Thursday, May 28, 2009

Loading the Kiln, Cleaning Shelves, and Chopping Wood!

To Celebrate the glorious news that I finally have loaded the kiln, I have put these photos back to front. So here is the loaded kiln! After this magical moment, the kiln door is bricked up, so this is the last glimpse of all the pots before they are unpacked.

It has been a really long job getting things ready this time. I split lots of wood on Tuesday, and hoped to have loaded the kiln Wednesday. On Wednesday I hit a snag. I found that the kiln shelves were likely to cause problems in the firing, due to an accumulation of flaking kiln wash* on the top and bottom surfaces. The kiln shelves are all second hand, and sadly, both top and bottom of the shelves were coated with something to protect them from the ravishes of dripping glazes and kiln atmosphere. When I got them, the coating seemed firm enough, but it has started to crumble after several firings. Trouble is, most of it is still really hard to remove, but some just falls off. I spent several hours on Wednesday removing what I could with a wire brush, and a brush attachment to the electric drill. A horrible job, and I spent the time with a mask on to keep the dust out of my lungs. I hope I at least removed what was loose, but would have liked to have got rid of all of the stuff that was underneath. I recoated the top surfaces with a 80/20 mix of alumina and china clay.

Dealing with the kiln shelves only left me time on the remainder of Wednesday to prepare props for the shelves. Checking the old ones, and making some new ones from cut down fire bricks. In the evening I taught a little class of teenagers that have started coming to me for lessons.

Thursday saw me actually loading the kiln, and whilst I was working a furry face appeared on top of the kiln. Evidently Ginger needs to supervise me, if I am to do anything right!

Here is the kiln partly loaded. There don't look to be many pots, but it is amazing what is actually hiding in there out of sight.

I made a discovery today when making up some extra thick kiln wash. The potter's wheel can be used as a large scale mixer. Just put the bucket of things to be mixed on the wheel, hold tight to your stirrer.

Then treadle away and the mixing is done really easily with leg power, rather than with the arms. Wonderful!

Wood, wood, and more wood. This is just a portion of what we have prepared for the firing. I was worried that we would not have enough really dry wood, as we have had lots of rain over the last few weeks, and some of the wood was getting damp from all that water and moist air drifting into the wood shed. I think we will be OK though. Today, Laura has been splitting even more wood, just in case. Laura also made a cake yesterday and dumplings for tea today, so deserves a medal!

(* Kiln wash is a protective coating that is often applied to kiln shelves and to the kiln interior. Just a protective layer on the top surface of a shelf is much better as it protects the shelf from puddles and drips of glaze, but avoids the risk of flaking bits of itself onto pots that are below it.)


Linda Starr said...

That's a whole lot of work scraping all those shelves, but speaking as one who has had a piece of kiln wash stuck in the middle of a really nice bowl, I think it may be worth it. I don't think I would attempt to stir on the potter's wheel, I would be afraid it would whirl around right off the wheel and all over everything. I use a paddle on an electric drill. Those are some big bowls/platters you have in there. The glazing for the top one looks very interesting. Good luck with your firing.

Pat - Arkansas said...

A fascinating process, Peter. Thanks for the details. Living in firing-ignorance as I do, I had no idea there was so much work involved. Whew!

I am intrigued by the large bowls and look forward to seeing photos of them post-firing.

Arkansas Patti said...

Aren't you clever with the foot powered mixer. There is always a better way to do stuff isn't there.
I love your overseer Ginger. Giving you the critical eye isn't he. He looks like he is feeling chipper after his mauling. Must be the good care you give him.
That is a pretty fierce pile of wood. I can only say, better you than me.
Can't wait to see the finished product.

Peter said...

Hi Linda, Pat and Patti, lovely to hear from you. Whew..., the kiln is all ready to go now with the door all bricked up and gaps sealed with clay.

I have been fortunate with the weather for the last 3 days as we actually had some winter sunshine. This was great as we could get firewood done, and the kiln loaded without everything getting wet. The sky is clouding over now, and we have a ominous looking weather warning as follows "HEAVY SNOW WARNING SOUTHLAND OTAGO : Bitterly cold southerlies expected to strengthen on Saturday night.In the 12 to 15 hours from midnight Saturday expect 5 to 10cm snow down to 200 metres but 15cm on the eastern ranges with lighter falls to sea level. Wind and showers easing after that, and freezing level rising slowly".

All going well I should get the firing finished by around 4 or 5 pm on Saturday afternoon before the worst of the weather if I get started around 3am, as my firings are usually about 13 hours, with an hour afterward to control the first part of the fall in temperature, and to seal up the kiln to stop the cold air rushing through the firebox.

I'm really hoping the big bowls turn out OK as I want them for an exhibition that I am taking part in in June (help, that's not far away!). Also have some teapots which I desperately need (one of them is for a commission). So, here's hoping.

I'll keep you posted. Depending on the result, you can either join me in cheers of joy, or give me therapy. Best Wishes, P.

Becky said...

Peter, wishing you the best for this firing. I suspect it will be extraordinary, given Ginger's presence as kiln god. Will look forward to pictures soon.

Becky said...

Tell the cowboys that according to the Language of Flowers, lavender signifies devotion. Their cowgirls would like that? It also signifies distrust. But you might want to keep that to yourself. ;)

Do you do mail order?

Linda Starr said...

I've got my fingers crossed for you Peter.

Peter said...

Hi Becky, thanks for your best wishes for the firing, I too am hoping that Ginger will rise to the challenge of making sure the firing is "extraordinary". I'll also have to make sure that he doesn't get too hot!

I had to chuckle about the cowboys and the Language of Flowers, so there is more to flowers than just their scent and good looks! I suspect you are referring to a comment I made on Linda Starr's blog, on her May 28 "U Pick" post (for those who haven't seen Linda's lovely blog and photo of her lavender, do take a look).

Regarding mail order, that is a very interesting topic. I notice that many potters in your part of the world use Etsy to sell their work, and I was wondering if it might work for me too?? If you, or anyone else that's reading this, have helpful advice or experiences with selling on Etsy, I would appreciate hearing from you. I have occasionally sold work by emailing a selection of photos and so on to people if they are interested, but Etsy does look a better way of doing things and probably makes the money side of it easier.

Hi Linda, thanks for that. I lit a small fire in the firebox to pre warm the kiln, I'm currently trying to decide if to begin the firing proper at 11pm tonight, or at 2 or 3 in the morning. I may try for a couple of hours sleep first.

Anton Sidko said...

Dear Peter, I can't find your contact details so I write here.
I'm a potter - hobbyist from Moscow. I hope to build the wood kiln for 1050-1150 C and use your blueprints for this aim. However I couldn't find data regarding fuel consumption to estimate price of firing so I ask your advice.

How much wood require your kilns for firing and which loading volume they have (volume of dry wood per kiln loading volume)?

How depends wood consumption on firing temperature?

Kind regards!

Peter said...

Hi Anton,
Good to hear from you, and I am delighted that you would like to build a wood fired kiln. What you ask regarding fuel consumption is almost impossible to answer, so much depends on the size of the kiln, how well insulated it is, the design of the firebox, and... probably most important, the person that is stoking the fire! It takes practice to learn how to fire a wood fired kiln economically, it is an art that I think is very similar to sailing a small boat. The theory is that big wood fired kilns fire more economically than little ones, but my best advice would be that you should build a small and simple wood fired kiln to begin with that is big enough to take 8 or 10 small pots, and have fun with it! Do several firings, and gain experience in controlling the rate that the temperature rises, and controlling the atmosphere in the kiln. See if you can make the kiln fire in oxidation, and in reduction when you want. Aiming for a temperature of 1050 - 1100 C should be
achievable by a small and simple kiln. (Higher stoneware temperatures are a greater challenge.)

One of the simplest wood fired kiln designs that would take you to at least raku temperatures of 800 - 900 C and probably to 1050C would be one like the kiln I made a plan for in my blog on 14 October 2009

This might be a bit too small for you, however a kiln like this one can be fast to build, lots of fun, and very instructive.

A slightly larger kiln that would hold a better number of pots, and should be capable of reaching at least 1100 C is one that I put on my blog on 13 July 2009

I built a kiln very like this that got to 1100 C with only a short chimney. The "improved" version of it that is my plan should go to 1200 C or so.

You don't need to build a kiln exactly to the plans I have on my blog, but use the plans to give you ideas. The bricks, kiln shelves, and other materials that you have available might determine the exact size that you build the kiln. You will need to experiment!

One of very small kilns I made would go to about 1000 C in a 5 hour firing and consume only 2.5 wheel barrow loads of wood. To be on the safe side, you should have at least a cubic metre of dry split wood available to fire a small kiln, and two cubic metres would be better!

Hope all that helps, do let us know how you get on!

Best Wishes,


Anton Sidko said...

Thanks for your advice! I hope it helps, anyway you give your the recommendation!)

If your are interested I could show you several pit fired works:

Kind regards!

Peter said...

Hi Anton,
Thanks for the links to your work. It is good to see what you are up to, thank you for sharing. I liked the "Kiln blooming" photo! Looking into a wood fired kiln when it is red hot, and glimpsing the pots inside it is one of the delights of firing with wood!

Do let me know when you build a wood fired kiln, it will be nice to keep in touch.

Best Wishes, P