Tag Archives: ceramics

Rainy Season Is Here

A lot has happened over the last month since the Karatsu pottery festival, mostly cleaning, shelf building, and shifting things around in the studio in preparation for the open studio event which happened this last weekend from June 19th to June 21st.

In rough chronological order, here is what has happened in May:

Plates formed over wood slabs of various sizes

Paddled slab plates en masse...
Paddled slab plates en masse…

We got our garden planted and our first Jalapenos soon followed!

This year's small Jalapeno crop. Not many, but it's a start.
This year’s small Jalapeno crop. Not many, but it’s a start.

Another type of crop: Good batch of Madara Karatsu guinomi from late April firing. Body is mostly crushed sandstone with a bit of native low iron clay to help keep things together.

Madara Karatsu guinomi from spring gas firing.
Madara Karatsu guinomi from spring gas firing.

In prep for the open studio event, I cleaned the deck and brickwork of the backyard. I did not realize just how overgrown with algae and moss it had become until it was clean again.

The deck and bricks after being power washed. Almost like a new backyard.
The deck and bricks after being power washed. Almost like a new backyard.

One of the worst sections, but it felt really cathartic blasting all of that green away, leaving nice clean trails of clear, brown wood.

Before After pic of the deck, what a difference!
Before After pic of the deck, what a difference!

Entrance to the yard event space, tents and blue tarps up to  keep out the rain. Luckily, although it threatened a few times, it never really rained, and the last day was actually sunny and hot. This is  the middle of monsoon season folks, we totally lucked out.

Emeth and Shimauchi san's burgers. Best burgers in Nagasaki. Best burgers in Saga for 3 days only.
Emeth and Shimauchi san’s burgers. Best burgers in Nagasaki. Best burgers in Saga for 3 days only.

The spot for gamblers. 500 yen per turn, no losers. One grand prize, 15 second place prizes, 25 3rd place prizes, and 100 4th place prizes. One grand prize went out every single day of the 3 day event. Happy customers!

Pot lottery wheel. No losers here, everyone walks away with a pot, some better than others...
Pot lottery wheel. No losers here, everyone walks away with a pot, some better than others…

This discount table was a new strategy for me. Turned out to be great for turning older pots into cash and additional storage space in my studio showroom.

My discount table, holding everything I haven't sold in 6 years that I couldn't bear to hammer. I think about 300 of these pots found new homes.
My discount table, holding everything I haven’t sold in 6 years that I couldn’t bear to hammer. I think about 300 of these pots found new homes.

Knife and tool maker, really nice stuff for reasonable prices

Knives and tools from Matsubara forge, in Nagasaki.
Knives and tools from Matsubara forge, in Nagasaki.

Really big caterpillar!

A friend I discovered during the open studio event. Never seen one like this before.
A friend I discovered during the open studio event. Never seen one like this before.

My favorite studio tool…

….is without a doubt the Peter Pugger de-airing pugger/mixer. Until two years ago I did all of my clay and stone mixing in a large deep platter by hand, and it was killing my wrists.  Hearing all the wonderful things Peter Pugger had to say on their website, I took the plunge and decided to spend the money and save my hands. I figured if the thing worked half as well as it was supposed to, I would be ok.

Well, it is now about 2 years since I got it and it does everything it is reputed to do, and does it very well. My wrists are now pain free, and I have saved hundreds of hours of time processing and blending clay bodies.

Blending wet clay bodies usually takes about 15 minutes of mixing, but mostly I mix dry materials with water (sometimes blending into wet bodies), and this takes a while longer, usually around 30 minutes.

In my work, keeping the character of the wild clay is of utmost importance, and I’ve found that de-airing generally kills that character dead. However, the de-airing is necessary in getting the water to penetrate the dry materials more quickly, so that I don’t have to let the pugged clay sit for a month before using.

My solution to this is to let the clay mix, then I de-air it once completely, followed by re-mixing the batch for 5 – 10 minutes after reintroducing air. This gives me clay that is not as easy to throw, but which gives very nice trimmed texture.

Here are some pictures of some clay from the other day which I collected from the mountain behind my home. I added the dry/damp clumps of clay to the hopper (removing as many large rocks as I could find), then water, then mixed. I repeated these three steps until the hopper was full, then mixed for about 20 minutes, turned on the vacuum pump, and de-aired completely.

Next I went to lunch.  It was yummy. It was sunny on the deck and there was a cool breeze. The neighbors have a  great cherry tree in full bloom and the wind was blowing the petals off, and they were fluttering across the yard like giant pink snowflakes. I noticed as I saw some of them fall across the deck that the wisteria was budding out and even starting to show some purple. Nice. I imagine the wisteria will be in full bloom a few weeks early this year.

After coming back to the studio, I re-introduced air to the mixing chamber and mixed some more, then pugged it all out and made some pots. The whole process took about 2 hours. It takes even less time if you decide not to include lunch, but I recommend including it.

What I’ve been up to…

I had a gas firing a couple of weeks back which was mostly line blends and other glaze combination tests.  More than half of the ware in the kiln was glaze tests. Finally trying to get to the bottom of my Chosen Karatsu glaze woes, which started after my ash source changed. Both of my bread and butter glazes stopped working, and it now seems that I just made a spectacularly bad choice for my replacement ash. I tested 3 different ash types in the load and came up with two types that seem to work pretty well. I will mix up small amounts of both glazes with this new ash and  see how they work. If things look good, I can then go ahead and mix up a larger batch.

I made a batch of soba choko as well, to take with me to Tokyo toward the end of this month. I’ll be participating in a small event and needed some small things to  take and show.

In prep for the spring firing of the wood kiln, I’ve started making work a little different that  I have done before, more playing with rim shapes and putting feet on things. The larger platters  are actually inspired by some old Shino and Karatsu pieces of similar shape. Almost everything pictured in this post is porcelain, either pretty white stuff, or ‘dirty’ having been run through my pugmill which contained red stoneware previously. I always hear how porcelain is so difficult to work with, but my experience is the opposite. It seems very forgiving compared to my usual short, large particle clay bodies.


Red Lungs

Getting ready to set up a whole kiln load of glaze tests to fix my misbehaving ame (iron/ash) glaze, and realize that I’m out one very important ingredient, red ochre collected from a place right here in Taku. Completely forgot that I had used the last of it in my last glaze batch mixed up a couple months ago. Doh!

So…. Delay the mixing of test glazes for tiles and cups, I had to spend the day crushing and sieving red ochre. I haven’t used my man powered stamp mill in a while, and I added too much material to the mortar. My wooden pestle (4 foot long pole) that I use to stamp the material was just not up to the task because it was too light to sink down into the material and get it circulating in the mortar.  To remedy this, I retrofitted one of my wooden pestles with some  3cm diameter round steel bar left over from a long piece of bar I cut into sections for my kiln’s grate bars.

This new pestle worked really great, so great in fact, that material was flying out of the mortar from the striking force. So I proceeded to cut down a large cardboard box to keep most of that stuff from flying out or away. It is really hard work digging it, carting it around, and crushing it, I hate to lose any at all.

So anyway, here are some pictures of today’s festivities, and I did wear a dust mask, so I don’t have to worry about getting red lungs…

Mortar full of material, big chunks.
Mortar full of material, big chunks.


My two 'pestles'
My two ‘pestles’
retrofitting with steel bars
retrofitting with steel bars
Now we're in business!
Now we’re in business!
Things moving along nicely now.
Things moving along nicely now.
Sieving. This is one of the jobs I dislike the most.
Sieving. This is one of the jobs I dislike the most.
This bucketful is sieved through 50 mesh. Before using it, I will re-sieve through 80 mesh, most likely.
This bucketful is sieved through 50 mesh. Before using it, I will re-sieve through 80 mesh, most likely.

Crazy stuff

Lately I’ve been working on ways to bring out the crackle in my teabowls, as well as make the crackle finer (without having  to use them for decades or centuries, or reformulate my glazes,  so in other words: cheat).

These two bowls had big crackle ( 1cm +-) and I reheated them, then doused in cold water.

***WARNING: Ceramics generally don’t like to be heated or cooled quickly. Don’t do this if you’re going to be upset about breaking a bowl!***

For the kohiki bowl, I heated and doused once to make the crackle smaller, then reheated to open the crackle wider, and closed the damper on my stove, to get that carbon to penetrate the crackle.

Because the body and the glaze were vitrified, but the white slip in between wasn’t, spots (where the slip was thickest) on the rim separated from the body and had to be restored with lacquer and gold (*1)

The results vary, and it is high risk, but you can get an idea about how your bowl may mature over years of use, and plus it’s just fun to play around with fire…

Another common way to bring out the crackle in you ware is to boil it in a pot of strong tea for a few minutes. The tannins will then turn brown, especially if you put the piece out in the sun to dry (or any other UV light). For an even darker, quicker reaction, after the piece is dry, apply some iron acetate. The iron acetate reacts with the tannins and turns quite black over a period of 24 to 48 hours. This is actually an old woodworking technique that I applied to pottery, and it works well, in addition to being non toxic.

***Results may vary***

(*1: I didn’t use real gold for this bowl, but I would on a very nice piece. For this piece I used a brass based metal powder. For more info on this kind of repair, check out Dave Pike’s blog, or store on Etsy)



And so it begins…

Two years ago, my supply of stable dobai 土灰 dried up. I bought up the remaining stock from the supplier, but that didn’t last long. When I switched to another source of dobai, the results were far different than what I had imagined. My two main bread and butter glazes haven’t been the same since.

Which brings me to my current predicament of having to basically start from zero and re-formulate these glazes with different ash. Fortunately, I have basic analysis info from the old ash, and also for the new types I will be testing with, so I can use glaze calculation software to calculate substitutions, which I am hoping will give me a head start.

For your daily dose of trivia, the word dobai is rendered in kanji as tsuchi 土, and hai 灰, or  ‘dirt ash’ (which makes no sense to me). All other ash has a proper name, like pine ash, oak ash, fern ash, etc… I finally found a possible explanation for this odd name the other day when I was searching for ash sources on the net. Turns out the ‘do’ of dobai is actually shortened from the original name ‘kamado’, which is a large pot used for roasting, cooking, burning stuff, etc. It is easier to say dobai, than kamadobai, after all, I guess…

Here are my 3 main candidates for testing:

WD_7EA2I picked up one kg of each, and will narrow it down to just one. They are all about 10 dollars/kg, expensive right?  I make my own pine ash because I have a good source of already burned pine, but I’m not set up to process large amounts of ash, and when it is all said and done, spending 10 dollars or more per kg is cheaper than the time and sweat put into making my own ash. Rice straw ash is more expensive at almost 20 dollars per kg and it is still worth it when you take into consideration the gathering, burning, quenching, floating, stamp milling, 2nd floating, (ball milling in some cases), and drying process this ash requires.