Tuesday, June 21, 2011

The Moon went all funny! Hick! Bowls, glazes, and electrical wizardry!

Many a person weaving their way home from the pub late on a starry night has difficulty counting the number of moons in the sky.  Of course it is not their fault.... It would help if the moon stayed still, which is doesn't... And it would certainly help if it remained the colour of a good Stilton cheese.  After all, cheese and Guiness, Lager or Stout, is a match made in heaven!  So the moon should be the colour of cheese, no matter if there is one moon or if there are two... Hick!


The moon has become unreliable lately.  Recently it was decidedly hung over between 6 and 7 in the morning.  A shadow crept slowly over it, and the happy bright yellow light gave way to a sombre pinkish- grey.  It wobbled off amongst the trees, then disappeared over the horizon, looking very much the worse for wear.  I hope the moon recovers soon.


All a bit apocalyptic down here, what with the moon the colour of an elderly canned salmon and the South Island's biggest city being rocked by earthquakes.  Now we have a further portent of doom, at least to the profits of the airlines, in the form of volcanic ash in the atmosphere.  The ash is a little gift from Chile.  Both Qantas and Jetstar refuse to fly when New Zealand is under an ash cloud, but Air New Zealand seem to keep on grinding away at lower altitude.  Maybe it is a case of local knowledge that allows our national carrier to keep on flying when its overseas competitors are grounded, or is it that they have a fleet of rubber powered wind up aircraft that they wheel out when the ash is bad...? !  I am not sure if the bubble rising in my chest is one of pride, or fear...!  But, hey, if they are piloted by locals, they'll probably know where the farm airstrips are in case they have to put their Boeings down for a precautionary landing.



In addition to doing yet more glaze tests... on Thursday and on Saturday, I managed to make some bowls on the potter's wheel (Friday and Sunday I turned foot rings of the bowls that I had made the day before).  The bowls are mostly soup bowls or generous breakfast bowls, of the sort that might be nice to use on a cold winter's day when you want a good quantity of something hot to "stick to the ribs!"  I am talking "comfort food" here, and I kept that thought in mind as I made the bowls, making 30 of them deep, generous, curvy, and with a good turned over rim.   Whilst I did not slavishly throw them all the same, I did make them in "families", out of the same weight of clay, and to the same diameter.  I also did 8 bowls in a different style, much plainer and deeper, with no turn over to the rim.


It was nice working on the wheel, a reminder of why I do potting really.


I have been putting together some more glazes for testing, some glazes for the bowls, in particular two iron reds, and a tenmoku glaze, and I did some refinements and colour variations to glazes that I am probably going to use on the tiles.  Testing is a wearisome thing, and I do have to exercise quite a lot of will power to make myself work through a nine hour day of weighing, sieving, measuring, applying, and documenting a kiln load of tests.  I did a day like that yesterday, and was happy to walk out of my studio at 6.15pm and have a nice relaxing evening with my friend Peter W. in front of the television where we watched a video of World Cup Football (soccer), Spain vs Germany.  We do this one Monday evening every month, and are slowly working through last year's games.  I did sleep for some of the first half (as did some of the players ... apparently!!), but I managed to stay awake for the second half and for Spain's wonderful match deciding goal! 


Today I loaded up the kiln and prepared it to do a glaze firing.  I also stacked some of the half dry bowls on top of it to take advantage of the heat.  After I switch on the kiln I usually linger for a minute or two and check that each bank of elements is cycling on and off as it should.  Being a natural born pessimist, I don't take these things for granted!  Listening and watching the kiln is a useful habit to cultivate when driving an elderly kiln like mine, and I suspect it is a good habit even if you are firing one of those modern newfangled computer driven beasts.  On two previous occasions, my minute or two lingering beside the kiln at the beginning of the firing has saved me trouble later on, and today was another example of this.  I discovered that the middle bank of elements were on full, but were not switching off again as they should.  The middle simmerstat switch had gone bad.  Over the years the top and the bottom switch have been replaced, and I had wondered when the middle one's turn would come.  Fortunately I had a spare switch (I had bought two of them when I replaced the lower switch several months ago).


Pulling Things Apart..... Safely
Replacing the switches on an electric kiln is not something that you should attempt if you cannot understand wiring diagrams.  If those neat schematic lines, numbers, and wiggly bits, mean nothing at all to you no matter how hard you try to make sense of them, get qualified help! The thing is, if you make a mess of the wiring, and make the kiln unsafe, you could kill yourself, or someone that you love.  My father, an ex-physics teacher, replaced the first simmerstat switch on this kiln when that went wrong, and I was able to look over his shoulder and get some idea of what to do.  When it came time to replace the second switch by myself, I took the old one apart and compared it with the wiring diagram, so that I could be sure how it worked before I hooked up the new one.  This was because the new one looked very different than the ancient one that it was replacing.


The very first thing to do was to turn off the kiln.  First the switch on the kiln, then the switch on the wall, and finally the circuit breakers on the fuse box.


After I removed the metal cover on the side of the box on the kiln where all the electrical wizardry is gathered, I took a photo or two with the digital camera.  I do this whenever I am faced with a job like this before I touch anything.  It is so easy to forget which wire went where when you have disconnected a few of them, or if you drop something.


I placed the new switch beside the old one, and tried to figure out where the wires should go.  The new switch was quite different looking to the old one, which is probably 30 years old, so I was very careful to look at the wiring diagram and I looked at an old pulled apart switch that I had kept from the last time I had to do this job.  I examined the wiring to the other switches, and made sure I understood the logic of the connections before I undid anything. 


As I started to disconnect the old switch I also took advantage of the opportunity to look around at the condition of the other connections.  I discovered one connector where the insulation looked like it had got hot.  A careful waggle of the wire showed that the connector was slightly loose, enough for the joint to heat up.  I was able to tighten that connection, and replace another which looked worse.

When I was quite sure that I knew how to connect up the new switch, I made all the connections, and fixed the switch back in place.  I left the cover plate off the switch box so that I could observe things, from a distance, when the power was switched on again.


I reset the circuit breakers on the main fuse box, then put on rubber gloves before switching on the kiln.  Yes, really!  I am not an electrician, so I know that I can make mistakes, and rubber gloves could help prevent me getting electrocuted!  (The rubber soled shoes that I had on were also a good idea too!). Anyway all went well, the kiln hummed into life, nothing exploded, melted, or produced black oily smoke!  I switched off again, replaced the cover, and was able to continue the firing. Now the kiln is happily nearing the peak of the firing of the glaze tests and tiles as I write this.


I suspect that many potters have to fix things that they are not really qualified to do, simply out of economic necessity, it is hard to make ends meet as a potter, so I have written the no doubt "boring" account above in the hope that it might help you minimise some of the risks. 

Now I must away.... and check the kiln!

15 comments:

gz said...

you were lucky to see the lunar eclipse! Even without the clouds, I had a mountain in the way.

I'll be interested in those iron reds...

and yes, good to see the bowls

Peter said...

We were lucky with the eclipse, and we also saw one last December (I put a photo of it on my December 24 post). I was interested to see my photo of the earlier one shows the top left of the moon covered and the other two thirds bright.
I'm really hoping the iron reds turn out, I used to get good ones at cone 11 temperatures with a different recipe, and am hoping that the cone 9 ones will work OK. I'll post photos when I unpack the kiln. Just got to cone 9 10 minutes ago.

Linda Starr said...

Beautiful eclipse, can't wait to see the photos of the iron reds.

Angie said...

What fantastic shots ...love the colours ...maybe inspiration for a glaze colour ???? Well done on the electric front ...looks as though you have mastered another skill ...well done but take care.

cookingwithgas said...

Yes- we must tread where we have never been live taking on a new frontier.
I use to be the one to replace the kiln sitters in the electric kilns. The first time was a learning experience and then I got pretty quick with the job.
But I leave the mass of rewire to Mark.
Moon shoots are gorgeous and so are the bowls.
I love making bowls they are so rhythmic.
M

Judy Shreve said...

Peter - great shots of the lunar eclipse! That color would be a nice glaze!
Bowls are my favorite to throw and what I usually throw first if I haven't been at my wheel in a while - yours are wonderful - love the shape.
I'm lucky my husband knows all that electrical stuff - I would never attempt it!

Arkansas Patti said...

Thanks for the shots of the eclipse. It could not be seen here.
I am so impress how thorough you were replacing that switch. Well done.

Michèle Hastings said...

we lost a few pots while doing a bisque firing in the electric a few weeks back... bad top switch that turned on high without the switch even being turned on. thankfully we were near the kiln and were able to turn it off right away. like you, we always pay close attention to the kiln... it is also an oldie.
good that you had a spare switch!

Christine said...

Those are beautiful lunar eclipse photos, it makes up for missing it here, thank you. Reading through your account of replacing faulty switches, I was a bit worried when I came to the image of disembodied rubber gloves, it looked like you had evaporated! Good idea though. I too have had a few narrow escapes by lingering for a few minutes when switching on a kiln. I have a small top loader and a large front loader using the same control box. It is all too easy to fail to switch over the pyrometers. It happened once and hopefully never again. Boom!

Armelle said...

Very nice shots of lunar eclipse Peter, you were lucky to see it, here it was a rainy and cloudy night. The bowls look great, looking forward to see them glaze.
I would not be able to do such an electrical wizardy, and would have to call my friend !!!
A link to wonderful chineses chûn bowls : http://alaintruong.canalblog.com/archives/2010/09/17/19085651.html
Kind regards

Peter said...

Hi Everyone!
Thank you for your comments, for the encouragement about my bowls, and for making me laugh (Christine, the rubber gloves and my possible "evaporation"!). Interesting to hear others write about electric kilns too and the things that can go wrong! Glad that you enjoyed the moon shots, it was a strange thing seeing the moon go such a peculiar colour. It must be fun living on one of those planets that have several moons... Their sooth sayers would have have quite a time working out what all the strange combinations of shadows, line ups, partial and simultaneous eclipses meant!
Thanks Armelle for the link the Chinese Song Dynasty chûn bowls, they are quite beautiful, and it was very interesting to think about how to do similar decoration.... (at a sale price of $122,500 USD, it might be worth making a few!!!!).

Oh well, I'm off now to unload the kiln full of glaze tests and tile shrinkage tests..., Kind Thoughts to you all, P

Pat - Arkansas said...

Lovely eclipse photos, Peter. Thanks.

Who's a clever boy, then? Well done on your electrical replacement/repairs.

I had one of those "why didn't I think of that" moments when you wrote about taking a digital "before" photo. Many's the time I have scratched my head thinking how to put something back together. It's a wonder anything works after I've 'repaired' it. I don't mess about with electricity, leaving that for someone who knows more about what they are doing.

Peter said...

Hi Pat,
Not sure if I'm "clever", or just desperate! The good thing is that I did not barbecue myself or anyone else when I switched the power on again.

I find the digital before photo is really, really useful. Being of rather forgetful brain, I find it has been a great help with car repairs as well as dealing with the insides of the computer and the kiln.
:)

Lisa in that Auckland gallery.. said...

I'm still avidly following your work Peter - despite there not being any further sales here at Lopdell House Gallery. The bird jugs have prompted this message...WOW!! will we be seeing a Portage entry from you? I've been dying to ask and the time is getting closer for when the entries need to be in.... Perhaps a family of bird jugs? Imagine some crystal featherwork... I can hardly wait!!! This is Lisa, signing off. Ps - Nigella Stopit would taste absolutely terrible - take my word for it!!! ;-)

Peter said...

Hi Lisa,

Lovely to hear from you. Nigella Stopit somehow has escaped the cooking pot.... this time, and cabbages have been preferred in her place! I hadn't thought of bird jugs in connection to the Portage Awards, but it is a really interesting thought.... ! We shall see!

Best Wishes, P xx