Monday, July 25, 2011

So pretty, Oh so pretty

Winter's arrived in all her glory. With snow falling to sea level from one end of the country to the other. Not much fun for doing pottery although I did some turning yesterday, but it will give me a chance to photo and log the salt glaze tests I've done recently. Here are some images of the icy conditions.       

So cold -minus 5 degrees Celsius according to the pyrometer.
From the inside looking out. I won't be doing much down here today. I have more turning to do but drying times have gone from two hours in the height of summer to three or four days in the middle of winter.

Yesterday the snow began falling but I still got some plates trimmed up.

Horses turned out and given a feed.
Summer studio and house in background. I won't be potting here till spring,when I will get into making big pots again ...can't wait.
The woodshed well stocked with dry kindling (sticks, leaves and twigs) along with split pine, macrocapa, acacia and eucalyptus.     

Interesting that the olive oil has congealed with the cold, but not the canola oil, something to consider at this time of year when trying to get the stuff through a fuel line.Not that I'm in any hurry to fire anyway as I have to pick up more second hand fire bricks for the wicket, at least three large shelves that will be cut down to size and switch to a buff stoneware clay for some more pots.

Two blogs I've been looking over this week are peters pottery  by Peter Gregory, who has been blogging since January 2009 and appears to be specialising in crystalline glazes, raku and kiln building amongst other things, and Brandon Phillips' blog Support your local potter blogging since February 2007,  has some great pottery books and equipment up for sale at the moment. Well done fellers, have a good week everyone.

PS Rest in peace Amy Winehouse,another brief but bright candle added to the infamous 27 club.

Monday, July 18, 2011

Cylinders, Lids, Cats, Batts and Galleries

Sun,snow, spring. With daffodils up and fruit trees blossoming, one could be forgiven for thinking its spring already . Twenty years ago I worked as a nurseryman, growing natives and grafting rhodies and stuff, and for the first time the strangest thing happened. Many species of plants that only flower once a year began to flower twice a year and now while I look out the office window I think to myself I have never known a Dunedin winter with so many cloudless days. Roll on summer.                                                              

A good sized cylinder using three pounds of clay. Like a bare canvas or a fine piece of marble, awaits a human touch to give it color and form. From here I will roll over the top then add the gallery for the lid.

A good deep gallery with no sharp edges and curved rim.

I prefer to throw on a wooden bat whenever possible, as I despise the grey metal oxide the aluminium wheel heads release in abundance.

Throwing lids off the hump.

Spurf (short for Sir Purrflous) content and able to make the best of any situation, contemplates...nothing much.                                   

Measuring gallery with calipers.If working with 3 pounds of clay for example I'll measure and document sizes so lids are of a standard size.This makes it possible to replace broken parts and throw lids the next day with out being concerned about shrinkage

A view of the water supply at the back of the shack. The horses won't drink it and neither would I but it seems OK to wash up in.

A dinner plate.

and a soup bowl. A good way to mix it up a little and keep my throwing fresh is to spend a day throwing bowl, cylinder and bowl forms. Whereas I often spend a day or a week throwing bowls for example, even this has no limits to size, shape the curl of the lip or the turning of the foot.
Over the last couple of weeks I have enjoyed looking over other people's pottery blogs. Its great to be able to see whats going on, not only globally but what potters have been doing over the last twenty four hours and even over the last several years notably Ang Design blog and Joy Tanner Pottery blog. Nice work guys. Have a nice week.

Sunday, July 3, 2011

Work in progress

July already, where do the months go? It's close to the middle of winter and Dunedin is yet to see a decent frost. This would be the first year the lawns didn't stop growing, maybe due to the Chilean volcano or a nuclear winter, but it sure makes for some great potting weather! Here are some pics of work in progress.                  
Some miniatures and some scaled up pieces with lids. As they get bigger I may have to add  handles and lugs.

Yesterday I added a work bench and more robust shelving. This small room off the throwing area is where I wedge, store and recycle clay, place pots on the shelves to dry and have a bucket of creek water to wash up in.

Here are a few test glazes from the previous firing using sump oil as a fuel. This is Marcus O'Mahonys " Light orange slip" The recipe is:  Porcelain clay (dry weight) 20 ( I used the white stoneware clay body) China clay 10, and Tin oxide 3. All recipes on this post are found on pages 232 and 233 in Phil Rogers book:  "Salt Glazing".

Here is the same glaze but on a buff stoneware clay body (southstone) All tests were dipped at least twice to get variations in glaze thickness. Note the interesting pattern around the top of this example where the glaze was quite thick.

A very typical salt glaze effect. This mottled texture is called "orange peel" and consists of an extremely simple glaze of just two components: Ball clay 50 and China clay 50, fired to 1300+  with plenty of salt.

In this example of Arther and Carol Rossers' "Blue slip" consists of : Feldspar 15 (Indian ), Silica 8, BBR (clay ceram)?? 30.5 (I used Kingwhite kaolin), Eucalyptus ash 15.5 (washed pine ash), Titanium dioxide 0.5, Cobalt Carbonate 1.  Now that I look at this recipe it doesn't resemble the original much at all. Part of the joy of pottery is the unexpected.

Another A+C Rosser Glaze "Green slip to be sprayed over blue" However,  this example shows only the green slip - a very beautiful glaze on its own.  I still have the test pottle, so in the next firing I'll try it over the blue slip above.
 In my next firing,  I will be using bigger batches of glaze on larger pots and firing a slightly bigger kiln.  I'll be using canola oil from the fish and chip shop, and comparing this to sump oil -  hopefully getting similar results.