Saturday, August 10, 2019

Tis the Season: Raku!

It was raku week at Portland Pottery, at least in my classes. I'd actually been planning these firings for a few weeks, but I always build in time for unexpected obstacles: in this case, the bisque schedule, some brutally hot weather (Al Gore was right!), and my own Lyme Disease diagnosis - more on that later.

Here's our Instagrammable moment:

Many thanks to students for great camera work:
It begins.
Got my good side!
Ooo fire!
Almost done!
The process is fun and exciting, and I try to do it with each class during the warm months, because in a communal studio like Portland Pottery, students get very little experience of firing. There are racks where they place their work to be fired...then the pots go away for a while...then [something happens, who knows what]...and the pots come back changed. I'm exaggerating a little - I talk to my students a lot about firing (too much, some might say!) and when the kiln is firing I bring them in to look into the spy hole. It's not the same as loading, keeping an eye on the firing, and unloading, though. Raku allows student to participate in each step, and to be responsible for the outcome.

Speaking of, we got some great outcomes:
Terra sigillata & horsehair

Portland Pottery (and your so very truly) will be offering a raku workshop Saturday, September 14th! Bring 4-5 bisqued pots of an appropriate claybody, and wear long pants, closed-toed shoes, and cotton clothing.
You can use a claybody that's specific for raku, or any groggy stoneware will usually be fine. High grolleg porcelain performs surprisingly well also! To register call (207) 772-4334.

Thursday, August 1, 2019

C is for Slab Building

I have some students who are exclusively slab builders, so I have been searching recently for new techniques to show them. Found this one described online, do I decided to give it a try.

It starts with a rolled slab, about 3/8s of an inch. I find a very common mistake among students is to roll their slabs too thin! In addition to being much harder to build with, an overly-thin slab results in a flimsy pot that chips easily and, to my mind, feels cheap. I can think of reasons why you would make a thinner pot - sometimes you can use daintiness in an aesthetic way, for special-occasion pots, in which the very fragility of the piece proclaims the specialness of the occasion, or makes clear that this is a decorative, not utilitarian, piece. But if you mean to use it regularly, give it a little substance!

But I digress. Where were we? Oh, yes, the slab. Once rolled and thoroughly compressed, cut two concentric circles. This will create a ring of clay, one circle being the outer diameter and the other the inner. The difference between the larger and the small of the two will be the height of the walls. The greater the difference, the harder this will be to build. To minimize any such difficulties, you want tgive this slab a little while to firm up. How long depends on the air conditions; 15 minutes is a good starting point but on the humid day I built mine that was not nearly enough. Building on a drywall board is helpful, too, as it allows the slab to dry from both directions.

Save the circle bit from the middle! It will become the bottom.

Now we're going to cut a wedge out of the ring, which will make a "C" shape. The wider the wedge, the more vertical the sides will be; a shallower bowl will be harder to build and may need to rest in or on a mold.
Like this one! This bowl is not especially shallow, but I lost
patience waiting for my slab to dry in our humidity. 

I found a wedge of at least a quarter of the ring made a good, useful shape.

Now we're going to bend the slab so that the edges overlap. There will be an opening in the middle.

Scoring & adding clay slurry (or magic water, or vinegar, or whatever your attachment preference) is going to be key in holding the seam together.

Now for the bottom. The circular bit that was cut out at the beginning is a little bit drier now, let's use that.

Optional, of course, but I like to put a texture on it.

This textured circle becomes the bottom - TWIST! - from the inside. Score, slip, etc, then:

There is, of course, a lot of smoothing, paddling, and other futzing - especially on the bottom! - to make it look nice.