Sunday, April 5, 2015

A Couple of "WOW" Bonsai Pots from the Kiln

I'd just opened the kiln from the previous post where I'd loaded it up with a hard to fit moon/cascade pot.
 
What a beautiful surprise.
 
I'd made a pot without a drainage hole for a willow that was always drying out and wouldn't perhaps survive much longer without continual access to at least some water on the bottom of the pot.(albeit through a drainage layer)


My daughters first reaction was "it looks like a pond".  It'd be almost a shame to cover up that beautiful coloured shiny glaze on the bottom.  Perhaps a few strategically placed stones above the drainage layer and some water may well create that illusion.  It will be interesting to see what happens to it.
The pot needed to have slits along the sides to enable a little water to drain out when it got to a certain height. While a small fissure type gap would have done, I think I overdid it with the slits I made on it.  However they don't look out of place in the whole scheme of things.
This is a one of a kind pot......the remains of two glazes were mixed together to make enough for this one. A little too much flux meant the glaze ran beautifully, but also ran down the outside onto the shelf.  It adds to the watery flowing nature of the pot. 
 
I wont hesitate to keep it if it doesn't suit the willows owner!
 
The other "WOW", or should I perhaps say "SIGH OF RELIEF" was from that crescent that had been tucked away on the bottom and surrounded by other conventionally shaped bonsai pots.
 
My worst fear was that the top would slump right down in the high glazing temperature and end up flat on the kiln shelf.   But it didn't happen........I feel the pot has a beautiful shape!

The owner to be of this crescent was very happy with it, as was I.  The challenge ahead will be to make one or two more with that same "sweep" shape. 
 
Overall, this firing was a success, and more importantly, I learned a little more......
 
Contact me on howimakebonsaipots@gmail.com, opinions and comments are most welcome.
 

Wednesday, April 1, 2015

LOADING THE KILN WITH AN AWKWARD SHAPE BONSAI CRESCENT

One of the challenges of loading up a kiln for a glaze firing is making sure you can fit as much as possible into it with the little space available.

This load has a larger crescent shape in it.  It takes up just over half the height of the kiln and has an overhang that doesn't really allow a kiln shelf to be placed lower down.  Well.....not normally.
Here's the sequence I loaded it in. 


 


A few more pots were nestled underneath the bottom curve with maybe 2 or 3cm clearance.

Here you see the awkwardness of the shape.  There was just enough space along the sides of this crescent to ease in a half shelf.  I wasn't quite happy about the clearance from the shelf edge to the side of it, but if it slumps a little in the high temperature, then at least the shelf is going to stop it a little.  The back of it is reasonably close to the side kiln elements as usually I try and keep pots about 1cm away.
Usually when you place the kiln shelves, you make sure to have an even gap around the edge to let the air/heat circulate evenly, but this was as even as I could manage to get this one.
I squeezed in 4 pots on the layer above the crescent, and another half shelf with two on it.

There is quite a bit of wasted space in this load as I would usually put another half shelf in but the top of that crescent made it too awkward.

Its all closed up now and is quite happily firing away into the night.........now comes the long wait until I can open it up and see how some of these glazes turned out........fingers crossed!

Hopefully one or two of these will end up on my POTS FOR SALE page in the next week or two.

Contact me on howimakebonsaipots@gmail.com, any opinions or comments are most welcome.






Sunday, February 15, 2015

LOOKS LIKE THE KILN IS OVER FIRING

Recently I purchased some large cones used to check the temperature the kiln is firing at.  Because I have a kiln that uses a kiln sitter and doesn't have a temperature controller or a thermocouple, I am relying heavily on the little mini cone that bends when it reaches a certain temperature to turn off the kiln.

I've had my suspicions that my old sitter kiln may be firing higher than what I wanted it too. Some of my glazes had been starting to run a little too much, it never used to be too much of an issue.

I had the opportunity to purchase a used portable thermometer that could be used to measure temperatures up to 1300degrees Celcius.  While it needed the end replaced, it was still useable and appeared to have a reasonably accurate temperature.

Firstly the end is placed in the kiln peephole while the kiln was firing and after a fairly short wait it comes up with the temperature at the end of the wire.
(just a demo to show how it works, kiln already emptied)
The kiln had been loaded and had been on for 8 hours already.  When I put the probe in it came right up to 1094degrees Celcius.  Because this was a bisque firing I only wanted it to go to cone 04 (approx. 1000degrees Celcius)  Already it was 100 degrees over according to this thermometer.   The kiln turned off shortly after.
This is a pic of the little 04 cone that bends when it reaches the correct temperature.  When it bends the middle bar falls down when triggers the cut  off switch. The number of the cone correlates to the temperature it bends at.
I thought with end probe being a little burnt off that perhaps it wasn't that accurate anyway.
However when I unloaded the kiln I found that the two large o4 cones that had been sitting on the top and bottom shelf had well and truly fallen and were resting on the kiln shelf.  This had confirmed the over firing.
 A closer look at the fallen 04 cone that was on the top shelf

Normally the cone wouldn't bend right over to touch the shelf.  Unfortunately I don't have any 03 cones to see just how far the temperature really did get.

The pots from this load all looked a little duller in colour than the normal pinky bisque shade.  Just slightly though.
It will be interesting to see how well they absorb the glaze. I'm also wondering just how long this has been happening as usually I don't put cones on the shelves to check.
The large crescent that I talked about in the last blog was bisque fired with this load as well.
The top overhang did drop quite a bit, I had a feeling it might.  It will be interesting to see how much more it drops in the final glaze firing where the temperature is another 260-80 degrees above the bisque.

The lesson I've learned is to regularly check the firing temperatures with cones on the shelves.  Not too important with the glaze firing as most of my clays/glazes will withstand a little higher temperature without any negative affects, but the bisque firing temperature can affect how much glaze can be absorbed as the clay has already started to vitrify and is not so porous.

Things would be much easier if I had a new kiln with a temperature controller and a thermocouple, then I'd know exactly at a glance what was going on.  It looks like I'll have to sell a heap of bonsai pots to afford one of those!

Contact me on howimakebonsaipots@gmail.com,  any opinions or comments are most welcome.
 

Tuesday, January 27, 2015

MY FIRST ATTEMPT AT A LARGER MOON/CRESCENT BONSAI POT - HELP!....I NEED FEEDBACK.

Here 'tis.
Its dimensions are: 37cm high x 43cm long x 9cm deep(at lowest point)  30cm wide at bottom
or in inches:  14inches high x 17inches long x 3.5inches deep(at lowest point)  12 inches wide at bottom.                       
Someone a few months ago had asked if I could make one approx. 40cm high and long.  Unfortunately I think this will be as large as I can make without having an extra pair of hands to help handle the sometimes awkward process.
After a bit of head scratching, hunting and innovation I managed to make a larger crescent bonsai pot.  The final shape was a little hit and miss as I had to more or less "hang" it upside down until it got to the leather hard stage.
Its supported by a stick and two big globs of clay at each end.  Its the only way I could think of for supporting the convex part of the pot.  I leaned a piece of gib offcut against the outer wall as well.  Even though its leather hard, there is a lot of stress on that curve. Gravity is saying it should be bending down, and I'm saying "stay up there until you're dry!

There is only a small flat area on the bottom.  I've added lots of small holes instead of large drainage holes.  When I remove the support I'll add one large hole in the middle.
This is the view looking into it.  Its not the view that the pot would be displayed at, so I'm not too bothered about the excess clay on the right side.
  I have a few questions and would value the opinion of some more experienced bonsai enthusiasts. Especially those that have used this type of pot before and have come across problems.


1.    Does it look deep enough for a reasonable sized  trees rootball?


2     I'm worried that it may tip backwards unless there's more weight put on  the front end, (addition of a rock at the front to counterbalance the weight of the top curve?


3.    I haven't added feet as I feel it would spoil the sweeping flick shape. I know it needs to be off the ground slightly for drainage, would a few pebbles/stones placed underneath be enough?


4.    The drainage holes in the bottom, would these small holes and one larger in the middle be enough?


5.    What do you think of the proportions, should it be higher and less long, or longer and more sleek looking?


I personally am really pleased with how its turned out so far, but still a long way to go before its finished.  A bisque and glaze firing to get through first.  Which makes me wonder if I am going to need to support the upper part of the pot in the kiln as well, especially in the glaze firing when the clay gets quite soft at the higher temperatures..... perhaps someone can help out with a suggestion to that wee problem.

Will keep you posted on how she turns out.  Fingers crossed!!

Friday, January 16, 2015

A FEW MORE BONSAI POTS FROM THE LATEST FIRING

There had been a few bonsai pots sitting on the shelf unfinished for the last couple of months.  Mainly because I had decided to play around with the recipe for the ivory crackled pots.

3/4 of this small load was the result of  "cross your fingers and hope it works out!"

I'll sort through them over the next day or two and put some of them on my "Bonsai Pots for Sale" page
 These were the pots that came out.  I was really pleased with them, especially the large round one on the end.
 The bottom of this pot was quite dark, as I realized when I applied the wash to it.  A lot of the darkness fired out, but the lower area is still quite dark compared to the middle and top.

 This pot is one that I've labelled as special.  Sometimes a pot will come out of the kiln and it has that something special. Nothing you can pin point in words, it just has that X factor.  Everything has come together.  This one is quite honey coloured.  The crackling is just amazing on it.  I suspect it may be a "keeper", may have to think about it for a day or two.
 This one is a little lighter in colour and the crackles are quite vertical, a feminine type pot.
 Instead of making a crackled texture on this one, I decided to accentuate the throwing rings on the outside.  The wash picked up most of them, but I'll try making deeper grooves with either my fingers or the end of a chop stick to make them stand out a little more on the next one.


 This pot reminds me a little of a light timber floor finish,  very nice though, and a little different.
 This was the corner of the pot in the previous post (wasp nest under pot)with the attempted wasp nest on it.  I unfortunately had to scrape it off before firing (in case it melted), but you can see where a little bit that remained has melted into the pot (the lighter colour in the corner)
 This was the pot that I'd made from a mold that had been sitting in the shed for ages.  To be honest....there was no enjoyment in making it.  I knew how it was going to turn out shape wise, there was no room for creativity, apart from the opportunity to play around with a glaze.  All I can say about it is that its finished and out of the way!
 Another one of those special pots......Its 43cm diameter, round and has the most beautiful crackled texture. The pictures don't do it justice.  Its one of those pots that you just go "wow" when you see it.  It looks like its been around for hundreds of years, through all sorts of weather etc.  Perhaps this one is a "keeper" as well.

It's funny how you can get so attached to the pots you make,  its a bit like having a small seedling that you've nursed along for many years and now its a beautiful looking bonsai tree. You would never dream of selling or giving it away.  The same goes for some pots....it starts as a lump of clay, you shape it, carefully and slowly let it dry, you then bisque fire it, then you have to decide how to finish it before the final glaze firing.  All along you may have an idea of what you want the finished pot to look like, just the same as you have an idea in your head of what you eventually want your mature bonsai to look like.  Granted, it doesn't take years, but the same love, care and attention goes into it.
 Enough waffling I think. The glass of water is for me.....it gets stinking hot in the garage when the sun comes out, like sitting in an oven at times, even with the doors open.  Such is the weather down here in Southland, the best in New Zealand I have to say.  

Don't forget to look in my Bonsai Pots for Sale page over the next few days, as I'll be updating it with more new pots.