Monday, 20 October 2014

Post 178 Seasonal development - grow and cut

In south east Qld we are having perfect growing weather not to hot and not too cool, like goldilocks porridge, just right. This is very typical of our spring weather before the real heat and humidity strikes. Our trees have had a good run over the last 6 to 8 weeks and that time is pretty good for a grow and cut cycle here. We can get anywhere up to 4 or 5 of these cycles to build bulk and ramification.
I’ve got a couple of trees here today that I’ve just pruned for the next cycle. Both have had their tops restrained by tip pruning while the lower branches have been allowed to run.

The first one is a malus which I posted back in August when it was in its beautiful autumnal red. Today its before and after pruning photos. The wire will only need to be there for perhaps 4 or 5 weeks and in 6 or 8 weeks will look like the first photo again.

All that growth builds the trunk and primary branches developing taper and proportion. As you can see I’m happy to leave the top of the tree to be developed when it is the right time; that can always be done easily but if the lower branches aren’t developed now, then later is generally not an available option.

This one is a corky bark elm and has gotten pretty wild. Once again the top of the tree has been clipped to maintain the fine branches and the lower growth allowed to run. Building trunk mass over the years and keeping a tree in a presentable shape can be a slow process. 

And here it is after a good tidy up. Not too much wire in use and the foliage pads have had a good pinching to open them out and let the light in; ready to go again. If I was interested in further developing fine branches now would be a time for total defoliation. Leaving the leaves in place is more likely to result in new individual terminal growth, but that’s ok for a repetition of this cycle.
On my place I have a few big eucalypt trees and November is like another season here – we call it ‘bark’, because that’s when the trees shed their bark and generally make a real mess for a month. Well they’ve started and the first thing to get shed was a big paper wasp nest. I don’t know that I’ve seen one quite this big before and am very pleased I wasn’t around when it fell.


Monday, 13 October 2014

Post 177 Test tiles from glaze trial no 9

In my last glaze trial I continued my hunt for the 'perfect browns'. I started with a limited number of recipes that I liked from trial no 7 and then made a number of minor changes. Over previous trials the strategy has been  to bracket the inter-relationships between the colourants and then in this trial to test the fine detail. It is a valuable process and after a while you get to more deeply understand the colour impact of any one colourant and then the interactions between them.

 The base glazes I used have been described previously in Post 30 and Post 32. Those posts were over 2 years ago and this trial is testament to the value in finding a useful base and sticking with it.

 In each of the following pictures I have include the tile that was the starting point for the series - usually of 4 variations. The final picture is of a blue series where the same process was followed.
For the browns the colourants are generally combinations of Zinc and Chrome, Red IO and Yellow ochre and Cobalt. I haven't used Manganese. I find with my bases that it produces a muddy colour without much life. There is an interesting difference in the iron oxides. The RIO seems to impart an olive tone at low concentrations through to a yellow brown at higher, while the yellow ochre gives more of the red brown tones. So 4%YO and 1%RIO will be entirely different from 1%YO and 4%RIO.
I just added up all the recipes I've trialled to date and it comes to 622. That's 9 firings and 622 test tiles.I'm just starting to be able to predict an outcome, but always surprised at the result.


Now I've got 18 pots to glaze from the last bisque firing and will be using a number of these new formulations for the trial.

Wednesday, 8 October 2014

Post 176 Latest bisque firing

I powered up the furnace this week and now have some work in front of me.
The haul came to 18 pots.

You wouldn't know it but there is a mix of clays here or at least exact formulations. My supplier of the YG clay decided to change the coulourant from a yellow iron oxide to the red. While the raw clay has a different colour (pink rather than yellow) the bisque is the same and the finished vitrified ceramic should also be a similar buff colour. I'm hoping that the RIO colourant does not have the same fluxing effect and pot breakage that came with it in the RGH product when the formulation colourant changed there.

I have three of my new bowed wall rectangular pots, with varying degrees of rounded to sharp corners and three of a new oval with convex walls. There are also two nice little semi cascade pots in there and then a buch of new shohins. All the little loose pieces of clay in the pots are props to be used in the glaze firing. The depth of field effect in the photo is courtesy the gaussian blur filter in photoshop; neat.

In a couple of weeks I'm booked for a pot making demo at one of our local bonsai associations and was keen to be able to take a few pots along. I also wanted a pot I can show in the raw, bisque and finished state to show how it changes. I'm planning on making one of the ovals so will now be set for each stage.

The pots can to a degree be stacked in the bisque firing that is not possible in glaze firing so these pots probably represent two glaze firings coming up. My latest glaze test - number 9 in the series - has produced some nice new brown variants that I'm keen to try out.