Tuesday 6 May 2014

Floral (dahlia) inspired stoneware garden pieces

And here are the finished fired pieces that I was glazing at the weekend. Unfortunately they are not good enough to be able to sell, some cracks and bits fallen off (which are disguised in the photos!) But they are good enough as prototypes now I have worked out the best way to build them so they hold up during the firing processes.

Here's the one with aqua-blue glass detail...

Ceramic stoneware floral decorative piece with aqua blue glass
Ceramic stoneware floral decorative piece with aqua blue glass
Ceramic stoneware floral decorative piece with aqua blue glass - detail
Ceramic stoneware floral decorative piece with aqua blue glass - detail
And the 'antique' pink one...

Ceramic stoneware floral decorative piece with pink glass
Ceramic stoneware floral decorative piece with pink glass
Ceramic stoneware floral decorative piece with pink glass - detail
Ceramic stoneware floral decorative piece with pink glass - detail
And finally here's some detail of the glaze - taken with my squidcam macro lens. The glaze reacts well with this clay and shows some of the buff colour and reacts with the iron(?) in the grog to give a speckled effect. It also shows a delicate crackle when seen close up.

Semi-opaque off white glaze on grogged crank clay
Semi-opaque off white glaze (Potterycrafts P227) on grogged crank clay


Monday 5 May 2014

Glazing floral inspired stoneware garden pieces

We're going to be moving house soon, which has given me the impetus to finish some of the pieces I have been working on so they are less delicate and more easily transportable. This also means I can photograph them and get them on my Etsy shop too.

I've had two large floral stoneware pieces hanging around in the 'in progress' shelf for some time now - no excuse for them not being finished other than laziness. So today I had a day to myself and prepared these to and some test tiles for a stoneware firing.

I'd previous glazed a similar earthenware piece in a shiny white glaze, but wasn't really happy with the finish. I knew I'd be able to glaze these two in a more subtle glaze.

Here's the first one (an identical form to the earthenware one) being glazed - pouring the glaze over it over a large bowl.

Glazing a stoneware floral piece with P2227
Glazing a stoneware floral piece with P2227
The glaze I am using is P2227 from Potterycrafts. This has a nice subtle semi-opaque off-white quality that works well with the glass. I'd used this before on a prototype piece but was keen to try it was a different glass colour.

Once the glaze has dried there is a lot of touching up to do by hand as the pouring method doesn't cover every part of the piece. Luckily the glaze is quite forgiving and tends to even itself out where application is not even, and will show interesting variations in opacity rather than highlighting drips and edges. After that is complete I upturn the piece and wipe excess glaze from the base before returning it upright and adding the glass. I use glass nibblers to cut pieces of glass from a sheet and drop them into the petals. During the firing the glass melts and flows so its not necessary to be too neat.

The second piece with  'antique' pink glass. The piece is more sunflower or daisy-like.

Glazed stoneware floral piece with pink glass highlights
Glazed stoneware floral piece with pink glass highlights
I've finally worked out that the easiest and safest way to get these into the kiln is to add the glass with the piece on the kiln shelf, so I can just lower each shelf into the kiln rather than handling the piece itself. Much easier!

Glazed stoneware floral piece with aqua-blue glass highlights
Glazed stoneware floral piece with aqua-blue glass highlights
There are being fired to:

  1. Up to 600ºc at 150ºc per hour
  2. 600ºc to 1260ºc at full ramp
  3. No soak
  4. Cool down
The kiln is cooling down right now but they will be out in the morning! Watch this space.

Sunday 4 May 2014

Ceramic herb markers - an easy process to repeat

Being my most popular item on my Etsy shop (not exactly a lot of competition there though) I decided to start producing these markers on a larger scale, and attempt to fire a whole kiln full in one go. So I got to work creating as many markers as I could to fill the kiln.

Here's the first six sets drying on a plaster bat.

Stoneware herb markers at 'leather hard' stage
Stoneware herb markers at 'leather hard' stage
Here's how I create the markers (mostly written for me to refer to in the future). I roll out the slab to a depth of 6mm, using wooden beading to get the correct thickness. Each marker is based on a 13cm long strip, which is cut using the width of the wooden beading (approx. 3cm). The tip of each marker is then cut to a point with a wet blade. I've found that the wet (clean) blade makes a much smoother and easier cut that a dry blade. I use an old kitchen knife for this. Oh and the clay I'm using is crank (stoneware) which is grogged and gives the markers a nice grainy rustic appearance.

I then use hot metal type to imprint the lettering. For these I use 48pt perpetua lowercase. I imprint the whole word (or as much as possible with one of each letter) in one go -  this keeps it a bit neater and stops individual letters being 'squashed out' by the next letter. I find that leaving the markers to part-dry on the plaster bat gives a cleaner and neater imprint. If the clay is too wet it can stick to the lettering, or even come off in the enclosed bits of the characters (e.g. in the 'o', 'p', 'b' etc.)

Once the markers are completely dry they are bisque fired:

  1. Up to 600ºc at 150ºc per hour
  2. From 600c to 950ºc at full ramp
  3. Cool down

With just four shelves in the kiln I managed to get thirteen sets of five markers in the kiln.

The next stage is to apply the stain to the lettering. For this I use copper oxide powder mixed with water, just a tiny amount to get the powder into a suspension so I can pick it up with a watercolour brush. I apply this to the indented lettering allowing it to pool in the letters but not worrying too much if it gets on the surface of the marker.

Here's what they look like at this stage

Stoneware herb markers - bisque fired with copper oxide stain applied
Stoneware herb markers - bisque fired with copper oxide stain applied
The next step is the wipe the excess oxide off the surface. This is best done with a moist (clean) sponge. The bisque fired clay will try to absorb the oxide, so its best to wipe this off with one clean stroke, I've found that pushing the sponge onto the surface to release a small amount of water 'pushes' the oxide into the lettering and then the rest wipes away easily.

Finally the glaze is applied. I've switched to using P2227 from Potterycrafts. It's semi-opaque and works well with the stain and also gives the clay a speckled 'oatmeal' appearance. I dip the upper side of each marker into a shallow tray of glaze, wait for it to dry then wipe any excess from the underside so it doesn't stick to the kiln shelf. This glaze doesn't run so you don't need to worry about leaving too much of a gap between the glaze and the bottom.

I place these directly on a (batt-washed) kiln shelf and fire them:
  1. Up to 600ºc at 150ºc per hour
  2. From 600c to 1260ºc at full ramp
  3. No soak
  4. Cool down
Results and photos of the finished markers in a follow-on blog post.