Wednesday, January 2, 2019

Happy New Year! A Cone 9 - 10 dolomite matte glaze for you to try!

I think that Santa and his cat must have gone fishing this Christmas, and the postcard that he sent me is evidence of this! The great day came and went in rather a rush and left us a bit surprised that it had been there at all. Laura and I were fairly tired in the run up to Christmas, so we had a quiet day at home, just the two of us... well, 4 really when we include the cats!

I did try to get this card finished and sent away on Christmas Day, but it didn't quite happen, so here it is now as a Christmas/New Year thing.

At this time of year it is usual for people to drop in! We were delighted to meet up with Gwynneth and Vic (The Pirate) who I have read about for several years now on "Ook?!" Gwynneth's blog. Gwynneth is a very experienced and accomplished potter and does lovely linocuts as well, and Vic is a retired aircraft engineer. They are currently in New Zealand intending to compete in cycling events at the Masters Games and were able to travel far enough South this time to come and see us.

It is lovely to meet other bloggers "in the round" as it were, and we made sure that we remained comfortably three dimensional by having an evening out with them and feasting together on yummy wood fired pizzas at "Salt and Sugar" the Karitane General Store in the next village!

Gwynneth, Laura and Vic
 Vic is 20 years my senior, and was able to confirm what the weather was like in the village of Rye where I was born on the day of my birth! Vic was taking part in a cycling event near Rye in the UK on that Blessed Day, and attests to the fact that the weather was just as appalling as it is in my mother's account of things! ("It was a dark and stormy night, my son, and the Midwife could not get to you in time....., etc"). Vic has a photo of another competitor sheltering under a cape as the rain pours down. What fun!

Meeting such lovely people is a happy/sad thing as there is always so much to talk about, and never enough time, but we are really thankful for the hours we had and for the enduring warmth of friendship.

Christmas, and the week or so after it, is an odd tumble of days which quickly lose their comfortable labels of Monday, Tuesday, Wednesday and the like, and today, which my calendar informs me is a Tuesday, really feels like Saturday because it is New Year. In spite of the uncertainty, I have managed to get a glaze firing through the electric kiln and should have some new bowls to put out in our little gallery tomorrow, all going well!

Recently I was pleased to rediscover one of my gazes that I had developed in 2014, a dolomite matte glaze that was intended to be a useful substitute for an old faithful glaze that I had used before when I could still get Cornish Stone at a sensible price... and "proper" Cornish Stone, not the less interesting substitute that you get these days. Real Cornish Stone from Cornwall UK was a fascinating material. A complete high temperature glaze in itself, this natural material contained the glass former silica, the stabilizer alumina, and fluxes sodium, potassium and calcium, with the interesting addition of a trace of Fluorine (if you were lucky!). Quite a nice high temperature clear glaze could be made from it by adding just a little more flux, such as 8 - 12 percent calcium carbonate.

By studying the chemistry of the various natural materials we use for potting it is possible to make reasonable substitutes in some cases, but they are never really the same as the natural ones, that doesn't mean that they are necessarily inferior, just different, rather like family members that look much the same, but have unique personalities!

At the time that I made the glaze, I did not do a great deal with it other than use it on a few test pieces, and 2 liters sat for 4 years in a bottle, not coming to any harm as such, but looking rather neglected! At the time I probably found the glaze OK, but not hugely inspiring on the rather iron rich stoneware clay I was using. Now I am using a porcelain body I am really delighted with the result.

Here is my Dolomite Matte recipe. This is a cone 9 - 10 glaze and I have only tried it thus far in oxidation, but suspect it will perform OK in reduction too. Best on porcelain or white stoneware. Stores well!!

Soda Feldspar    25
China Clay          25
Silica                   20
Dolomite             15
Potash Feldspar  10
Whiting                 5
Talc                       3

Total = 103

I tried the glaze on some rice bowls that I had "thrown off the hump", and I improvised some fish with brush decoration in cobalt and red iron oxide. The little bowls really feel and look just right so I am very pleased.

Happy New Year to you all!