The Official "Ask the Artisan" Community Topic


Artisans share their TeawareArt.

Re: The Official "Ask the Artisan" Community Topic

Postby FiveStar » Jul 3rd, '14, 01:59

Anyone have any recipes for glazes to share for raw glazing? I've got no access to an electric kiln for bisquing, so am limited a bit in that respect. I've got some simple shinos that are working nicely, but would love some more options. Nuka? I'd love good ash glaze recommendation too.
User avatar
FiveStar
TeawareArtisan Member
 
Posts: 47
Joined: Dec 12th, '

Re: The Official "Ask the Artisan" Community Topic

Postby Petr Novák » Jul 3rd, '14, 06:34

FiveStar, I am not sure if it will help, but here are some thoughts on both questions you have had:

For Gaiwans: As usually with ceramic, there is no simple answer to that...here are some points to consider, here are some of them:

what kiln/firing we are talking about? It will be like heaven and hell if you are going to fire those pieces in fast fire kiln for 10-20hours(for example kind of phoenix kiln that we have) or in angama for 6days, with heavy ash deposites.

What clay do you use? I use, for my shibos 5-7 different clays+their mixtures. I prefer to have unglazed rim, so the lid can sit there during firing. But just one, maybe two caly are suitable for this combination: thin body, open shape, woodfiring. What happens with other clays, when the lid is not fired on pot, is that the lid, pot or both warp in fire. Sometime just a little bit but then it makes “unhappy” gaiwan user.

Unglazed gaiwan does not offend me either. In that case, for longer firing (more ash expected) I would use wadding kind of snake all around the lid. In case of glazed gaiwan. I would think twice where in the kiln to put it and hope for the best...Very often I say to this kind of questions: try and you will know for the next time, it is quite difficult to give any advices when I am not seeing your kiln, pots, not knowing clays, glazes, firing...

As for the raw glaze advices, generally, all more clay (high alumina) glazes are better for raw glazing. So start with slip glazes if you have any, you can even make some experiments to put regular glazes over those slip ones. Nuka can work, but just on some clays and will be quite tricky to glaze with, count with some losts during looking for the way how to glaze.

Happy day, happy fire
Petr
User avatar
Petr Novák
 
Posts: 339
Joined: Feb 19th, '

Re: The Official "Ask the Artisan" Community Topic

Postby paul haigh » Jul 8th, '14, 08:56

I single fired for a few years after I built my wood kiln. The general rule is that most glazes will work with the addition of a couple percent bentonite (this should be added to the dry materials, mixed in the dry state, then add water to eliminate weird clumping effects like you see when adding flour/corn starch to a sauce).

I will add- I personally had more success glazing at the "black hard" stage than bone dry, for the same reason it's hard to rehydrate leather hard clay with most glazes.

I recall one particularly disheartening episode of a whole board full of mugs spontaneously disassembling after dunking them for shino tests.
User avatar
paul haigh
 
Posts: 129
Joined: Apr 4th, '1
Location: Londonderry, NH

Re: The Official "Ask the Artisan" Community Topic

Postby FiveStar » Jul 8th, '14, 14:03

Thanks for the helpful replies Petr and Paul! I'm having good luck with simple neph sy/clay shinos at the moment, and am happy to hear about the bentonite. I've got one shino with soda ash that has 5% bentonite in it, so may try that on some test pieces.

Having a day job, and being a part time hobby potter certainly doesn't leave me with much time to get these experiments done! Firing in August, so hopefully I will find the time to make up a few test batches of glazes.

Thanks again!
User avatar
FiveStar
TeawareArtisan Member
 
Posts: 47
Joined: Dec 12th, '

Re: The Official "Ask the Artisan" Community Topic

Postby Bok » Oct 8th, '14, 22:20

Hello, had posted this question in another part of the forum, but as someone suggested it probably makes more sense here… :D

Here it goes:

I was wondering about the procedure for the wood firing.
More specifically I am not sure if everything labeled as “wood-fired” is actually the same thing.

An example, here in Taiwan wood fired pottery is extremely hard work and needs usually be done by several people.

The clay wares have to fired for three continuous days and the temperature in the oven should not fall under 1000°Celsius. That means someone has to watch and put a big wood log in about every 10-15 minutes. They even have to watch the smoke coming out of the chimney to indivudually adjust airflow and other things. That is why usually several potters use one oven together to share the workload. It then cools for a week before they open it.

They told me that with this procedure the clay has certain properties which are favorable in a tea pot when compared to a normally fired/glazed pot.
That said glazing can be used with the wood firing as well, the items just need to be protected and put into larger items or specially made containers.

Is anyone willing to share their procedure?
Bok
 
Posts: 23
Joined: Aug 4th, '1
Location: Taiwan

Re: The Official "Ask the Artisan" Community Topic

Postby paul haigh » Oct 14th, '14, 08:18

Bok- The amount of time required is related to, amongst other things, the size and style of kiln. I know several potters in the US and elsewhere that fire for a lot longer than 3 days (9 days is not unusual). Even similar kilns may fire fairly differently, as they seem to have personalities.

My kiln is relatively small- I fire for a total of 40 hours. I developed a system of firing over 3 days, slowing down the process, which leads to better results in my kiln and allows me to do the whole firing myself. The majority of wood kilns are fired around the clock. I have fired it flat out for 24- 30 hours with people working in shifts, but results were not as good for this particular kiln.

The first day I fire for 10-12 hours, up to 100C to dry everything out(a bit higher at the end). The second day I get the kiln to about 450 C for 10-12 hours just to distribute ash and soak some heat into the bricks. The last day I fire 20 hours, getting the kiln to about 1250- 1300 C for several hours of that. In total, I burn 2 cords of wood- which is almost half what it would require to heat my drafty log home in a New England winter!

It is a lot of work- even for my little 45-50 cu ft kiln, it takes a couple of long days just to load the work. I have loaded it without gloves in 1 C temperatures and slush, in -10C and snow, and I have fired in 35 C (The kiln doesn't make it any cooler). I fired last week and have still not fully recovered, even though I had help from a young energetic potter that wants to learn (I get mostly stiff hands and feet, but am exhausted and achy for days). I'm not saying this to complain, just to put it in perspective- the experience that you heard of from those potters is universal.

John Baymore has a larger, multiple chamber kiln. You may see us joke a bit here about the joys of wood firing. Most customers picture peaceful throwing at the wheel, and a nice little fire in the kiln like a camp fire with friends and drinks. With all that work- I still get butterflies in my stomach getting the kiln loaded and ready. Of course, I always say that I'd lose a finger for a good story.

Here's the fire coming out of my 5 meter chimney by almost 2 meters- it's no joke, even on a small scale. https://www.youtube.com/watch?v=JmoRvurASH8
User avatar
paul haigh
 
Posts: 129
Joined: Apr 4th, '1
Location: Londonderry, NH

Re: The Official "Ask the Artisan" Community Topic

Postby Bok » Oct 15th, '14, 00:13

Hi Paul,

Thank you very much for your long and informative reply! It really seems the suffering is universal for this kind of firing – but I think the results are worth the sweat!

I am sure it would be more appreciated if people knew the scale of work behind… My teacher recently had an exhibition here in Taiwan and people mostly went for the glazed stuff. I guess in Japan, the US and Europe there is a better market for the wabi-sabi estethic of the wood firing. If I have a choice I will always pick the wood firing.

I am lucky enough that our teacher allows each student to put in one piece each time they do a wood-firing. Just wish my skills would be better, almost feels like a waste to burn my beginners pieces…

Every kiln opening feels a bit like christmas, you never know what you are going to get! I am always fascinated by the colour and texture range that is possible.

Here in Taiwan you won’t freeze anything off, just get eaten alive by the mosquitos and enjoy double the heat with the climate plus the fire coming off the kiln… everyone his own pleasures isn’t it? :)
Bok
 
Posts: 23
Joined: Aug 4th, '1
Location: Taiwan

Re: The Official "Ask the Artisan" Community Topic

Postby paul haigh » Oct 15th, '14, 07:49

I'm opening my kiln tomorrow, after 6 days of cooling- it really is tough to wait!

We are all still learning. The people that are not learning bore me. If I stop learning- I will bore myself.
User avatar
paul haigh
 
Posts: 129
Joined: Apr 4th, '1
Location: Londonderry, NH

Re: The Official "Ask the Artisan" Community Topic

Postby FiveStar » Oct 16th, '14, 20:20

Welcome Bok!

I've helped fire in 2 kilns, one being an anagama, and the other being a 3 chambered noborigama. Both start firing the same, with a fire built outside of the firebox. We run like that for about 18-24 hrs, and then begin moving the fire inside after the preheat. At that point, we're shooting for 100degrees per hr of temp gain approximately till we reach bisque temp. At that point, once we start to reach temp at the face, we stoke to hold temp there, and begin moving the heat back through side stoking.

The Anagama usually fires for 4 days total including the preheat, and the noborigama fires in about 3 days solid. We do various charcoal introductions at the end of the firing in the anagama and in the front chamber of the chamber kiln. The 2nd chamber of the noborigama reaches cone 10 in about 8 hrs or so after the front is to temp. We load glazed ware in that chamber. 3rd chamber takes about the same amount to finish, and gets a big charcoal intro at the end.

Tons of work, but the results to me are worth it!
User avatar
FiveStar
TeawareArtisan Member
 
Posts: 47
Joined: Dec 12th, '

Re: The Official "Ask the Artisan" Community Topic

Postby Bok » Oct 17th, '14, 02:49

Thanks FiveStar!

Hats off to all of you artisans who put so much work and effort into it!
So it seems in regards to my initial question that wood-fired is not wood-fired, that there are lots of different methods and most likely a wide range of colours and properties the finished product can have.

Did any of you notice a favorable effect on tea when using wood fired teaware? My teacher mentioned that the heat retention is better, he spoke of the fire of the long process that kind of stays in the clay. But that might be a chinese way of expressing it… He said in that way those pots can be similar to Yixing ware. The normal fired clay has no real effect on the tea brewing, acording to him.

In my own practise, I can say that the wood fired pot seems to stay hot a tad longer than a normal. But to be objective I guess I would need to use two identically shaped and sized pots, which I don’t have at the moment.

Might be an experiment worth trying. Maybe I get there, once I am able to do identical teapots… still far from it :mrgreen:
Bok
 
Posts: 23
Joined: Aug 4th, '1
Location: Taiwan

Previous

Instant Messenger

Permissions
You cannot post new topics
You cannot reply to topics
You cannot edit your posts
You cannot delete your posts
You cannot post attachments
Navigation