10 stoneware. We glaze fired them at ^6 in the adult classes that I was teaching on Saturdays. ONLY time I broke a rule, but in the long run, worth it.

 

 

best,

Pres

[Guest JBaymore]

At my college....... we only fire stuff made with the school's clay supply in the gas and electric kilns at our Manchester campus. 

 

The one place it gets "tricky" is the Community Education sign-ups for the college's anagama firing at our Sharon campus (these 'open enrollment' ones happen twice a year).  Because people bring bisque work to the firing (they are responsible to help prep wood, load, fire, unstack, and clean up the kiln also) ...... we have a "lack of control there".  I am the "kiln master" for almost all of the firings... so I am dealing with smaking sure that "questionable" stuff does not get in there....whether that is glaze applications or clay bodies.  We spend a bunch of time communicating with the participants about what is acceptable.  MOST of the participants have decent background in clay....so not usually any questions.  SO far......... no meltdowns or disasters. 

 

(Should not have said that.... we load this Friday, Saturday, and Sunday.)

 

In my kilns at my studio....... I don't fire anybody else's work 99.99999% of the time.  (Except my apprentices work... when I have one.)  VERY occasionally I will specifically INVITE someone to get work in my noborigama.

 

Like the others commenting.... have heard tons of horror stories and seen the results of them over the years.  It is simply NOT worth the risks.

 

If I were doing it in the typical 7 cubic foot electric kiln... the "deposit" would be $3500.00.....fully refundable if the kiln, shelves, and other people's work was still intact after the firing. 

 

best,

 

......................john

[Mark C.]

I have a few stories but to cut this short-you have to say no.Thats the only way to prevent a disaster period.

[Mark C.]

I have only fired my own clay in the past 40 years with three exceptions. One was a animal sculpture and the guy spent 3 months making it -I only bisque fired it so no worries that was in the 80's-it all turned out fine.

The other was a friends father was a sculpture artist and he knew his clays-he never used the ones I suggested and always had issues (cone 10 b-mix) but I just fired them and he had to fix them as they cracked and warped.

The guy who used to be a potter also a good friend had a slumped glass business in the 90's-he wanted me to high fire a lot of stars that are used between the glass stacked in the annealing process. He was once a full time potter-he said the clay was cone 10-it was not-the grinder was a needed and some of my work was toast . That was the last time I EVER will fire clay that did not come from me. I do not fire any work from outside my studio-never-not for any reason . 

You can learn this the easy way and say no or the hard way and say yes. No money will be worth the disaster so charging a fee is not anyway to approach this.

[Pugaboo]

Thank you everyone I am so glad I'm not the only one that thinks it's... well... plain stupid.... to allow unknown stuff to be fired in our kilns. I have saved a few photos and will follow the link to try and get a couple more. I will take the most graphic of the bunch and print it up and show the powers that be and then hang it in the kiln room and just point to it when I say no to firing mystery pieces.

 

Thank you all again you are amazing!

 

T

[perkolator]

I used to have a really good one from our studio but can't find it anymore.  It was from a project we did once where we got a whole bunch of "unsellable" dishes from a thrift store and re-glazed them with underglazes.  I think one of them was actually not clay and may have been glass -- oops

 

Anyways, I would personally fire it - I would just make sure it goes on either a waste shelf or inside a pre-fired firing tray/saggar to catch any mishaps.

 

Here's a few good ones I found on Google images:

 

 

 

 

[tinbucket]

Here's one: earthenware fired to cone ~7

[Joseph Fireborn]

That one of the kiln floor makes me cringe@!!

[oldlady]

 EXACTLY WHY you should put a shelf an inch or so above the bottom!