Stiff slab handbuilding with porcelain….

I’m still working on pots for my March show of white salt-fired porcelain.  I’ve got just about enough, but thought I would make a few more handbuilt vases for the load.  I’m working with Georgie’s Crystal Springs cone 10 porcelain, which has turned out to be a decent working clay if dried carefully.  Last night, I sliced a bag into three thick slices and let it start drying – or conditioning, if you will.  I am very particular about the stage of dryness for my handbuilt work.  I work with much stiffer clay than anyone else I know, and make just one pot at time so my clay stays just right.

Sometime back in the 60’s I took Soils 200 at Oregon State University; part of my education as horticulturist-to-be.  I remember that the Cove clay soil – which I was soon to know intimately –  was considered to be the archetypal Oregon clay soil, “2:30 Soil.”  At 2:00, too wet to plow…  at 2:30, too dry to plow.  My handbuilding clay is like that, with a teeny perfect window of time to work.  It has to dry enough to stand, but moist enough to flex a bit and join to itself on demand.

If I am stamping, or using texture mats, I will apply texture when the slab is still a bit soft; then dry it to the same stage as my clay to be carved. If you a reading this because you’d like to try this stiff-clay handbuilding stuff, you’ll have to find your own way with it.  At workshops, I pass bits of clay around so everyone can get a sense of how stiff is just right.

So here’s some just-right clay, twiddled around, covered and uncovered for a couple of days, and rolled out just a hair under 1/4″ thick.  I use paper SlabMat, so I don’t have to remove the canvas texture.1 Layout toolsHere are some of my layout tools, a big right triangle and a quilters’ rule.  The rule is 18″ long.  I want to make some tall standing rectangular vases, so I cut front and back each about 7″ x 12″. The end panels are 3.5″ x 12″.2 Score and Moisten

I don’t use magic water, vinegar, or any of that goo for joining.  I score all edges to be joined with a serrated rib, which is much quicker than one of those silly little metal brushes.  I line the pieces up and stick them together.  You can see that I have dressed the inner seam at the right of the image with the black water-buffalo horn tool – it’s better than a finger.

3 Stand it Up

Here are the two sides and the back, stuck together and standing up.  The clay has to be stiff enough to stand!  I do not use coils, they are a colossal pain and way too much work. These are approach joins, and they work well for me.  I have also beveled the edged in various ways, with various tools that I have gleefully invented, but in the end this method is faster, stronger, and looks just as good.4 Applying the Base

It’s easy to put the bottom on – you can see the slight distortion where the serrated rib has roughed up the clay.  No sweat!  We will fix that in an hour or so when the box/pot has set up a bit.  You can also see that there is a finished pot right behind that has already had strips of clay applied to the top edge to give a more refined appearance and strengthen the pot.  When I was learning to handbuild, seemed like everyone wanted to whack on their pots with wooden tools to strengthen the joins; all that has ever done for me is distort the pots.  Here’s a picture of how the strips go on the top.  If I am in a fussy mood, I will miter the corners by eye, but it works just as well to lay them in square.5 Trim the Top

I did put a couple of stamps on each front and back slab, couldn’t help myself.

Here’s that same pot about an hour later – er, part of it.  I used to try to finish all the surfaces at the time I did the building but have learned to leave the pots alone for a while and clean them up when they have set together strongly – at least 1 and maybe 2 hours.  I  keep a toasty studio in winter  and I keep the pots well away from the stove so drying is even.  6 Rough Joins Ready to Scrape

As you can see, I work on lots of clean newspaper and often on an old bath towel.  These edges are ready to clean up.  I will also take care of that little nick in the pot too, don’t need that….7 Microplane Smooth

The first tool I use is a fine microplane from the cookware store.  These tools are super for handbuilders.  I use mine for dozens of tasks, and they are especially good for working on square work because they are so flat and plumb. It’s fine if joins – or feet – extend a bit; they clean up fast with one of these tools.

The next image is a bit hard to understand, but it shows the tool I use to finish up the joins; a smooth oval rib.  Carefully applied, it scrapes away the texture left by the microplane.  I do like the microplane texture – and use it sometimes to surface small objects.  But I want a smooth surface on these standing vases.8 Oval Scraper

With all the edges finished, it’s time to apply the surface imagery.  Gotta start somewhere.9 Start Somewhere

I’m getting a bit weary of these flowers, but since people still want to buy  the pots I will keep making them.  I am a slave to commerce! 10 Handbuilt Dogwood Fin

Done with this one…  a similar design on the reverse, and geometric figures on this sides.

12 Finished HB Vases

Here’s the group from the work session, about 5  hours in at this point.  You can see that the one on the right is wearing a little bandage to compress the top…  I noticed that the top trimmers were separating a bit, so I filled the void with some very heavy body paste and bound it up with nursery flagging tape.  Every potter should have some on hand….   That pot came out of the bisque a couple of days later with the top tight and perfect.  Incidentally, I always make these pots last to fill my kiln, because they dry super-quick compared to thrown pots.  They are so even in section that they can dry overnight if needed.  I dried these under plastic just because they are not my usual compliant grey stoneware clay.

Here’s the one I like best….11 Geometric Box Fin


9 thoughts on “Stiff slab handbuilding with porcelain….

  1. paperstew

    Oh Ginger, I just love your work! Thanks for such a great post. I agree with Eva and hope you post images of their finished state. 🙂

  2. Pingback: Handbuilding with Stiff Porcelain Slabs | insomnia pottery

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