Monday 5 March 2012

Post 5 - Glazed stoneware pots


Somewhere along the way the dreaded work got in the way and here we are by now in November 2011.
Making pots is still the focus and for that first glaze firing I applied some of those previously mentioned commercial glazes to a couple of my stoneware pots. These are not small pots and so dipping is out of the question – the volume of glaze needed would be huge. I masked the areas I wanted to remain unglazed (regular masking tape), like the feet and then applied the glaze with a soft brush; three coats.

 
 
  
This one was with a Northcote glaze – SG277 Mottled Blue Grey. As you see more gloss than not. Note also the crack in the pot on the far side. This happened in the bisque firing and I tried to use the glaze as a filler and bonding agent, which worked reasonably well. Next time I’d try to pressure inject the glaze into the crack. Clay is interesting stuff – it has a strong positional memory. Unless it is ‘well trained’ when still mobile it can and will struggle against the position you put it in to go back to where it was, right through to final firing. So the learning here is train it well and then don’t leave it too late in the air drying process to make a correction to the shape or those stresses you impose late will find a release in firing.


 

 This one was with a Northcote glaze – SG277 Mottled Blue Grey two coats with a top coat of SG624 Jade. An interesting mix of colours and closer to a satin finish.
 


 And this one is with three coats of the Northcote SG624 Jade. It was fired to 1240C and came out quite matte.

The three pots demonstrate the challenge of maintaining dimensional stability from shaping through drying and then firing. Through all that time the pot is shrinking – first through the loss of moisture and then through vitrification – by about 15%. So don’t be surprised when you look at hand made pots which have funny bends and deformations. And the bigger the pot the greater the challenge. Different manufacturing processes for factory made pots are designed for greater scale, faster production and greater stability. The craftsmanship in a handmade pot is in its individuality of form and finish, it is in the bumps an bends and happenstance. I can provide that individuality right now; the straight, square, aligned pot may take a little practice, but it is the goal. I talk to my kids about being really good at doing anything as long as you put in your 10,000 hrs of practice. I might be really good at it by the time I don’t need to make any more!











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