Saturday, 28 September 2013

Post 123 Making bonsai pots

This picture documents a milestone in number of changes in the way I've been working. What you see here are five bisqued pots about to be glazed.

The three at the front are compound ovals or bowed wall rectangular pots. I've pretty much abandoned making straight walled rectangular pots. They really are a great challenge to make and keep the sides flat and straight. If you don't get it quite right then they very clearly are not right. There's something to do with the unresolved drying stresses at the corners which are fine at bisque firing but then come into play at maturity, causing the right angle corners to come in a little dishing the walls inwards. This can be countered at the right time in the drying cycle by opening out the right angles and then bringing them back again, but it's all a bit subjective, and hard to get just right.

This new shape which can be replicated easily for any size is far more forgiving and the rounded corners distribute the drying stresses much better. Not to mention also that it is a good looking pot shape that will accommodate a wide variety of tree species and styles. I've made a few like this before but it's going to become the new normal from now on.

You will see also that the smaller pot of the front three is a different colour. That's the last pot I've made in RGH, and I hope it is the last I do too. The other four pots are made from Clayworks YG Yellow Stoneware. It's yellow when fresh and a more terra cotta colour at bisque and apparently sandstone colour at maturity. It is a 45# clay and so just a little grittier than RHG but good to work with. Shrinkage has been 5 % wet to dry/bisque. These are the first pots in this clay that I've taken to this stage, and three of them are commission pots so they need to work out.

And the other milestone is the work table and slab roller. As you see this is my universal work space with the slab roller bench at the end. I've made all these pots with slabs rolled out with the roller and it has been a treat to use. Making a wider slab produces a much better result with fewer joins, more easily. Joins are a problem not so much because they fail, which they don't, but because sometimes you just can't entirely incorporate them so they can't be seen in the finished pot.

So it's a matter of new clay, new technique and new shape all about to be tested in a 5 pot glaze firing. Not quite the right experimental process but ................... watch this space!

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