Thursday 28 March 2013

Life and death.

Easter hasn't ever really meant much to me. I'm not religous and only ever think of it as a holiday half way between Christmas and summer. However, sometimes things happen that focus one's thoughts a little more than usual.
I've been teaching the Easter story to my class at school this past few weeks. Going through this ancient story with my class has led me to look at it again with fresh eyes. I've found that this happens a lot when teaching something that you've known for years. You have to unpick the details, so that you can give a clear explanation. Teaching a subject always gives me a much deeper understanding of it than I had before. So, the story got me thinking about this deeper understanding I'd acquired and, of course, about new beginnings.
Then,this afternoon,  just as I was trying to make sense of all these thoughts, I had some very sad news about a death in my family. While I was driving home tonight I got thinking about this special person's legacy. She'd made a difference in the world. She'd raised a beautiful family who've all gone on to make a difference in their own way, as, in turn, will their children. It's sad, but beautiful.
Finally, I arrived home and was greeted with some new arrivals in our house (below).

As I said, I'm not religous, but the events of this past few days have certainly made me think about life, death and the future. Days like these, that supercede the mundane, make me feel as though I've reached a turning point.

It's not a post about pottery (I don't think?), just musings about my day.

Photo: Our new girls!
They don't have names yet, any suggestions?

Friday 22 March 2013

Today and last year in film!

A quick clip made by my daughter on the ipad - sorry it's poor quality, I don't know much about file formats etc. It's something I'd like to get better at! This second video I made last summer - I just wanted to feel warm again!

Wednesday 20 March 2013

New Firing schedule

I was really eager to see the results of this glaze firing as I'd tried a different firing schedule. In previous firings I'd basically brought the kiln up to cone 9 temperature, reduced for half an hour and then oxidation until cone 10 falls. After reading more about gas firing schedules I decided that I needed to have a much more controlled approach to firing if I'm ever to produced consistently repeatable results. I used two packs of cones in this firing; a set for the reduction stage (cones o11-o9) and a pack for the final temperature (cones 8-10). I steadily brought the temperature up to cone o10 and then put it into reduction for half an hour. I closed the dampers and partially blocked the flu with some firebrick. During the reduction I increased the gas pressure slightly. I was a little surprised to see the temperature continue to increase during the reduction, as it usually really slows at this point. Following the reduction I opened the dampers slightly  (1/4 inch) and opened the flu to try and create a neutral atmosphere. the plan was to maintain these settings until cone 9 fell and then open all dampers for a final period of oxidization until cone 10 fell. However, the kiln stalled at just below 1200 degrees c. Cone 9 had fallen and the kiln was in full oxidation, but never reached cone 10.
In retrospect I realise that I had the bottom shelf too low. It was packed with lots of flat heart wedding favors and a couple of canister lids, with the shelf above only an inch or so higher. The lids were a dull grey blue and had clearly not had a good reduction as they were meant to be a bright blue. I think the low shelf had affected the convection within the kiln, resulting in the failure to reach temperature.

Overall, the firing results were mixed. The tenmoku glaze fired well both in the top and bottom of the kiln. The reduction at the bottom meant that the canister lids were a different colour to the bodies which renders them as seconds. the wedding favours which were decorated with copper oxide fired well despite not producing the colours I'd hoped for. the glaze on a couple of the mugs ran onto the shelf and then split when they cooled. here a re a few photos.

 
I was quite pleased with the fruit bowl.

 
I made 50 of these favors, most of which were on the bottom shelf of the kiln. the writing had copper oxide rubbed into it. A combination of their position in the kiln, the lower temperature / poor convection led to the resulting colour I think.
 
 
The Tenmoku glaze fired really well throughout the kiln.
 
 
I stupidly placed the lids of these canisters in a different part of the kiln to the bodies, hence the colour difference.

 

Tuesday 12 March 2013

Exploding pots...aaagh!

Pride comes before a fall! I was so proud of my first bread crock and had been thinking about how I was going to decorate it. In my eagerness to get it fired it seems I didn't get it thoroughly dry before the bisque firing. I brought some of the pots into the house to try and dry them out quicker. I usually leave them in the oven for an hour or so before firing if I'm in any doubt about their dryness. In this instance i thought the pot was dry enough.
The broken lid is only part of the damage. What you can't see from the picture is the big hole in the pot's base. :-(


On a brighter note, I've joined UK Handmade today. Early days yet, but you can see more at: http://ukhandmade.ning.com/profile/DavidBarber

Saturday 9 March 2013

Saturday 8th March

Throwing soup bowls today. Really enjoyed making these. Izzy came in to take some pictures, she's snapping everything at the moment in the hope that she'll find a winning picture for the rotary club photo competition. She also added her own creative touch...see below!







Wednesday 6 March 2013

Reclaiming clay

To reclaim clay you'll need two of the most valuable commodities a potter has (or hasn't in my case) - time and space!
It's not the most glamourous part of the pottery process, but unless you want to disappear under an ever increasing mountain of clay scraps and slurry, reclaiming clay is a necessary evil. This weekend I plan on preparing to reclaim. I don't have a pugmill (yet), so have to reclaim manually. To do this I have to make sure the clay is fully dried out. During winter this is not as easy as it might seem. Up until recently I've been drying my pottery in the house as the studio is always too cold. However, I've now installed a wood burning stove in there and so hopefully this'll speed up the drying process.

Once I've got a bucket of dry clay I can then smash it up with a hammer into smallish (gravel sized) pieces. I'll then pour the dry contents into a bucket with an old cloth lining it. (The cloth helps when lifting the wet clay from the bucket. I have seen a wire wastepaper basket used as a bucket liner to lift the clay out.).

Next I fill the bucket with water and a drop of vinegar. The vinegar helps to break down the clay quicker. After a few days I'll drain off some of the excess water leaving behind clay that's a thick buttery consistency. This mixture is then spread evenly over a plaster bat. (I make my plaster bats by pouring plaster mix into large thick foil turkey trays).

As the clay drys out I'll turn it so that it drys evenly. once it becomes stiff enough I'll knead it and then store it in plastic bags.

i'm hoping to get a pugmill this year to speed up this process, but of course this involves those other commodities that are alsways in short supply, - space and money!

Monday 4 March 2013

Throwing large

I've been throwing larger pots recently and have had to put in some concentration as well as sweat. As I don't throw larger pots very often, I have to re-learn how to do it. This got me thinking that I should write down the little lessons that I learn and save myself some time in the future. Hence this post. These are based on my experience of throwing 10lb and upwards lumps of clay.

1. Make sure the clay is well kneaded and not too hard. This really helps when it comes to getting it centred. Well kneaded clay responds much better when on the wheel.

2. Centering - this is something that really takes a bit of muscle (see point 1 - clay that's not too hard). I try not to rush centering larger lumps of clay, you have to be patient. Keep the pressure on the clay using equal pressure with both hands - left hand from the side right hand from the top. Use the full spread of your hands. With larger lumps of clay I use my forearm as well! Be beligerent! You're the one in charge and the clay will eventually respond. The main thing is don't rush.

3. Opening - again you can't rush. Concentrate on forming the base of the pot. I tend to pull the clay out wider than I want the eventual base as when I begin to pull the walls up the base naturally gets narrower.

4. Pulling the walls - As with all pots, get the height first (don't rush). I've tried several ways of getting the walls to come up consistently from bottom to top. There are several techniques that you can use -fingers,  knuckle lift, palm lift etc. I've tried all of these, but tend to encounter problems with the clay getting 'dry' during the pull causing an uneven pull. Personally with large pots I prefer to use a sponge in the right hand to ensure that the walls remain lubricated during the lift. As you make more pulls take care that the walls at the top don't get too thin - remember, you've still got to leave some clay to create the width! make sure that you're bringing clay up from the bottom, but be careful that you're not digging in too much at the bottom with your right hand. If the walls at the bottom become too thin they won't hold the weight of all of the clay above. Conversly, if the walls at the top become too thin then they'll fold. Leave plenty of clay at the top to make your gallery (if you're including one).

5. Add the gallery before shaping the pot. If you try to do this when you've made the finished shape then chances are the downward force that you'll need to apply when forming the gallery will cause the walls to buckle.

6. Form the shape of the pot carefully and always keep in mind that the clay at the bottom of your pot is carrying a lot of weight - pull it too thin and it'll slump. If it does start to lose its shape and you try to get it back into shape you'll more than likely cause the top to lose shape and at worse slump.

7. Know when to finish. Something i never seem to learn!

I'm sure that there are far better guides to making large pots, these are what seem to work for me.
I'll try to make a video and put it onto my youtube channel next weekend.

Saturday 2 March 2013

Big pots.

I've been quite busy recently, getting pots made. I made a few tea / coffee cadies and posted some pics on my facebook page. This led to someone asking if I could make a bread crock for them. I don't tend to throw large pots very often as they take up so much space in the kiln. However, as I have a couple of tall pots sitting on shelves in the studio waiting to be fired I thought that one more large pot could make a kiln full of these bigger pots. The bread crock was made from around 9lbs of quite stiff clay. It was a real wrestling match getting this centred and I probably could have saved myself a workout by using softer clay; lesson for next time!
I've just finished lugging the bread crock and I'm pondering what if any decoration it'll have when fired. I also threw a handful of soup bowls tonight with a flat rim that'll be great for adding decoration to.
I'm really enjoying making pottery now that I've fitted a stove in the studio. it's so much easier to find the motivation to go into the studio when it's warm in there!

I included the mug in the picture to give some indication of the size. The picture on the left was pre lugging. Sorry about the poor quality of the second picture.