Friday, December 24, 2010
Happy Christmas 2010! A wide range glaze recipe for you!
Talk about the weather!
Here the sky is mostly blue, but we are being buffeted and abraded by strong winds.
The wind has been coming and going most of the week. Sometimes it is a hot wind, and then it will shift and become cool. On Tuesday we had temperatures that reached the early 30s and the gales were strong enough to bring down trees, cut off power, and actually shred the leaves that remained on the trees. When it had all calmed down, I was amazed at the smell of freshly cut grass that hung in the air. It was actually the smell of the damaged leaves!
On Tuesday evening, the moon had a big bite taken out of it and turned a peculiar colour. It was an eclipse, and we had a good view of it as we traveled back to Waikouaiti after seeing friends in Dunedin who had organized an evening of Christmas Carols at their lovely house, which is called "Captain Eady's Lookout" at Portobello. Our friends, Richard and Ana Good, run a bed and breakfast at their home, and if you are planning a trip to New Zealand and want a marvelous place to stay that is near Dunedin, do get in touch with them.
Mugs in Crystals... and pots too!
At some time I did manage a crystalline glaze firing, and have done the first prototype mugs just to assess what a crystalline glaze will look like on the side of the mugs, and how much it will run.
I have also fired some pots and vases, and am particularly pleased with a couple of the crystalline glazed pots that have been glaze fired a second time.
One of the other crystalline glazed bowls (shown below) that I fired in this firing, turned out particularly well, with just one glaze firing.
All about bowls!
Early this week I decorated some bowls that I mostly intend to give to people as Christmas presents, and I unloaded them from the kiln this morning.
The bowls were decorated with a simple clear glaze, and decorated on the glaze with cobalt blue, and/or raw umber, and yellow ocher brush decoration.
The decoration was made up as I went along (I was too muddle headed to plan anything), and I really quite enjoyed it.
I have not really tried using umber and yellow ocher in this way before, and I do like how they have turned out. I have often thought that umber should be useful in, or on, glazes, as it is really a natural clay that contains a lot of manganese and some iron. Yellow ocher is clay that contains a large amount of iron. I fired these bowls to about cone 8, which is about 1240 Centigrade (2264 F) in my kiln.
Umber gave me a colour that is almost identical to burnt umber in watercolour, and yellow ocher gave a useful warm orange-brown with just a hint of yellow where the colour was thin. One nice thing about umber and ocher is that it is less "strident" looking than a stain, and far less expensive.
A glaze recipe for you.... Happy Christmas!
Here is the glaze recipe that I used. The glaze is from "The Potter's Complete Book of Clay and Glazes" by James Chappell, which was published by Watson-Guptill in 1977. I don't know if they will do me for including the glaze here.... but, in the spirit of Wiki Leaks, here goes!
The nice thing about this one is that it works over a wide range of temperatures. I have used it with great success from cone 6 to cone 9 (approximately 1200 - 1260 Centigrade 2192- 2300F ), but the recipe claims to work from cone 01. As the glaze contains quite a lot of zinc, it is intended for oxidized firings, but I have used it occasionally in my wood fired kiln without problems. Used at the temperatures that I have tried, the glaze should give you an attractive satin surfaced glaze that is semi opaque at cone 6 to clear at cone 9.
Satin Matt Glaze Cone 01-9
Zinc oxide (calcined) 9.8
Feldspar (Custer) 50
Kaolin (EPK) 17.6
+ Bentonite 2.0
Note 1 It may be a good idea to used calcined zinc for this glaze. This will help avoid crawling, especially at lower temperatures. If you use ordinary zinc, just use the glaze thinly and you should not have any problems. You can easily calcine zinc by putting a kilogram or two into a bisqued bowl, and putting it through a standard bisque firing, somewhere between 950 and 1020 Centigrade (1742- 1868 F). Do not fire higher than this though, or the zinc will form a hard lump!
Note 2 Don't panic about using Custer feldspar or EPK Kaolin, I just use what ever potash feldspar and kaolin I can get, and it seems to work nicely.
and.... it's Christmas Again!
It has been a somewhat difficult month. Both of us got sick with a tummy bug at one point, not a major event, and we are OK now, but it left us tired and made us late and slow to tackle the many pre Christmas tasks that we needed to do. When you are self employed no one else steps in to magically keep things going when you are sick, so... you just keep going if you can. Pots still need to be glazed and fired, shelves filled, orders met, the gallery opened, plants watered, leaks mended, tap washers replaced, gutters cleaned.... you get the picture!
I still haven't written a Christmas letter as such, I'm somewhat behind with Emails, and not many cards have been sent. The poor old blog has been gathering dust, and my web site good intentions have not developed far! Laura has been making a valiant effort trying to send some cards to people who just might receive them before Christmas, but.....as for the overseas cards that we were going to send..., hummmmm. Very sorry most of you!
Anyway, "'tis the season to be jolly" so "jolly" we shall be! :)