Thursday, January 13, 2011

Crystals in the smoke!

Close up of crystals with carbon trapping.

A little bottle 5.5 inches high (140mm)

Bottle smoked and heavily reduced with copper metal formed on glaze surface.

Vase with carbon trapped crystals. 6 inches high (152mm)

Bottle with light reduction atmosphere. 9.5 inches (240mm)

Vase with heavy reduction and carbon trapping 10 1/8 inches high (256mm)

Copper green vase fired in electric kiln only 9.5 inches high (240mm)

Bottle 6 1/8 inches high (155mm). Two glaze firings in electric kiln.

Bottle 6 7/8 inches high (175mm). Two glaze firings in electric kiln.


Mug with blue crystals on pale green background.

I made an almost matching pair!

I have fired my little wood fired kiln 4 times now, three times since I last posted, and I have done a couple of glaze firings in the electric kiln as well. It has been a busy couple of weeks.

I love the little wood fired kiln. It is nice having something that I can fire rapidly and economically, it is possible to learn so much that way. The last firing that I did only took about one and a half wheel barrow loads of wood to fire. Last weekend I fired on Saturday, and then fired again on Sunday. I can fire fast or slowly with the kiln, and can fire quite accurately.

It is very interesting using a wood fired kiln to modify crystalline glazes that have first been fired in the electric kiln.

Getting just the right atmosphere in the kiln to achieve the colour change in the glazes that I am after is a challenge. My first three attempts produced too much carbon, and my next attempt had just a little too much oxygen in the atmosphere. I am making progress though, and feel that I am much closer to understanding the process and getting things right. Some interesting pots have come out of these initial attempts, and the excess carbon has sometimes produced pots with lovely black crystals on pink or gray backgrounds.

In addition to the experiments with the wood fired kiln, I have also continued further with refining what I do in the electric kiln. Some pots, in particular ones that have had two glaze firings, are turning out really well, and are giving me more ideas about my firing schedules. I am doing another electric firing as I write this tonight and the firing will continue through much of tomorrow.

It has been two weeks of hard work, but I have got some ideas flowing along, and it is fun to be firing a wood fired kiln again. One really interesting development from this might be to make some "useful" raku pots. I have been getting some raku-like effects in these firings, and have done it with pots that have been fired to vitrification. The pots would be robust, water proof, and useful. I actually fired 3 small raku glazed test pieces in one of the firings, and reduced the glaze to shiny copper metal...

Anyway, must dash and check the kiln. I'm hoping to get it to a suitable temperature by bed time where I can get 4 hours sleep before having to check it again.

Happy New Year!


Linda Starr said...

Haven't heard from you in a while now I see why, beautiful crystals again, great work Peter.

ang said...

wow they're certainly coming along love no.7 very ancient looking...anyhoo i tried the firing of my beige shinos in the bisque firing and some did pick up a little colour, will try another batch in the next bisque too, i have read that it could also be the slow cooling cycle of the bisque adding to the colour as well as combustables.. nice one peter your handy hints are welcome anytime :))

Pat - Arkansas said...

Oh, my goodness, Peter! Those pots are gorgeous! You've been a busy bee, with wonderful results!

Dad said...

Lovely results Peter.
I don't know what Miss Unsworth would say as the potential is being real-ised!
Take care though; sleep deprivation ruins concentration (as you well know!) ... and shortens life spans. We don't want to lose you just yet!

cindy shake said...

WOW! Those are really cool! They have such a organic quality to them -some look like geodes(sp?) And those MUGS!! Beautiful. Happy New Year!

rwhendrix said...

Your crystal pots are always fun to look at. Id like to see a picture of your little wood fired kiln.

Kitty Shepherd said...

I think those mugs are quite magical! Great effects all round, you must be delighted.

Peter said...

Dear All.... Agggggggggh! I just posted a long comment to you all and Google gobbled it up! Never mind, these things happen! I'll try answering you two at a time and see if Google will play fair!

Hi Linda,
Lovely to hear from you. Sorry that I have been working away in silence at this end of the world. I was trying to meet a deadline for some of the work, and just kept running out of hours in the day.

Hi Ang,
Glad that you got some colour back in the shinos with the second firing with a bisque. It is a useful trick to pull out when things don't quite work the first time around. I think the real reason that it works is to do with the iron that has been pulled through into the glaze from the body of the pot when it was fired in reduction, is given a chance to change from its grey oxygen starved state, back to oxidized red iron oxide. This gives a healthy glow to the shino. It does also make me think that shinos probably should benefit from a "cleaning up" oxidized period in their glaze firing, just before shutting off the fire and clamming up the kiln.

Peter said...

Ha.... I got the first two replies through!

Hello Pat,
Good to hear from you. I certainly have been buzzzing here! It is nice to have made some progress with new work, and to have some new challenges too.

Hello Dad,
Mmmmmmmm sleep would be a very welcome commodity in this household. I guess that I can be very thankful that the life I do have is not boring. I am convinced that a long and boring life would be far worse than a short and interesting one... for some reason Mozart springs to mind! Anyway, I will try and remedy the sleep side as much as I can. At least the latest deadline has been met.

Hi Cindy,
Lovely to hear from you all the way from the frozen north! Happy New Year to you too! The carbon trapped crystals make me think of fossils, and sometimes of various print making processes.

Peter said...

Yay.... Google must like me again!
Hi Richard,
Nice to hear from you. I will probably do a rebuild of the kiln in the next few days as I would like to make it slightly larger and a bit more permanent. When I work on it I will be able to take some photos and do a scale drawing. I put the kiln together in such a hurry that I omitted to do such things when I was building it! I also would like to do a test firing just to get more idea of how high the kiln will fire. So far all firings have been only the 800 Centigrade needed for the process I was doing. I think that 1100 C will be easy to get, but above 1200 C I am not sure.

Hi Kitty,
Greetings to you in sunny (I hope) Spain! I am pleased with the progress with the mugs. Still want to press on with more variations. I want to try some experiments with using a colour instead of the white area that is above the crystal glaze on the outside. It may well run into the crystal part though, so.... we will have to see how that goes!

Angie said...

Love the effects you are achieving.... and I am so in love with that pair of mugs.

Peter said...

Hello Angie,
Good to hear from you. I wish you lived a bit closer, then we could give you a cup of tea out of one of my mugs!