Tuesday, November 23, 2010

A bad firing.... 3.5 out of 10! Or you could say... "yippee" 3.5 good ones!

There he is... poor old fellow, toiling into the night. I am fitting glaze catching saucers and stands to the pots.

It is not uncommon for me to work into the evening when I am getting pots ready for the kiln. It is a question of having to... Putting off the job until the next day, simply puts everything back another day, and could have me finishing firings late at night.

I am starting to get into a pattern that works for me with crystalline glaze firing. I try to get the kiln loaded in the afternoon or evening of the day before the firing proper. I am not raw glazing as yet, but I like to warm up the kiln to just below 100 degrees Centigrade, just to steam out any moisture from the glaze and the protective coating of alumina that I have applied to the glaze catcher. I might do this for 2 or 3 hours.

Just before bed time I start the firing by having the kiln on a low setting. Between 2 and 4 in the morning I get up and put the kiln on a medium setting. By now it is at about 500 degrees Centigrade and is starting to show a bit of colour from the spy hole. Between 5 and 6 in the morning the kiln will now be at about 700 degrees Centigrade, and I get up and put the kiln on full, and allow it to climb at its maximum rate until the top temperature of the firing.

Firing this way, the kiln can be at peak temperature by about 10 in the morning, have dropped to crystal growing temperature by about 11am, and I can work at growing the crystals for the rest of the afternoon. Whilst it means an inevitable broken night of sleep at the start of the firing, I do then have the luxury of doing the most tricky part of the process in the daytime, and can often fit in quite a lot of other work around the firing as well.


Scales... minor and major!

No electricity in sight when it comes to my scales... The small ones on the left were my grandfathers, and are much older than they look. The temporary pans are made from plastic Christmas pudding containers that I put on the scales when I was trying to use them to weigh larger quantities of raw materials than they were designed to hold. The bigger scales that are on the right, are ones I purchased from our local second hand shop. They have been one of the most useful things that I have bought for the studio.


Ho... Hummm, Oh dear..... not very nice at all!

We had a very busy weekend. On Saturday we held a pottery workshop for a group of about 9 or 10 people in Dunedin. I had been somewhat apprehensive about how it would all go, but it turned out to be a very enjoyable and productive day. My shelves are now bulging with small clay birds and other animals, vases, and bowls, which are drying prior to firing them about a week from now.

On returning home from the workshop, I had to arrange all the work on the shelves to dry, then load the kiln for a crystalline glaze firing. It was a very tired fellow that finally tumbled into bed for a few hours before getting up again to supervise the firing.


Close up of what glaze can do to insulating firebrick when alumina fails to protect it.

I fired through Sunday, and we also had our gallery open in the afternoon, and good friends visited for an evening meal. I hoped to achieve a different shape to the crystals in this firing, I changed my firing schedule and upped the growing temperatures a little.

The sort of mess that I have to grind off the bottom of the pot when things don't work as they should.

Sadly more than half the firing did not turn out very well at all as a result of this. The crystals were too big and mostly became a nasty shade of raw sienna. Sad..., but instructive!

I also ran into another problem. I use alumina as a "non stick" and protective coating over the glaze catching saucer and the insulating firebrick stand that goes in the middle of it. I had purchased some calcined alumina from a different supplier. Up till that point I had been calcining my own. Unfortunately the new calcined alumina did not work (I think it was too coarse), and all pots stuck very firmly to their stands, and the glaze got into the firebrick. I was very lucky that none of the pots fell over, as their stands were partly destroyed by the molten glaze. Patient work with a chisel, the bench grinder, and grindstone have freed all the pots, and I am tidying them up quite well... It just takes far longer than it should! Needless to say, I am calcining my own alumina as I write, and will use that in future.

Some more nasty pots.....

There are always lessons to be learned from a bad firing, sometimes more than from a good firing... I will try re-firing some of the pots, they are really horrible, and re-firing won't make them worse, and it will be useful to discover what effect another firing will have on both clay and glaze.

Not all was bad in this firing, happily there were some gems in the kiln.


This pot had nice crystals where the neck joined its shoulders.

It is a little odd on this side with the small patch of background showing through the covering of crystals.


This side has a little more background. I was pleased with the good strong outline.



Close up. Notice the crystal near the bottom with the blueish center and raw sienna outer.

This detail shows what, for for the most part, was a problem in this firing. The last two hours of the firing was at a temperature that was higher than the rest of the crystal growing period. You will see that the outer part of the crystals are mostly a raw sienna colour (especially in the crystal that is in the bottom of the photograph). The center portions of the crystals are often blue or gray, and when this part of the crystal was growing, the kiln was at a slightly lower temperature.

White....., ahhhh, isn't that nice! Titanium giving a nice touch of ivory to this.


This pot had a mirror finish. The glaze contains some copper carbonate, and some manganese.


I like the dark outlines and the relative amounts of crystal and background.


A warm flush of iron.

This pot had 2 glazes. A crystalline glaze with iron and cobalt under a crystalline glaze with manganese, cobalt, and copper. I love the strong flush of red that has developed. I find that the iron holds back the crystal development slightly, and this has been a good thing in this firing, where most pots were covered with crystals that had become too big.

And here it is on the other side...

Sales were good over the last week or so.. I said to Laura, that if I could manage to keep selling at that rate, my annual income would be similar to that of a teacher who had recently qualified!! (NB teachers went on strike recently... for more pay. Hey guys, hang around a bit or I'll never catch up!)

My Expenses this week were rather higher than earnings ..., I bought a lot of clay and.......

I saw the ENT specialist this week and an Audiologist. Both were very pleasant people and were able to peer into all the appropriate places and test things out. I have probably sustained some hearing loss as a result of my latest escapade, and my ears are not coping with pressure changes very well. I would not be able to fly as things are currently, but the ENT specialist was able to give me the good news that, if I want to travel by air again, I can have a minor procedure done to fit grommets to each eardrum. Many children with "glue ear" are treated in the same manner. In my case, this will allow the pressure inside the ear to stay the same as that outside the ear, and I should be able to fly pain free.

What I really need to do to help me afford to get my ears done is a "Jug for Jug" deal.. I wonder if the ENT specialist would appreciate a large jug in payment for each of my ears!

Just a thought......!

By The Way....
I just noticed that my profile has been looked at 2010 times which is quite appropriate for this year really! (and I don't think that it was just me checking to see if my profile has been looked at..., at least, I hope not!). Anyway, a big thank you to all of you who follow this blog, and take an interest in what happens in my part of the world. I have been fascinated to see, courtesy of Google's Statistics on this blog, that this reaches people in Russia, China, and Korea, and that some people have viewed my blog on Playstation 3, iPods, iPhones, iPads, and BlackBerries! Some of you must have wonderful eyesight and determination! So a big hello to you all out there... I'm waving appreciatively!!

11 comments:

Linda Starr said...

some real beauties this time, love the titanium white, I vote for the jug for jug, good idea, might be worth pursuing.

Dad said...

Yes, as you say 3.5/10 for results, but 12/10 for the effort - and the willingness to learn from what went wrong! How I wish that a lot of my pupils in bye-gone days had had that attitude!
Don't forget those regular times OUT!

ang said...

some stunning work there peter...and yep major lessons to be learned when we change things like ingredients and firing cycles!! You should try offering some of your lovely work in kind for a consult you never know :))

cookingwithgas said...

hey Peter!- yes it does count when you check- but you can rest assured you have not check 2,000 times!
Or have you......:)!
The keepers are real keepers- beauties- that iron...warm inviting.
Glad to "hear" you went to see doctors.
Are they as expensive there as here?
Here it would take 10 big jugs per ear.

Arkansas Patti said...

When I read of the hours you put in, I wonder if you worked for someone else that required the same hours if you wouldn't be filing grievances against such a cruel task master. You are one tough boss, but my goodness, the results are worth it.
If your give your ENT a pot for the proceedure, he owes you change.

Peter said...

Hi Linda,
The white pot greeted me this morning in the warm glow of the first sunshine of the day, and I must admit.., it is rather beautiful! Yes, I am warming to the idea of a jug for each ear... I will have to see if I can negotiate it!

Hello Dad,
You'll be pleased to hear that I am still trying to squeeze in a walk every day if I can... so am managing a little time out that way. I think that learning does help one stay "sane".. it is an attitude to life really, and definitely makes things more fun.

Hi Ang,
Nice to hear from you. I see that you are back to boiling temperatures in parts of Australia again, poor you. Anyway, that's a nice web site that you are constructing, so I hope you get lots of people having a look. Someone did say that potters aren't making any progress if they don't have at least one failure in each firing... So, I made a lot of progress this time!

Hi Meredith,
2015 now...or is that 2016 seeing as I've checked!! Ha, I wonder if Google have white coated number counters sitting at the other side of our screens in Google Land, scribbling furiously on their clip boards and adding up columns of figures! It is a funny thought. And what, ask all the conspiracy theorists.. are the numbers going to be used for??!! I guess there could be a form of gambling going on up there like that on the race horses...
Some Doctors do charge quite a bit out here too, enough for some private patients to have "holidays" in Singapore and other places to have private surgery done for less than it would cost here. It is a mixed bag really. We still are very lucky here compared to USA as some of the basic things or very life threatening things can be done for "free" in the public hospitals. But there seems to be a growing class of "none essential" surgery or testing that can only be accessed privately.

Hi Patti,
I should be closed down really... just as well that I am only self employed! My ENT is a she... and a very gorgeous red headed one too... I must give the jug for an ear thing a go... Maybe I'll make a profit. What a shame I don't have 3 ears!!

Armelle said...

Hi Peter,
What a nice titanium crytaline pot, now I know what it means !!!, hummm, the theorie ;-) I love the shape. Matthieu explains us yesterday the firing curve for crystaline glaze.
I wish you an automatic kiln, and enought time to sleep. I am really happy to know that the sales are good, so maybe, a new kiln ? Oh yes there are also the ears : two jugs, why not !!!

A bientôt

Pat - Arkansas said...

Your successes are beautiful... and the failures very interesting. You are a hard task-(self)master, Peter. It's evident that you love your work.

With the mixed news about your ears, I'm happy to know that there are procedures that would let you fly if you needed/wanted to do so. Your red-headed ENT really needs to work out a barter system with you; she doesn't yet understand what a great bargain that would be!

Peter said...

Bonjour Armelle,

The white pot found a new home yesterday (and a delightful one too), so it was not in my studio long! Sleep would be good.... Maybe an automatic kiln one day, but not for a while yet! My good sales now are making up for the few sales of winter, so I am like a squirrel storing food!

À tout à l'heure!

Hi Pat,
Success and failure... "Beautiful" and "Interesting" are a good way of looking at it. As I think about the pots that went wrong, I keep learning things, and solving little puzzles, so it is becoming quite a valuable firing after all. I have been glazing more pots, and will be finishing that process today and getting them ready for a firing that should take place tomorrow. So... let's hope that I can do better this time around!

I think that I am going to have to print out these comments and take them to my ENT..., how could she resist a jug for an ear deal with the splendid endorsement of my blogging friends! :)

Jewels said...

Hello Peter! It was good to hear from you – it is nice to be back! Your crystal glazes are amazing! The white is lovely and the iron blush! I am sorry you have hearing loss from your travel ordeal. Is there a chance you will recover it with time? Happened to catch Nigella’s namesake cooking something on TV while at a friend’s house and thought of you all. Take good care of yourself!

Peter said...

Hello Jewels,
Lovely to hear from you. I'm quite glad that our Nigella doesn't cook in our kitchen.... she is just as beautiful and purrs just as well as her TV namesake, but.. I don't think her cooking skills would be as impressive! The good news is that the hearing loss is really only for the high frequency range, so it is not really a problem. It just means that I probably won't be able to track mice or bats! For the first few days I couldn't really hear birds, and had difficulty understanding what children were saying..., but I can do that OK now. Yay!
The iron blush glaze is about my favorite out of that firing. It's almost as red as a copper red.