Gas Firing 2016.02.20 Comments and Notes

This firing of the kiln went too long, resulting in Orton cone 11 flat.  Ideally, it would be cone 11 touching, then sagging a bit.

Upon unloading the kiln this morning, one thing was immediately apparent: the right side was far more reduced than the left. Yellower glazes and more slumping. Even on the left side there was some slumping, because of the excessive temp., and because of the clay which contained some low temp high iron clay to help seal the ware against leakage.

Left side, sagging only slightly, white surface.
Left side, sagging only slightly, white surface.
Right side sagging badly, white glaze turned yellow.
Right side sagging badly, white glaze turned yellow.

Chosen Karatsu came out pretty good, but the white was on too heavy, running down the pots too much.  It still came out looking ok because of the clay.

Most of the teabowls warped or sagged, so I only get to keep 2 or 3 of the 15. This is why teabowls are expensive, kids…IMG_3399 IMG_3398

All in all, not a bad firing, but need to adjust clay bodies, and pay closer attention to cones. Also, figure out the over reduction on the right side. It might be that one burner that sounds a bit off.

Kakewake CG bowls
Kakewake CG bowls
guinomi, need more sand in the clay
guinomi, need more sand in the clay
crystals, only grew on the right side, where reduction was strongest.
crystals, only grew on the right side, where reduction was strongest.
cylindrical tea bowls
cylindrical tea bowls
yunomi
yunomi
shells on feet
shells on feet

IMG_3437

saggared and much improved.
saggared and much improved.
porcelain, saggared
porcelain, saggared

IMG_3464 IMG_3463 IMG_3462 IMG_3460 IMG_3459

 

2015 Christmas Firing

was a real nail biter.  At 4am, 10 hours into the firing, I realized that I had not gauged my propane reserves properly, when I looked at the tanks and realized that they were only about 1/5 full and covered with a thick layer of ice. I immediately put the water hose on them to melt the ice and keep them from freezing again, then I chewed my nails until 8:30 am when I could finally call the gas company for fresh tanks. They arrived just after 9am, and good thing to because I only had about 2 inches of fuel left in the tanks at that point.

The firing ran a total of about 18 hours, which is fairly normal for this type of firing, and most things came out ok, with a few exceptions:

Fall 2015

has been busy.

I’ve gotten pretty far behind keeping up with the blog, falling into the bad habit of making small posts to Facebook. One of my areas of increased effort over the next year will be to work more on maintaining the blog, and getting it more integrated with other forms of social media. Trying to keep track of them all is like trying to herd cats.
I had made one promise to show before/after pictures for a couple of pieces, the first of which is the slab/paddle built sake chiller w/ feet and lugs:

IMG_2176
raw unglazed
IMG_2513
Fired piece, Chosen Karatsu style glaze. Matchbook for scale.
IMG_2518
Underside detail. Fired on shells, feet not touching the shelf.
IMG_2516
Glaze detail

 

The other thing I’ve been working on since early this year is getting a usable kohiki/clear glaze combination, because for some reason a lot of customers have been requesting white work. They have also been requesting black, so I’ve been working on getting a reliable semi matte black glaze. Mission not quite accomplished, but I feel I’m most of the way there. Here is the kohiki I’ve come up with and I am happy with it:

Kohiki cups. Cup on the left is unused. Middle has been used a bit, and right has been used a lot. The patina is beautiful in my opinion, and the fineness of the crackle is something I’ve been wanting for a long time in my work.
Various guinomi from 2015, mostly from the fall firing. Guinomi make great gyokuro drinking cups.
Various guinomi from 2015, mostly from the fall firing. Guinomi make great gyokuro drinking cups.
Seabirds on white.
Seabirds on white.
The other thing I have started doing is Japanese kana inspired brushwork
The other thing I have started doing is Japanese kana inspired brushwork, except with English. This cup is decorated with vertical English writing, a Goethe quote I like: “Whatever you can do, or think you can, begin it. Boldness has genius, power, and magic in it.” One of the other said: “Don’t be a dick.” These were more popular than I had anticipated and are currently sold out. Definitely making more!

Here are some of the pieces with the new black glaze. It seems to look best thin, and as with most glazes looks nicer over interesting wild clays rather than processed clays.

Type 1 semi matte black Katakuchi with black lacquer repairs.
Type 1 semi matte black Katakuchi with black lacquer repairs.
Type 1 semi matte black dish.
Type 1 semi matte black dish.
Semi mmatte type 2: two black glazes layered
matte type 2: two black glazes layered, makes a fatter glaze surface.

Fall Open Studio

Just a short post of some pictures from the studio sale this weekend.

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.

WD_1020

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.