Tag Archives: clay

The heavy table

I made this table about 5-6 years ago with the intent of using it with guests downstairs in the studio, but as things filled the space I never had a place for it, and it ended up under the staircase for the duration. It had literally never been used  for its originally intended purpose and gathered dust. Until a few days ago when I started rearranging the studio. Now with the stairs out of the way, it is out, clean, and ready for action. I scrubbed off 6 years of dust and crud this morning and started thinking about how best to use it.

If you haven’t noticed already, this is a huge grindstone (one of a pair I acquired), and it must weigh at least 200kg. Somehow I was able to get it up on that railroad tie frame with the heavy duty casters underneath so it can be moved. The current top is actually the bottom, and the actual top is slanted, so one side is propped up on two short kiln stilts so the table top is level. The grooves are close enough together that cups can sit without wobbling or falling over.

It occurred to me that the depression in the center would make a good improvised receptacle for tea goodies, and a garbage can could go under the hole for waste disposal. One other suggestion was to place a bamboo section in the whole as a small waste basket. One of the railroad ties partially overlaps the bottom of the hole, so the bamboo doesn’t fall through.

The freshly scrubbed table, about 80cm/32in in diameter.
The freshly scrubbed table, about 80cm/32in in diameter.
table surface detail
table surface detail
Fresh section of bamboo cut for the waste basket.
Fresh section of bamboo cut for the waste basket.
goodies, with wrapper disposal in place.
goodies, with wrapper disposal in place.
Mmmmm. Nice steamy tea on a cold morning...
Mmmmm. Nice steamy tea on a cold morning…

Snagged a new wheel!

I managed to get my hands on a used wheel, cheap. It is a gigantic banding wheel: wheel head is 50cm across and the whole thing assembled weighs 60kg. It looks like it might have been someone’s homemade wheel, made from acquired parts and put together.

It is an oddly constructed wheel, no bearings at all. The top of the shaft accommodates  a pin in the wheel head like my kickwheel, but there is no bearing in the bottom, just tapered sleeve on the shaft that engages the bottom of the wheelhead shaft, heavily greased. It requires a very fine setting of the tapered sleeve. Engage it too much and the wheel doesn’t turn well, not enough and there is a waggle in the wheel.

It arrived pretty rusty and dirty, looks like it saw a lot of use at some point, then got left in a corner somewhere for a few years. I got a wire brush disc for my angle grinder and spent quite a while getting the accumulation of clay, gunk, paint, and rust off.

Removable wheel head shaft
Removable wheel head shaft
Base shaft
Base shaft
wheel head
wheel head
tapered sleeve
tapered sleeve
The whole shebang, still dirty.
The whole shebang, still dirty.
wheel head assembly oiled and ready.
wheel head assembly oiled and ready.

Finally got the wheel head assembly cleaned up and oiled, and with some experimentation found the ‘sweet spot’ for the tapered sleeve when engaging the wheel head shaft, and the wheel spins quite nicely. Click on the link below to see it spin:
Wheel spin test

My plan for this wheel is to weld arms to the base of the wheel head shaft and mount a wooden fly wheel, and add a wooden wheel head onto the current steel wheel head. The resulting kickwheel should be great for onggi style coil and paddle work.

New helper in the studio

I traveled to the port at Nagasaki this morning to pick up my new studio helper, a Peter Pugger VPM-20. Once I got it home, it was a breeze to assemble and mount on the stand, and it was up and running in no time.

plugged in and ready to go

Excited to get it working, I grabbed a bucket of dry scraps and some softer clay, and started mixing. It took some time to figure out how to get what I wanted out of the machine, but I think I’ve figured things out for the most part. It really seems to need to be full to do its best work. Once I added enough material to the hopper, things really started moving along. The first pugged clay was too soft, so it got put in again with a lot of dry crushed sandstone and mixed. I just kept adding more dry sandstone until I got what I wanted.

the first time through was too soft and got run through again

I turned out still to be quite a light batch. After turning on the vacuum, pugging out the contents, then digging out the remainders from the hopper, I had a batch of almost 12kg. The beautiful thing was that because the whole batch had been de-aired, even the unpugged remainders were very easy to wedge by hand. In the past when I have mixed as much sandstone in as I did today, the clay has been largely unwedgeable by hand, being just too short and falling apart.

vacuum pump is working…

pugged clay next to what remained in the hopper

All clay bagged and ready to go

I think this machine and I are going to be great friends. It allows me to mix and process clays and other materials that were previously impossible to process just by hand. Oh, and it is very quiet, both the main motor and the vacuum pump are much quieter than I had been expecting.

A Nice Spring Morning Walk

Last Wednesday, I went fishing at night with friends. We arrived at our spot and while parking the car noticed dozens of large toads out in the rain. It was still cold out, we all had several layers on plus rain gear, but those toads looked comfortable enough. My friend said that this was a sure sign that spring was here, and so far he’s been right. Every day since Wed. has been downright comfortable, though it still cools down in the evenings. Millions of years of instinct trumps the weather man every time…

This morning on our walk, the smell of spring is in the air. That bite in the wind is gone, and the air is suffused with a humidity  not present in the winter months. This morning the cloud cover is thick and some rain will surely follow. The mountains are shrouded in mist, and the vegetation seems to soak it up. Everything is green and lush, unopened buds starting to swell.

Raz and I head up a new mountain road, the concrete is white and unstained, with just a few fallen twigs scattered over the surface. In a few years it will be grey and covered with pockets of moss and lichen, grass will be emerging from cracks and crevices holding the residual soil of the mudslides that will intermittently cover the road, only to be cleaned up by men or washed away by subsequent rains.

Even the forest is clean and uncluttered. Someone has been here clearing out the underbrush and deadwood, leaving behind a carpet of ferns broken only by the trunks of large trees. A few smaller trees have emerged as well, living in the shade of the canopy. Where the mountain was cut to build the road, there is green netting covering the soil with sodded grass slowly covering everything. In some places the grass was too slow to fill in and the rains have caused the clay soil to slide down to the raised curb at the edge of the concrete.

View down the mountain. The road is visible in the shadows of the forest.
View back up the mountain from the patch of road in the forest shadows.

When we reach the apex, about where the road starts to descend again, there is a clear cut area which looks like some sort of construction project in its early stages. Behind a large berm is a concrete gutter which has been installed to keep the water from encroaching into the project area, but clay and soil has fallen in, trapping rainfall in pockets several inches deep. In one of these pockets, I see several clusters of what are probably frog eggs.

Frog(?) eggs. At least 2 different kinds.

The clay exposed in the cut above the gutter is interesting. It looks very red, almost purple in places, and it has a lot of some sort of rock interspersed throughout. In one or two areas there is even some clay that looks fairly white. Perhaps it would be good for making pots. The red clay and the dark stone might be good for putting in a glaze. It may be worth a trip back up in the car with some bags and a shovel. Chances are once this project gets underway, I won’t have access to this clay again.

Iron rich clay matrix with some sort of grey stone inclusions. Shale maybe?
The whiter section of the clay bank

Coming back down the other side of the mountain, there is a cedar grove where a group of guys from my neighborhood have started growing Shiitake mushrooms. Lots of hardwood logs arranged standing up and in the shade of the trees. The logs are in that ‘A’ frame standing pattern to allow for good air flow. That, plus shade and rainfall equals lots of nice fat Shiitake. It takes about 3 years from when we inoculate the logs for them to start producing mushrooms.

Shiitake growing area w/inocculated logs arranged and growing mushrooms.

 

A little guy growing from one of the logs.

Handle Diapers and Stretchy Clay

The last couple of days I broke down and made some larger mugs and tankards. I generally avoid handled forms because most of the clay in my studio is not suitable. If you make a coil and bend it around your finger, it just cracks apart instead of bending. This time, I mixed a bit of plastic clay into the normal stuff to try to improve its plasticity. The mugs threw fine on the wheel, but again, when it was time to make the handles the clay was crap.

At first I tried pulling handles from a large ‘carrot’ of clay, but once you wet it, two pulls and it would be cracking apart and dropping off in your hands. Taking a different tack, I rolled out some tapered snakes, like Opossum tails but less stinky, and tried altering and attaching those, but when I tried bending them around to attached at the other end, they just cracked apart. The very few that didn’t crack ended up cracking a few hours later as they dried. Doh!

So this brings me to the current discussion of handle diapers. Sticking with the Opossum tail method I rolled out some coils. Then, before pressing them flat, I stretched a piece of plastic wrap over them. Making sure the plastic wrap was good and stuck to the clay, I attached the flattened handle to the shoulder of the cup, then turned the cup over and set it on the edge of the table.  Grasping the tapered end of the handle and the plastic, I lifted up the handle end and attached it. If any cracks appeared they could be eliminated by pulling on the two ends of the plastic which compressed the handle. Or, rubbing the clay through the plastic would erase them too. Leaving the plastic on, I placed them in styrofoam boxes to prevent rapid drying, hoping that it would also help the moisture to equalize between the cups and the handles. Today, I checked them after about 18 hours and they seem stable. None of the handles show signs of new cracks and they have firmed up nicely. The plastic is still attached but has puckered a bit from the shrinkage in the clay. It will be interesting to see if these dry completely without cracking.

Several years ago I ordered 100kg of white clay from Seto for making some Shino and Green Oribe ware. Never got past the experimentation stage for various reasons, but the clay is still taking up room in the studio so I decided to break it out and use it. I was double bagged in thick plastic and is still quite soft after almost 5 years. Unlike the Karatsu ‘clays’, this stuff is really clay, the stretchy kind, and it was great fun to play with. I made 600 gram lumps and threw some beer tankards. Then, pulled some handles and attached them, no fuss, no cracking, easy. I could get used to this stuff. It was so easy I decided to make some more this week for the firing at the end of Feb.

Kishidake Clay

Although I dig a lot of my own clay, every now and then I find a bagged clay that I like, and use it for certain projects. Since getting the big wood kiln, I’ve done more of this, because I can blow a lot of clay in one firing, and wasting collected clays is a real waste of time and effort. Once I’ve nailed down how to fire the woodie, I’ll go back to my collected clays since my loss rate will be much less (or at least here’s hoping).

Shoko Todo in Ureshino has a couple of clays I like, one of them is called Karatsu Kishidake because the base clay in the formula is from the Kishidake area. It also contains a lot of very fine sand, which is something I really like. Still, I like to add things to bagged clay to improve it, and this is no exception. If a lot of fine sand is good, then a lot lot must be better, right? Perhaps not.

I started by adding about 15% of my own sand to the clay, and to my surprise it improved the workability, giving the clay more backbone. It also gave the trimmed surfaces more character.

For the next hump, I added about 25% extra sand. I should have known I was in trouble when I couldn’t even wedge the stuff without it splitting apart and having chunks fall out, sticking to the table more than the clay lump. When I started throwing the hump on the wheel, pots would split vertically as I pulled the walls, and I couldn’t get near as thin as with the 15% sand/clay mix. Most of the bowls I managed to finish still had rips in them that I had to go back and fix later. When trimming, this clay gave a very rough texture, and I really liked it, but not enough to go through the frustration of throwing the stuff again. Although, for small things like guinomi this clay is the bomb.

Below in the pictures are two trimmed feet for comparison. One is the 15% mix and the other 25%.