Category Archives: tools

Loading it up…

I started loading the kiln on Sunday, but didn’t get very far. By Monday evening the rear setting was finally finished. For some reason the rear setting is time consuming. Today (tues) I started the middle setting and got it about half finished in 2 hours.

Here is the rear setting going in:
Fairly low temp glazes at the bottom rear. That rear bag wall has holes along the bottom for a bit of flow, but I want to see what I get there as far as temp and reduction with limited flow. Most of the rear setting stuff will mature at Orton cone 6-8.

 The plates on the floor should get nice and covered in embers. The top left, behind the beer mugs, has another large jar that is not very visible in the picture.

It rained all night monday night and this is what greeted me in the morning:
The water missed the mattress by about one cm. To get an idea of the depth, look on the left side and you can see the shovel handle.

 There is a black spot on the blue mattress and if you look closely you can see it is a frog. Unfortunately, he is dead. One of the neighborhood cats has taken to having his midnight snacks in my kiln. I wish he/she would clean up after eating…

 All pumped out now, but with the continuing rain, I have to turn on the pump frequently. I leave my sandals in front of the kiln when I go in and load. If I don’t pay attention I could get stranded in the kiln and my shoes would be floating around in that front area. So, I load pots and glance back now and then to check the water level, plugging the pump in when it gets too high. I REALLY need one of those automatic sump pumps so I don’t have to keep switching it on and off manually. The water made it into the firebox Monday night, but not up onto the front floor of the kiln yet. We’ll see if it gets any higher by tomorrow (Wed) morning.

We are expecting rain through Thursday, so I’m a little worried about finishing the front setting on Wed evening, then waking up Thur morning to find all the pots sitting in and inch of water.

Even with the front area pumped out, the wind has been blowing the rain in, making it difficult to load the kiln. I nailed up a tarp to cover the entrance area. Later in the year, I’ll extend the roof properly to keep things dry.

One last item of interest: The company that manufactures Seger cones (Japan uses Seger cones rather than Orton) was in Fukushima, and was apparently seriously affected by the recent disaster. Consequently, Seger cone prices have tripled. They were 200 yen (about $2) each to begin with, but can you imagine paying $6 for a cone?! I had trouble shelling out $2, so I switched to Orton a couple years back. It is still WAY cheaper to pay shipping on Orton cones from America than pay for Seger cones here, even when they were practically a steal at $2 each.

The maiden voyage of the Uber-Blend 5000 Turbo

 I acquired this piece of machinery, the Uber Blend 5000 Turbo, from a kindergarten that had used it for mixing large batches of powdered milk. It is basically just a very heavy motor suspended beneath a large reservoir, driving some wicked looking 4 inch wide mixer blades. It is so heavy that it needs its own frame to support it and stand it up. When mixing is done, the entire reservoir can be tipped down to decant the contents.

I’ve been doing lots of glazing this last week, and decided at the last minute to test a new glaze in the upcoming firing. This glaze is basically just stamped feldspar and ash, in a 9 to 1 ratio. Anyway, mixing up this stamped feldspar is always a time consuming, tiring affair, because it comes in cakes straight from the filter press, and is like a stiff clay. Getting this to melt in water is tough. If you let it dry completely, as I have started doing, it gets rock hard, but is easy to break into smaller chunks. I’d been slaking these small chunks in water over a period of days or weeks to prepare it for thorough blending with a drill mixer, but this time I had the Uber-Blend 5000 Turbo!

Here are some of the chunks of Taishu feldspar. These were the smaller ones, measuring a couple of cm across. The largest chunks were up to about 7cm.

The Uber-Blend 5000 Turbo, in all of its sleek elegance. It is an absolute chick-magnet. With this baby parked in the studio, who needs a Lamborghini?

This is 9kg of spar and 1kg of ash turned almost instantly to smooth, silky glaze, requiring NO screening. There were a few tiny lumps left after the initial 30 seconds, an additional 5 minutes of uber blending and they were history too…

And in conclusion:  IN YER FACE, Magic Bullet!

Happy potting everyone.

Two Birds

I was busy cleaning up the yard yesterday, trying to figure out ways to reduce clutter around the studio, and had an epiphany.  I could take all of the old electric kiln back up brick that I’d gotten hold of 7 years ago and lay it over the fiber layer on the wood kiln before covering it all up with more mud.

It was a quick, easy decision to make, and actually a quick, easy job. Finished it up in about one half day, and it should add a lot of insulating power to the kiln shell. Best of all, I no longer have a huge stack of orange crates filled with brick, covered with corrugated steel sheeting, sitting at the entrance to the property!

After all, and this is the eerie part, I finished the whole chamber with only a few bricks to spare, plus some unusable fragments. So, the left over brick pile, formerly home to numerous leeches and centipedes, and a few snakes, is now a nice extra layer of insulating brick on the kiln. In truth, the kiln looks like crap now with all of those different bricks sort of jigsaw puzzled on there, but once it has its nice mud jacket on, it will be spiffy and clean looking once more.

The first ‘test’ section.

 Continuing to the other side…

 All the way to the front, both sides, and the bricks are pretty much gone.

 You can see here the mix of bricks, B-1 and C-1 backing brick, and a few inner hot face brick with element grooves. Door lintel areas have some mud/rotten granite/straw mixture to support the bricks. Lots of room left around doors and peepholes to allow a nice thick edge of mud later. The mud mixture is really great, only shrinks 3% from wet to dry, and holds together like cement. Best of all the company will deliver it for about $80 for one ton, or $120 for two tons. It is originally made to be the under layer for roof tiles on old style tile roofed houses and temples/shrines.

Some more improvements

The first firing showed some of the flaws in the stoke hole cover for the front of the kiln, the first being not enough extra overlap around the edges, and the second more dramatic one being the loosening of the frame in the heat, causing the cover to fall out of its frame in the middle of the firing, which was an exciting event.

I cast a new, larger cover for the front stoke, and moved the original to the rear chamber stoke hole, where it is looking quite sharp and happy. The implementation of the frame for the front stoke was done a bit differently, just to see how it plays. I think it will be more stable, balanced and less likely to come apart during firing. At some point, I’d like to do a welded door, but for now this will work.

Here is the cover assembly. I had to drill holes for the rods, but it allows for the angle iron to be oriented across the center line of the slab.

 Detail of the angle iron, threaded rod, and shims. My plan is that the shims  allow for the angle iron to be tightened to a slight bow, and hence to be in a state of tension, so that when the frame heats up in the firing, there may/will be a loss of tension, but the frame will remain tight and secure around the slab.

 Here it is hanging in place. Twisted 2.1mm stainless iwire on the cover assembly. 3.2mm stainless wire twisted around another threaded rod, connected from the overhead beam. In the first firing there was no discernible softening or stretch in the wire (2.1mm) from the heat, so this 3.2mm wire should last a good long time.

The next improvement is by mother nature, who is giving us our first really good bunch of wisteria blossoms:

The coverage is a little sparse, but with a few good prunings over the next couple of years, this little gal should fill in nicely. I’ll post pictures again when the blossoms are in full bloom.

A nice surprise

Yesterday I came home to find a nice surprise sitting in the drive. A 5 inch thick slab of Keyaki (Japanese elm). Last year I had asked a sawmill owner friend of mine if he could locate one for me, and it took a while but he really came through.

I am going to use it to build a new kickwheel, a low wide one that is good for making large pots. Two 20 inch pieces, the flywheel and wheel head, will be cut from this slab, and trimmed round. The hardware will be made from porcelain, rather than tempered steel like my upright kickwheel. I think it will be an interesting project to make things the traditional way.

If you want to see my upright kickwheel, there is a post on it in the archives of this blog.

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Making a homemade paddle 2

After burning the paddle, take a soft brush and brush the surface clean of the carbonized matter. I use a brass brush for this, or sometimes stiff plastic. Steel is too stiff and will scrub out your hard earned texture. Use water during the brushing process, or you’ll end up looking like a coal miner after a hard days work.

When I looked at the old pots, the surfaces were sometimes pocked with odd bumps, bumps which didn’t look intenional or man made. Finally realized this could have been from wormholes in the paddle used to make the piece. Lacking access to highly trained, hungry pine beetle larvae, I used a rusty nail held in a vice grip to burn texture similar to worm holes into the surface of the paddle. Holding the vice grip away from you heat the nail until red hot with the burner, then jab and drag it into and across the paddle to create your texture. Use your imagination, have fun!

Burn and brush again to knock off the sharp edges from your texture and you’re finished! I don’t usually burn texture into the whole surface of the paddle, since different parts of the paddle can be used for different effects.

This paddle was textured with saw cuts before burning for the crosshatch design.