Honey Bee On Dusty Miller
by Linda Starr
by Linda Starr
Since January I've been busy as a bee. The bees wings above look a little tattered don't they. My wings feel a bit tattered too and the sad but true story follows. I've been extremely busy for months making new ceramic pieces and experimenting with new textures, designs, slips, and surfaces. Do you think a bee ever gives up? No, probably not, but I have seen bees cleaning out their hives and sometimes they look for a new hive. Well, I have some hive cleaning to do and I'm also looking for a new hive.
Clary Sage Vase
glaze crawled on leaves
glaze crawled on leaves
Can a kiln be fired without cones? Sure, just light the burners and walk away. Oh, wait a minute, there were cones in the last glaze firing, but no one looked at them till the kiln was unloaded. Oops too late.
someone's glaze sputtered over lots of my pieces
I think I'll make angel food cake, put it in a cold oven, and turn the oven to 350. When the oven gets up to 350, I'll turn the oven off and let it cool down. Won't that be a tasty cake? Hey, I like the taste of cake batter. Not quite the same on uncooked pots though. Sorry to be sarcastic, but I just can't help myself.
Slip Decorated Butterflies
unmelted transparent glaze interior of wall pocket
unmelted transparent glaze interior of wall pocket
Every piece in this firing is under fired. The glazes didn't melt completely. Even the transparent glaze on the Victorian Lace pieces isn't completely melted. And there was lots of crawling. I washed off every piece I glazed and I didn't use wax so no contamination there. If you have any thoughts about the crawling, please let me know. Most times when a glaze crawls you can see bare clay, this time there is a reddish pink skin where it crawled?
The only pieces which don't need to be re fired are the pieces I showed you in my Dead Wood post where I used only stains or oxides - my faux bois bark sculptures. All of my pinch pots with blue and green celadon, tenmoku, tea dust and other glazes and slips are pitifully under fired. Remember when I was slip decorating butterflies, I thought the wall pocket was passable, but I looked inside, unmelted and crawled transparent glaze, like drips of snot, ugh. The butterflies look so nice, maybe I can re fire this piece. Same ugly glaze drips in the Clary Sage Vase.
Pinched Bowl
tea dust glaze, rim cracked next day
tea dust glaze, rim cracked next day
In this firing three single cone 10 cones were placed in the kiln, one on the bottom, one in the middle and one on the top shelf. None of the cones bent. So what cone was the kiln fired to? Besides under firing, the glazes of one other person with a lot of work in the kiln spattered all over everything, including many of my pieces. The glazes didn't run they shivered off and shot all over the kiln. Pieces on the bottom shelf got glaze shivering from the top shelf. I even had one pinch pot with some of the shivering glaze in the bottom of the pot, only in the bottom, no where else. None of my other pinch pots came out much better either.
Derriere Pot
not mature celadon glaze
not mature celadon glaze
The person firing the kiln has been making pots for years and was in charge of the firing. He said the kiln reached 1800 F and then he left for five hours. Later when the kiln was checked it was at 560 F. The kiln was brought back up again. Then apparently they could only get the kiln to go up to 2345 according to the pyrometer. They also said they don't think the (old) pyrometer is accurate. Besides all that when bisque loads are fired, no cones are used then either, once when they used cones for the bisque 06 wasn't melted, but there wasn't an 07 cone used so still no way of telling what the bisque was fired to. I suspect all the bisque loads are under fired and then when the pots are put in the glaze load impurities want to burn out through the surface and cause crawling in the glazes. Even the glaze on my cute little Derriere Pot didn't mature.
Crowded City window box
crawled, not mature glaze
crawled, not mature glaze
Remember my Crowded City window box? The hand built piece with 17 separate pieces. It made it through the bisque and the glaze firing, but the green to black satin matt glaze didn't melt completely and there was crawling too. I loaded the Crowded City window box into the kiln myself giving it plenty of room.
Clary Sage Vase (reverse side)
unmelted glaze and piece stuck to front
unmelted glaze and piece stuck to front
Later it was moved and placed touching my Clary Sage Vase. The glazes melted and the two vases stuck together in one small spot. These are both hand built vases that took me several hours each to build. I take full responsibility for the splotches of cobalt on the green side of the vase, it seems as though cobalt wash can't be washed off no matter how hard I scrub. I must be more careful in the future.
As luck would have it, I talked to a potter earlier a couple of weeks ago who works with crystal glazes. He told me about his technique for getting runny glazes off the kiln shelf without breaking his pots. He uses a torch to heat the glazes if they stick. I thought this technique might work for the two vases which stuck together. I used a jewelers torch to melt the glazes where touched and they came apart. The Clary Sage Vase has a tiny piece of glaze left from the window box vase which I need to heat up and try to remove.
Pinched Tea Bowl
crawled tea dust glaze
crawled tea dust glaze
One hand built vase seemed to be OK - my Ben Vase which I glazed with ohata kaki. This was the vase I textured with wire, nuts, and bolts. It actually looked perfect. Then the next day I looked at it and it started to develop cracks starting on the side perpendicular to the seam. The cracks weren't there previously. I didn't drop the vase or knock it against something. I've heard pinging noises coming from the vase. I suspect the glaze is mature, but the clay body is not and the glaze is contracting against the clay body and putting pressure on it causing it to crack.
Ben Vase
looks OK from a distance
looks OK from a distance
cracks forming perpendicular to side seam
They are going to squeeze in one more glaze firing and I'm hoping to put some of my pieces back in to be re fired. Hopefully there's room, we shall see. I haven't had much success with re firings.
Pinched Tea Bowl, green to black satin matt
crawled glaze and not mature
crawled glaze and not mature
Ever heard of a Good News Bee? That's one pictured below. These little bees don't sting and sometimes hover in front of your face as if telling you some good news. This little guy has brought some good news to me. I know I can make big handbuilt vases and handbuilt sculptures, plates, wall pockets, and many other pieces of my own design, and have them make it through a cone 10 firing. I can research and experiment on my own with glazes, slips, oxides, and stains and have fairly successful results.
Also I've signed up for a class, (a new hive) in the fall at a different college in the next town. It's one day a week. I really do like reduction firings and I still have lots of cone 10 glazes, which are already mixed up, so I'd like to use them. I'll re make many of the pieces I designed over the last four months to achieve some nice fitting glazes. Please keep your fingers crossed for some pieces I'm refiring and the few remaining pieces I have in the glaze load firing right now. I also have several other resources in the works for firing cone 10 work, so I'll definitely be able to continue with cone 10 reduction work.
Good News Bee on Dusty Miller
by Linda Starr
by Linda Starr
I'm also going to start firing cone 5/6 clay at home. I almost fired a load this weekend, but didn't have the right cones for the kiln sitter. And we all know what happens when you don't use cones. So I'll get the correct cones this week. Also the pieces I designed over the last several months can all be made with cone 5/6 clay. Once I am proficient at firing my kiln, I may rent space to other potters in the area who need a place to fire work. I'll also be attending two workshops over the next month or so, so stay tuned for more information about them. Well it's onward and upward for me, busy as a bee, stay tuned for more from the good news bee in the future.
You must be absolutely gutted, I would be. I have poured over your photographs and read your words and I think you have diagnosed the entire fiasco correctly. I have one suggestion, but I may be too late if you are already ramping up with them again. The Clary Sage Vase and the tea bowls could be saved and sent in another direction with gold luster. I have done this with crawling and unfired areas. Just apply gold or silver luster to the effected areas and fire to 700 Celsius, but check your bottle it might be different for you. It can look incredible and much meant. Who’d be a potter and don’t ever mention Chrome oxide to me…ever!
ReplyDeleteOh Linda, what can I say, it's all so sad... I hate it when people don't take care or responsibility for firing other people's work with the respect and attention it deserves. And placing just one cone on 3 levels, and not using them... Damn!
ReplyDeleteAnyway, you have posted some very helpful comments there for us. The torch to melt the glaze where two pots are stuck together, sounds a bit nerve wracking, but makes sense, and sounds like a real godsend when nothing else will do the job!
The crawling interests me, as I have had that problem more often when a friend fires my work, but have it occur less often when I fire my own. It is particularly bad if I have used a glaze over slip. I realize that having good clean, grease and dust free work is important, but I do wonder if it can also be connected with an excessively rapid rate of temperature rise in the early part of the firing, especially if there is still any moisture present in the glaze. (Imagine all that steam under great pressure loosening the glaze.)
The under firing would also be a factor, with glaze pulling apart, but not being able to heal. One good thing with under firing is that you do have another chance to fire again to the right temperature.
Lovely bee photos. Glad you are able to find a new "hive".
Best Wishes, Peter
sh!t
ReplyDeleteThis was months of your good work.
All I can is agree about your own kiln working and learn how to fire it for the results you want.
Dang.
so sorry to read all this... i wish i had more experience with that kind of firing but not enough to diagnose anything. it's a shame to see, particularly that teadust glaze looks like a really nice glaze if it had come out. hang in there.
ReplyDeleteDear Kitty, thanks so much for your thoughts and ideas. I have reglazed the pinch bowls and they are in the kiln right now. I decided not to reglaze the clary sage vase because I got the blue where I didn't want it to go and I want the vase to be as I intended it. I also decided not to reglaze the crowded city vase either. I actually want to experiment with some lusters this summer on some other pieces I will be making, and I will start out trying them on some of the pendants I make to see how they do in my kiln. What about chrome oxide - please tell me more. I did use a copper carbonate wash on the green leaves and some pendants in this firing - could this have contributed to the problem? I used them during the bisque load though and they had already firmly burned out and attached themselves to the clay, but perhaps there was some residue if the bisque wasn't fired hot enough?
ReplyDeleteDear Peter, thanks for all your thoughts. I was amazed at the heating technique. When I used the torch on the pot it got red hot and then I just pulled the pieces apart. I believe the glaze on the leaf vase was harder than the glaze on the crowded vase, so one loosened before the other. I am still going to try and heat up that little piece and see if I can remove it and what it looks like underneath, but I believe this technique will be beneficial for any pot that might have a small drip on the kiln shelf. We had previously just knocked them off and more times than not, the pot broke but not the glaze so this would be a way of saving an otherwise perfect pot. I think you may have something there about the steam and rapid firing in the early part. When I visited the other college I had an opportunity to see their glazes and they were perfect. I have also taken these same glazes I have used here and had my pots fired elsewhere last winter and they have come out wonderfully, each and every one of them so it must have something to do with the way they are fired or the kiln at the present location.
Hi Gary, thanks yes you have said it like I felt it - as it all came out of the kiln. All was not lost as I learned a lot, but it is a hard lesson to learn.
Hi Jim, thanks, yes, that tea dust is great. Sometimes it comes out more black with very little dusting, but in this firing the dusting is really prominant which is nice. It's nice on a tall smooth surface so the tea dust is really visible and when the light hits it it reflects a bit.
Update: Below is a great resource someone sent me about trouble shooting glaze firing problems. After reading all about it, I have come to the conclusion that it would be better to fire like glazed pieces in a load to minimize the reactions between various glazes which is not possible in a community firing. With so many different glazes and different chemicals in each glaze being placed in the same firing, they are all reacting with one another in the kiln during firing. My use of copper carbonate could have also been part of the problem - it may have volatalized in the kiln although it was bisqued beforehand and some pieces with it did not have a problem. On to my own kiln and Cone 5/6.
ReplyDeletehttp://digitalfire.com/4sight/troubleshooting/index.html
So sorry to hear about the problems with this firing. That's upsetting for sure. Hopefully re-firing will save some of the pieces?
ReplyDeleteBut, I am so happy to hear that you have signed up for a class at another facility in your area! I hope that you get so much more out of it compared to your previous instruction. Good luck!
Oh, Linda! All your beautiful pieces ruined…bless your heart! I wish you all the best with your new class and workshops!
ReplyDeleteWhat a lot of disappointments after waiting so patiently for this firing. You are doing great at trying to figure out what went wrong and learning from it while planning how to move on. Why don't they use cones in the bisque? Thanks for the sharing your information and the link for troubleshooting.
ReplyDeleteYou said you used a jewelry torch to separate your pieces. I'm guessing it was acetylene or were you using propane? Good luck with the re-firing. I have had good results from re-firings. I hope your new hive is a good fit..
Hi Jerry, thanks, I do have a few in the kiln now, keep your fingers crossed.
ReplyDeleteHi Jewels, nice to see you here, Thanks so much, I plan on getting some good firings very soon.
Hi Barbara, I have no idea why they don't use cones, especially since they have a ton in the classroom, laxidasical I guess. We used a jewelers torch which is connected to some tanks in the classroom. I will have to ask what is in them. The guy that told me this says he uses an acetylene torch in his kiln, I think. I will have to recheck with him. My husband said the jewelers torch has a hotter and finer firing tip than just a plain acetylene torch. I guess in order to get the glaze hot enough it would have to burn as hot as it would to melt the glaze. I will check further and make another report on this technique.
Second Update: the person who had the glaze which sputtered all over the kiln, told me today the glaze which he used was peeling up and flaking off when he put all the vases in the kiln (on the top shelf). He put them in there anyway. Utter disregard for all the work below those vases - not to mention his own - he knew his own wouldn't turn out from the get go. I could see it was useless and futile to even discuss it with him.
ReplyDeletegosh, Linda how frustrating and disappointing! My fingers and toes are crossed for the refiring and the remaining glaze firing---- hang in there....
ReplyDeleteThanks Amy, it's firing right now, I shall find out Thursday night how it all turns out. I hope I get some good ones this time. Gary helped me bring all my glazes home tonight.
ReplyDeleteTime to move on- your work deserves better. The only way to do that is to bring the work home to fire. I remember how frustrating it was firing with folks who had no regard for the work of others.
ReplyDeleteYou are too smart and put too much work into these pieces to leave them up to others to fire.
On your own you will learn so much more and be better for it.
As they say, "just do it!"
I hope that your own clay adventures bring you all you want and deserve.
Hi Meredith, thanks so much for your words of encouragement; you and other have given me the impetus to get going right here. I am sure things will be turning around real soon. I have lots of ideas.
ReplyDeleteOh and I'll have lots more time if I'm not driving to and fro to class.
ReplyDeleteHi, Linda.
ReplyDeleteI'm thumbs up on the digitalfire.com recommendation. I use Tony's glaze calculation software in addition to his Website, and I have been very happy. He's busy working on the new versions of the software, but even so he has been very responsive.
I fire to cone 10 in gas reduction a lot of the time, and I really like the range of colors and effects I can get.
Keep at it and shed the discouragement as rapidly as you can, but:
A) learn as much as you can from the losses and "failures", and
B) do try to make sure that your work gets fired by somebody who understands cones.
There is a lot of good info about cones on the Web page of the Edward Orton Ceramic Foundation. (This is no surprise: in the US, most cones are manufactured by them, so they have a vested interest in having people understand how to use the things.)
About the pyrometer: if it uses a Type K thermocouple, it is nonlinear (and thus not entirely reliable) above about 2100 degrees. I use a Type S thermocouple on my gas test kiln for this reason.
Best --
jon
Hi Jon, thanks so much for all your info, I will check my pyrometer to see what type it is; I have now moved to Florida and don't have a gas kiln only electric, but I hope to get back to it one day; I still have my glazes, hoping it will be soon. the cones are a good indicator of the heat work and I am using them with my electric kiln too. thanks again.
ReplyDelete