Thursday, 27 December 2012

Post 64 Some pots from my collection

Another Christmas has come and gone and this will be the first for many years that I didn't score a new bonsai pot for a present. For a long time that has been my standard request for and ABC event ( aniversary, birthday, Christmas). At least I can't be accused of being boring anymore- well at least not for that reason.

The motivation for getting into making my own pots was about getting bigger and better for less. I didn't know a lot about pots before making them myself and I think many enthusiasts would be the same.

Most people at some point in their lives will have bought ceramic tiles, for a reno job, a new house or simply repairs. If you reflect on that purchase you might recall the information available about the different types and classes of tiles for different applications and what they may be exposed to.
 There is a clear distinction between non-vitreous, semi vitreous and vitreous tiles. This classifcation has much to do with the type of clay and the firing cycle it may have been matured to. You would chose between them depending on whether they were to be located inside or out, on the floor or the wall etc. There is a clear quality, service capability and price relationship at work with ceramic tiles and you get what you pay for.

Such a pity then that the same level of information is generally not available when purchasing bonsai pots, beacuse the same considerations should apply; what sort of clay was a pot made of, how was it fired and how will it perform in service.

This pot for example is a nice shaped little unglazed oval pot about 370mm long. Before taking the picture I gave it a vigorous wipe down with a damp cloth and then let it dry, no brushing. The pot has been out in the weather for years. It has provided good service but before even thinking about using it for a displayed tree some serious work would be needed. Actually now I wouldn't even think about it. It's just a grow pot and I'm just keeping it long enough until I have one of my own to take its place..

As you see there is a whitish deposit on the surface of the pot. This might be lime scale but I have others of a different origin which do not suffer from that so I am more inclined  to think it is efflorescence, the migration of slightly soluble salts from within the ceramic material to the surface; the sort of thing often seen on new brickwork. This is a reflection on the quality of the original clay body and what may have been added to it for various reasons. I suspect this is a low fired earthenware ceramic material which in tile terms is non or semi vitrified, which gives it a level of porosity that allows water to move through the pot wall and carry salts to the surface. That porosity also allows and supports unattractive biological patina to grow on the pot, futher diffusing the appearance and colour. Unfortunately in the absence of information about where it came from, how it was made and its qualities you don't know if the pots you buy will look like this one in a few years time.

I now know you can tell a low fired pot from a high fired pot by the bell test. Support the pot on a finger through a drainage hole and wrap the pot with a knuckle - to get anywhere from a thunk, to a ping to a resonant bell.  If you don't want a pot that looks like this one then if they don't ring like a bell don't buy them. A drop of moisture on the pot wall will also help you understand its porosity, a key influence on future appearance.
Knowing what I know now and having made and used pots in both earthenware and stoneware, I would never ever buy an earthenware pot again. If it wasn't stoneware I wouldn't touch it no matter what, I'd rather use a plastic pot.

Glazed pots are a different challenge to assess.

 This pot is a shohin sized glazed oval. It also is a few years old and has spent all that time out in the weather. When I bought it the glaze was a most attractive high gloss and you can see where it has run in the firing to give a gradation in colour under the rim. The picture is a truthful illustration of its current state. The glaze now looks like it's been sandblasted to remove the gloss leaving a very dull surface appearance. Once I just thought that a glazed ceramic surface was glasslike and forever. Now I understand the chemistry and that is only so under certain circumstances.

Most folks will at some time in their lives have been in a limestone cave - stalactites and stalagmites etc. They take a long time to get like that and have come about through dissolved limestone redepositing from drops of calcuim carbonite rich water evaporating and leaving the crystaline material behind. That's why the mites and tites sparkle. But of course how did the limestone dissolve in the first place. Well easy really; as rain falls carbon dioxide in the atmosphere dissolves in the rain, turing it into dilute soda water, otherwise known as carbonic acid. Dilute acid will also attack the surface of a glaze, if it is not correctly balanced and stable. Glazes which are used on ceramics for food service by professional suppliers will be formulated to be resistant to attack by dilute acidic food materials; it is possible and simple enough.

So back to the pot. The little blue / green pot glaze is what I call a showroom glaze; looks great in the showroom, but never ever take it out in the weather or it will wash off! Yes it really does start to wash off over time and it's the surface, the reason you bought the pot,  that goes first. I've got a few pots like this, how about you? This is a really difficult issues to deal with at purchase time. The only way to beat it is to know where your pot comes from and how it has been made.

If you are interested in how your unglazed and glazed pots will look after a few years out in the weather and your retail pot supplier offers no information about their pots other than price, then pretend you are buying ceramic tiles and ask more questions. This is why I now make my own but there was a time when I decided to go right up market; next time I'll show you my two Tokonome pots.

Thursday, 20 December 2012

Post 63 Ceramic dovetail

We all know about timber dovetails, those traditional little reverse wedge shapes used to connect pieces of timber in a really strong joint. Dovetails in drawers continue to be the hallmark of a well built and valueable piece of furniture.

But what about stone or ceramic. I got thinking about this recently when a pot came out of a bisque firing with a crack in the side wall. This is only the second time this has happened and it is a bit annoying. After having invested the time and energy to get it here it would be disappointing to throw it away, but to continue to go to a glaze firing would amost certainly result in the crack opening up and rendering the pot almost un-usable. I've looked for but haven't found an approach on the net about how to repair it for a reasonable glaze firing result. If anyone has an answer I'd love to hear it.

I think I know how the crack happened and how to avoid it in future; a question of differential drying stresses.

 In this photo the crack is at about 7 oclock, just left of centre on the rim. Here is a closeup. It would be a nice pot and I was making it for a japanese box forest.

So how to fix it. There are well established practicesboth new and old for repairing broken ceramics, but none of those methods will survive the changes and temperature of firing to maturity. What ever you use has to contract 6 or 7% with the body of the pot, retain the pressure on the crack faces and not burn up at 1230C.

The ancients used metal  'clamps' and dowels to join masonry in the days before reliable cement / mortar technology. The Greeks used pieces of iron set in holes in the masonry around which molten lead was poured to secure the joint, as above.

This one is a double dovetail or bowtie from Egypt at the ancient temple of Dendera

This picture is of the Temple of Apollo at Delphi in Greece and on the foundation blocks you can see the interconnecting iron clamps - installed like staples to keep the blocks together. This was an early technology to earthquake proof a building.

 And for the students of history can anyone tell me what this picture is all about. Well in the chaos of the post Roman world when iron production went into disarray you had to get it wherever you could. So the ancient world's ruins became both stone quarry and iron mine, where it was sometimes easier (cheaper?)  to chisel through the stones in a wall and extract the iron clamp than source freshly produced material.

I do remember too, though could not find a picture, of the stonework on Fort Denison in Sydney Harbour. As I recall stone bowtie joiners were used there to tie together the monumental stonework on the wall of the big gun emplacements. Perhaps this was commonly used in 18th and early 19th C defensive military stonework. If anyone has got a picture of this please send it to me and I'll post it.

 Well all very interesting indeed and mostly well before the time of bonsai so not really relevant. I agree of course.  
But with all that perhaps there is some precedent for me to fix my pot with a bowtie double dovetail clamp made of the same material as the pot.

So on the inside of the pot I've placed a bowtie that is about 2/3s of the wall depth and also drilled a small hole at the limit of the crack to stop propagation. Bisqued clay is nicely workable. Before firing I'll sprinkle a little galze in the base of the bowtie recess and around the join to secure it in position, then glaze right over the top both inside and outside. The crack may still be apparent, but after reaching maturity it will be totally stable and with luck the wall will now not gap open. Time will tell.

That's as far as I've got on this one and will now have to wait for the next firing opportunity. Speaking of production disarray I'm doing a few little renovations in my workshop at the moment and both pot making and firing is in total disarray!

This will likely be my last post for 2012. Season's greetings to one and all.

Sunday, 16 December 2012

Post 62 A branch hidden may be a branch wasted

I have mentioned previously the value I get out of having one of my trees in the house on rotation. Each one gets a turn for a week and I get to look at it every time I go backwards and forwards. It is always hard to find the flaws in your own trees, but then quite surprising some times what you can see when there is only one to look at.

This willowleaf ficus (Nerifolia) has been styled with a well defined branch structure which is a little different from the umbrella canopy style you often see it in. The second branch connects to the trunk on the back of the trunk. Up until now it has been oriented to be pretty much in a sight line directly in line with the trunk, away from the viewer. The foliage pad can be seen and is arranged to provide the background depth to the tree. The prominent space between the left hand branches is too prominent. So why not fill the space and at the same time get some value out of that second rearward facing branch.

The next picture shows the temporary restraint in place to set the branch in a new position. This fills the space a little, provides some visibility of the branch and retains the background foliage pad for depth.

Courtesy of a little photoshopping I can take out the restrainer to more clearly see the final result. It will be a matter of viewing height but a possible problem this creates is the close alignment of the rear branch with the first right-hand branch. This can be resloved at a later stage with a little 'S' bend in the rear branch to lower the visible part by about 10mm to get a result.

I like the way taking a picture of a tree  and thus compressing it into two dimensions sometimes makes it easier to take a uncompromising clinical view about styling You get to see it in a different way. A photo shop like tool is also a good way to move branches around and experiment before you take irreversable steps.

Thursday, 13 December 2012

Post 61 More clay formulation tests

This is going to be a little technical for most folks but for the ceramics affectionados it might carry some interest.

Some time ago I ran a series of tests adding various materials to the clay body I have been using to evaluate the impact on deformation, shrinkage and porosity. Nothing stood out as a winner which was good enough to go to the trouble of adding and combining a dry material to the clay.
The best result came from the addition of Kaolin, but it wasn't good enough to take up the option.

A little further research suggested two further alternative prospects. One is like a calcined version of Kaolin called Molochite and the other is a calcined Alumina. Calcination drives out all forms of water both free and molecular. The composition of Molochite is principally silicon and aluminium oxides and the Alumina clearly just aluminium oxide.

So I designed as set of test samples using these materials at concentrations up to 20% using two Clayworks stoneware bodies - RGH and CTS.

 The photograph above shows the stack of 12 deformation test samples, stacked in order of performance. The RGH samples - darker colour - performed less favourably to the CTS.
CTS also showed less shrinkage which was consistent with the deformation characteristic.
Unfortunately this superior performance was achieved it seems, by the action of the additives in elevating the vitrification temperature of the clay body, demonstrated by relatively poor levels of permeability at increasing levels of the additives. The CTS also had an unsatisfactory permeability when fired to the same schedule as the RGH.

Taking the clay to vitrification temperature is all about achieving impermeability and so to include a refractory additive which might improve the physical dimensional characteristics (stability) at the cost of vitrification and permeadility would be going in the wrong direction. That's likely to be what the Chinese mass bonsai pot market producers seem to be doing. This might be ok if you are making a sculptural object where the dimensional and shrinkage properties have a higher priority but for a bonsai container exposed to the elements it's the wrong end of the compromise stick.

Interesting as the idea of an additive was it's looking like a dead end. Besides incorporating a dry powder into a clay body in sufficient quantity, up to 20%, would be a huge pain in the asp so I'm pleased not to have found a compelling reason to do it. The answer might well be the simple matter of testing just how much heat work is needed to achieve vitrification; where is the tipping point, the elbow in the curve. I'll just have to fire up the test kiln and run some different firing schedules to learn a little more.

Monday, 10 December 2012

Post 60 Moonrock

In the last glaze firing I also fired my latest root over rock, rock; the moonrock.

The colour of the clay itself when fired is quite a good stony buff colour and although once fired the stoneware is as good as impervioue to moisture, I still wanted to put a layer of glaze on it.

The glaze I used is one formulated with yellow ochre  as the colourant which for some reason offers a few more of the brighter red tones than the Red Iron Oxide which at the same level goes more brown.

Not wanting to mix up a large quantity of glaze to dip it, I painted the glaze on, which wasn't easy with all that surface texture. That said I could have used a little more glaze. Even with glazes which are formulated to produce a matte surface, where it is applied thinly it will often darken in tone towards the browns and develop a more shiny surface. So there is a little more shine here than I wanted but all those nooks and crannies will soon catch a little patina. I've got it out in the weather now, just waiting for my tube planted ficus to develop a little more this season.

Tuesday, 4 December 2012

Post 59 Another 4 new pots

Another glaze firing done and some happy results. The kiln gods have smiled again for now. That's a bit like that old one about the harder you work the luckier you get, but I might have said that before!

This first one is Pot 34 a short Taraibune oval at 425 x 310 x 78. The glaze is a light blue tone applied to simulate a little patina. A nice size and very useful pot.

This is my original Wasen design again, Pot 36 with a finished size of 407 x 300 x 84. You might recall some time ago - Post 46 in mid October - I tried something new in a glaze firing and as a direct result caused a Wasen oval pot with the same glaze as this one, to be badly deformed. If I'd really thought about it, the result was predictable, but not at the time. Bob offered to take it off my hands for the feight cost but I relented and decided to keep it where I could see it just to be reminded, about fallibility and the danger of hubris. Speaking of which I put a tree in that pot and unless you really look for it you would hardly notice the flaw. Imperfect perfection - the power of wabi sabi. The antidote might be wearing off.
So here is Pot 36 in the same glaze - light green tones breaking beige and in great shape.

To show the flexibilty of mould made pots here is a Wasen with a squared rim flange; Pot 37 at 412 x 300 x 84. Just a small change but a different look. The picture doesn't do the glaze justice and sometimes with digital photography true colour rendering is elusive. Suffice to say it is formulated as a cream beige glaze but the different depths of application break the surface and colour. There are a number of stoney earthen colours here that make for a great composition. It looks like it's been carved from a piece of stone and buffed. I don't think I can part with this one, at least not before trying to make another one like it.

And finally for this firing we have Pot 39 which is a Tenmasen rectangular pot at 407 x 300 x 84, in a glaze used before too. But it makes such an interesting surface that it's hard to resist using it, making a very handsome pot.

So all in all a good result; all nice additions to a collection.

Sunday, 2 December 2012

Post 58 Bekabune

The Bekabune is another traditional inshore Japanee fishing vessel. This picture from Douglas Brooks' excellent website shows one he made as an apprentice in Japan. The craftsmanship is exceptional. This museum quality build was done entirely with hand tools only - now that's dedication.

The edge joined planks and flush sides of the craft offer enough similarity (never mind the pointy end) to attach the name to my latest pot model.

I made the mould a few weeks ago and this is now the first one produced, pictured full frontal and three quarters, wet clay yet to dry out.

Final fired dimensions for the pot will be about  340 x 260 x 55, so it's a useful intermediate size a little smaller than my other ovals, which are both a little over 400mm long.

In my first design for the pot I toyed with the idea of making it without the rim flange to give a very clean line. But I think the composition works, the proportions are sound and having incorporated the rim flange in the mould gives me the flexibility of making a pot without it. It would be more challenging to do it the other way around.
There are as usual with mould made pots, opportunities for post production alterteration to break the pattern. Things like setting the feet back slightly to break the line, changing the rim flange profile, outer or inner rim flange, wall planking or other textural detail and even pot height; one mould many pots.
It will be good to get a few of these down the line. I have a number of my trees in imported pots of unknown origin which are about this size and they are looking very ordinary. So it will be good to change them out and there will be a bunch of secondhanders on the sale table at the next exhibition.

I have a friend who refers to my kiln as 'the blast furnace' and suggests that every time I fire it his lights dim a little. Ha Ha. Well his lights should be doing just that today with 4 more pots in for glaze firing as well as my moonstone rock which I have glazed with what I'm hoping will be a super matte iron reddish brown glaze.

Wednesday, 28 November 2012

Post 57 Shohin Pot

Over the last month I've been working along in the background developing a couple of new models for pots. One of those is a Shohin sized pot and the other is a midsized oval. More on that one later, but for now I have some early shohins to post.

The shohin 'class' is of course bonsai that are normally less than 20 cm and it is a class that many enthusiasts specialise in. Shohin pots and pot selection for shihin bonsai pretty much follow the same conventions that apply to larger bonsai, although there may be a tendency for slightly brighter glazes.

So I was casting about for a design and was reluctant to just make a smaller version of a larger pot. I've always been attracted to neolithic pottery - ie. pre bronze age. There are some fantastic forms and decorative styles in different parts of the world. I borrowed a book from the library about the history of Chinese pottery and come across a circular bowl with a full skirt foot arrangement. It was dated from the 10th to 12th Century  BC and a beautiful piece of functional art. I didn't take a picture but did make a sketch. The rim flange had a beautiful curvature from above as well as below, a feature I wanted to capture.

I prefer oval over circular for pots and so after setting on dimensions for an oval adaption refined the proportions of the form of the sketch. It was then the usual path of positive model and casting a mould. The final finished pot length will be about 170 to 175 mm; it's 200mm wet.  Being such a small pot the whole process has been quite a bit easier but the mould drying time has been just as long and it's been sitting there for a couple of weeks.

But it's ready to use now and I've turned out the first few pots. These are all still 'hot off the press' and quite wet, as you can see.


This is the first one. Finished with nice smooth surfaces for a good glazed finish. I think I have made a pretty good replica spanning the millenium.  The lines are very 'classical', as in the original, and it could just as easily be of Greek origin.
My wife immediately ordered one - no drainage hole, fully glazed, for chocolates at Christmas!

The bottom of the pot is at the level where it necks in. I've been toying with the idea of a central front moongate type opening in the foot ring. It looks ok on photoshop so will no doubt try it out.

 This one is formed with surface that looks like it's cracked. A thin matte glaze or even simply a stain with the colour of old burnt terracotta might be good, to more closely replicate the original.

This one has an unfinished coiled surface finish.

And then just for fun a coule of real textured models. This one has a planked surface with small matching feet and the last one is shingled. I'm already planning on an antique bronze finish for the one above.

More news on the other new oval soon.

Monday, 26 November 2012

Post 56 Sunny Sunday

It can only be about 8 weeks ago that we threw a few sunflower seeds on the ground in the vege patch, it sure doesn't feel like it was any longer. They germinated in 2 days and were forming the flowers when the were 60cm high. I thought we must have had the minature ones; but they kept on going. At head height some have opened and others just keep on going.
They are SO bright they just put a smile on your face, no wonder Van Gough kept painting them.

 The bonsai have been moving fast too. This one is a Celtis that appeared in a root pruning post from back in August, with a final fan of roots about 150mm in diameter. It leapt out of the starting blocks in September and since then it's had an almost full defoliation, recovery  and yesterday another very thorough pruning. The fine branch structure is developing really well.

We have a display stand in the family room and there is always a tree in place, with a weekly rotation. I find this a very usefull way to assess what each tree may need to develop the style. You get to look at the tree critically, lots of times in the week when the only thing you have to do with it is to look at it . Having it on its own, at a particular height, without a distracting background almost always leads to some change - branch relative positioning, bulk, space, shape, movement etc etc.  The key to creating an illusion is seeing into the illusion we create.

Friday, 23 November 2012

Post 55 Pot Sales Launch

It is my pleasure to list 8 pots for sale on the Pot Sales page; for your consideration.
As a launch special the price of the first four pots purchased will be discounted 10% from the prices listed.

There are full details of each pot offered as well and payment and delivery arrangements on the page. If there are any clarifications needed or further questions I'm happy to correspond by email.

Happy Potter

Thursday, 22 November 2012

Post 54 New pots

As I said in the last post, 4 new pots are done and here to share today.

Each design and style demands its own little individual kit of shapers, formers, frames, bits and pieces. These have to be stored and labeled to get the right set for the right pot during making - I need to give them names to make sense of it all, which go beyond 'the rectangular one with the bead along the bottom' etc etc or drawing a picture on all the bits!
So also to share today are the names, inspired by the names of traditional Japanese inshore boats, I've given them to distinguish between them.

The first is the traditional style you will have seen before, the 'Tenmasen' style. It is quite formal in design and has a more masculine posture so the darker tones suit it well.
Pot 33. Finish is satin. Final dimensions are:  380 x 278 x 86

This one is the smaller rectangular pot you will have seen before but a little shorter. This particular one has a small internal rim flange. The simplicity of this design is quite appealing to many people, with the feet integrated into the pot walls and the 1in 5 inclination; the 'Sabani' pot.
Pot 29. Finish is satin. Final dimensions: 335 x 238 x 68
I've started making this one with a rim flange lately too and these are still coming through the 'pipeline'.

This is the one with the patinated antique look I mentioned in the last post. Quite a simple rectangular pot without detail ornamentation; the 'Kaisen' style. The glaze is nicely differntiated and quite matte, contributing to a weathered appearance of age.
Pot 32. Final dimensions:365 x 260 x 70

And the final one for this firing is  a blue/green oval 'Wasen' pot. This one has a rounded rim flange with grooved walls. The glaze breaks on changes in surface and glaze thickness, green where thinner and blue where thicker.
Pot 31. Finish is satin matte, final dimensions:406 x 297 x 83
I've made a couple of these recently with a squared rim flange as on the Tenmasen, which makes an interesting point of difference - coming soon.

Over coming days I will place these 4 pots and a few others on the sale page, for anyone who may be interested.

Tuesday, 20 November 2012

Post 53 Fire in the Hole

Well not exactly.  Certainly hot but not explosive.

 It's ok with the naked eye to look into the kiln when it's running at >1300C (2370F) but the camera didn't want to do it. Its hard to stay away when its happening, knowing what is going on in there! And its SO hot but you can stand right next to it.

The insulating capacity of the firebricks is amazing. Here I am holding the vent plug, just withdrawn. As you see the end of it is running at the kiln temperature but the part in my hand is only just warm. The secret is non conductive refractory materials with lots of air, making a very light material. It's actually quite soft too and can be cut and shaped with blunt knife.

Life and other demands have taken more than their fair share of my time in the last 2 weeks and I'm running behind where I'd like to be. It's been a challenge to find the 12 consecutive hours I need to be here during a firing.

But it is done now and I have 4 new pots cooling down. Through the just open door it looks like some great results. More glaze recipes not previously used on pots, with good differential  colouring. One looks like an ancient patinated surface which will be a great result. I just have to be patient and let them cool.

Tomorrow with luck I'll get the camera into action and will then have some pictures to post. With these four pots it's looking like I will have enough to open the shop and I'm looking forward to populating the Sale page with some pots for sale. Very close now and just in time for Christmas.

Tuesday, 13 November 2012

Post 52 Bisque, moonrock and defoliation

I had a good firing on Sunday.

 The good news is no displaced feet so the extra effort of recent times to make sure the bond is a good one has paid off. Now on to glazing, the real fun.

In one of my idle monments lately, or perhaps the idle moment, I threw a little clay into making another root over rock, rock. This one is going to have to be called a moon rock after all the mini craters over the surface. I guess this makes it look a bit volcanic too. I'm going to glaze this one with a very matte glaze, when I can get some kiln space freed up, with a mix of colouration for better natural simulation.

 The same positioning issue arises here as with a bonsai - just which is the front. I think this is and the next shot is from the 'side'.

My bonsai starting and propagation has slowed right down over the last couple of years so I've had no stock to call on.  This season a friend gave me some cuttings of a Port Jackson fig and also a South African variety and so I've set them up growing in tubes. With the warmer weather they have got a wriggle on so I might be able to set them up next growing season. No rush to get this rock finished.

On the bonsai front the trees are running well. My focus this season has been to get some vigour and mass into the lower branches of some of my deciduous trees. To do that I've tried to progressively suppress the apical dominance which puts the energy into the top and tends to want to leave everything else behind.

This Chinese Elm is a good example.

At the top of the tree I've fully defoliated and pruned the branches and after 10 days or so I now have two or three fresh shoots on all the secondry branches. This will give fine branches to dome out the top with more and hence smaller leaves.
Further down the tree where I've just wanted it to hold its position I've just pruned. The tree's usual response to this is to shoot at only the single outermost bud. As this happens they are tipped.
And then finally further down the tree some of the spring growth has been allowed to grow, to develop more mass in the lower branches. They have a little further to go before coming off. It's time now to do a little wiring of these new branches, but making sure to keep the terminals pointing upwards.
Next step after a little more growth and  the new shoots harden off will be a complete prune and defoliation.

Now I have to go and select some glazes:

Thursday, 8 November 2012

Post 51 Bisque load

Pot drying has gone well and a final touchup for the next 5 done; now ready and loaded for a bisque firing.

Each of these pots are quite different. The one in the middle is a new shape; a super short version of my big tub oval, and second from the bottom is one of the classic ovals with a heavily horizontally textured drum section.

The other pieces you can see are various bibs and bobs, tools, templates, test sections and some props.

I need to be around all day - 12 hrs for the firing and it's looking like Saturday will be the next opportunity. Better get the kiln god ready!
If you don't know about them they are worth a quick Google. What happens after you close the door and hit the switch are in the hands of the gods so a little recognition can't hurt, or so the story goes. Sounds like one of those things that if you start then you can never stop!

Sunday, 4 November 2012

Post 50 Garden Visitors

We've had a couple of visitors to the garden recently that I though I'd share.

The first was a nice llittle carpet python that cruised along looking in the windows. It's mating season for them at the moment and there have be lots of sightings around in broad daylight. This one was about 2.5 meters long and in beautiful condition -  a beautiful creature, showing off its carpet pattern well. The cat was inside the glass looking out at the time and has gone very twitchy ever since.

The other visitor is a member of a community we hear more often that see. They usually sleep all day and you wouldn't know they are up there in the trees looking down. At night time, at this time of year, they tear around the trees at night with the males calling for and generally in hot pursuit of a mate.

They are amazing climbers and the trees they prefer are 'scribbly' bark eucalypts which have a very smooth bark. An insect gets under the bark and leaves a scribbly mark - hence the name.
We've got some pretty big ones at our place and they've all got Koala scratches on them - evidence of their climbing.

This tree is about 800mm diameter at 1 meter off the ground. If you zoom in you will see both the scribbly marks and the Koala scratches. Imagine how they have to hug these things to climb and not a crack or crevice in sight - gives a whole new meaning to free climbing.

Friday, 2 November 2012

Post 49 Another day another pot

I've had some time on my hands recently and have used it to punch out a few pots. I'm not yet attempting to make more than one a day; after all I'm not looking for another full time job! Where does the time go. I'm getting quicker but there's no compromise on quality.

The routine for mould made pots takes up to an hour to prep the clay and get it in the mould with the inside surface completed. I like to finish the inside surface so that it is smooth, blemish free and nicely curved. That done then there is work done to make the feet. I make these separately and attach later. This gives flexibility to modify the design and use different geometry. I did find also early on that with the feet integrated into the mould it was difficult to get a good result.

It takes about 6 hours before the pot is released by the mould and ready for post mould alteration or shaping. In the mean time there are other things to be done with other drying pots which has turned my mind to the 'production system' or the 'pipeline'. More on that later.

Post mould shaping, conditioning and feet attachment takes up to another hour and then it is set aside to dry for up to three weeks. Half way through that time when the clay is leather hard it is a final opportunity to correct anything that needs it. Sometime I use a small wood plane to make more than cosmetic adjustments to the style. It's a good time to do these things when the clay is more timber like in texture and less sensitive to contact damage. Finally when bone dry is when the preparation for bisque firing is done. This may involve a little sanding or scraping to get flat surfaces flat, curves without flat spots and radiused edges where they may be needed, like on the rim. At this point it demands some care in handling. So overall preconditioning for bisque firing takes perhaps another hour.

After bisque firing the pot can still be sanded reasonably easily and is a good time to make sure all four feet touch the ground. There is generally almost no movement in the clay during bisque firing. And then it is a matter of mix the glaze, wash the pot, mask surfaces to remain unglazed and apply the glaze. There goes another hour.

That's about 4 hours direct hands on the pot, not to mention working on basic common infrastructure, materials, kiln loading / unloading, housekeeping etc etc. The reason I've been thinking more about this is to work out the size of the pipeline. Now if I want to make 100 pots a year, two or three a week, that's going to take a little time each week. Then what about space. If they need to dry for three weeks, then to make 100 a year, means I will always have 6 or 7 or 8 pots drying, and the same number bisqued waiting to glaze.

With that thought and drying pots sitting on all sorts of horisontal surfaces, I set about for a tidy up and shelf build. The kids stuff in boxes got moved to the departure lounge (I hope) - ie the shed out the back.
The shelves -nothing fancy but just something adequate. Here you can see the result of my work, and 6 drying bagged pots, not to mention a couple of moulds. That esky is next in my sights!

The other shelf has a sliding door drying cupboard, storage space for bisqued and finished pots, glaze materials, scales etc etc. I don't know why my wife suggests I'm taking over the garage.

So yes where was I; more pots. Last one made yesterday was No 37 and last one glazed and posted here was No 26. The pipeline is full and there will be a few pots for sale soon.

Tuesday, 30 October 2012

Post 48 New toy

What do all good marketers say - "buy on emotion and defend on logic". You see I've bought a small kiln. Now I'm a two kiln potter!!!

So my defence of this latest purchase is the intrinsic value I will get out of being able to do small scale firings for glaze, firing schedule and clay body testing. Fire a small number of samples, evaluate and test again without having to wait for the bigger kiln to have a nearly load ready or otherwise fire underloaded. This little one is certainly too small to fire all but the smallest bonsai pots. And how did I get it past the Senate Estimates Committee - well what all good long serving workers would do - make a claim on prior unrealised accrued benefits. It worked for me.

It's a Woodrow Minifire kiln with a firebox that is only 300 x 300 x 150. It comes with its own controller and runs on 240v so just plugs straight into a regular wall socket. At 1800 watts it's like running a big room heater for the duration of the firing, except the 'room' is just that little firebox. No wonder it can get up to 1280C in there.

In the picture you can see I've mounted it on a small trolley so it can be wheeled away and stored, works well. It only weighs 25 kilos but there's just no way to pick it up. That little white plug on the top is the vent.

It's had it's first test firing - I took those clay body additive test samples of Post 47 through the glaze firing schedule. The little programmable controller works a treat.