Single firing

First of all, to clear up an issue from the previous post. I soaked my flaky kiln shelf and used a steel wire scrubber to remove the flaky batt wash and it worked like a dream! I thinned my batt wash with water to the consistency of skimmed milk and reapplied a thin layer and left it to dry. My kiln shelves look as good as new!

And now to single firing. I had used this technique when I made a birdbath as I was tight on time. The Mayco glazes are pretty steady with no movement at all. They also give a pretty good colour and coverage with just two thin coats. I glazed greenware and single fired the birdbath and it came out great. However I didn’t know how this technique would work with Amaco glazes.

I did a lot of throwing last weekend knowing that I wanted to use my Amaco glazes. However when I looked at my pyrometric bars, I saw I only had one or two bisque temp bars left! My little Olympic Kiln is old skool with a manual ramp dial and kiln sitter. So with precious bisque bars in short supply I thought about single firing my thrown mugs and bowls.

Amaco Potter’s Choice glazes mix and move and create beautiful effects but in order to do so, you need to apply 2, 3 even 4 coats depending on the thickness. I let my pieces dry to leather-hard and applied two coats of Toasted Sage then two coats of Indigo Float and two of Seaweed on alternate pieces. With all the glaze on they took a long time to dry but I was patient. I didn’t want to add too much because I didn’t want them running and ruining my lovely new clean kiln shelves.

I managed to pack the kiln with 3 layers and get everything in! And as I was doing a single firing I did a really slow low heat before raising the temp after an hour or two.

I fired to cone 5 and it took longer than expected to get to temperature, but it did get there in the end! I left the kiln to cool and opened up the lid holding my breath..

..Everything was in one piece! fantastic. But the glaze? ..it looked dull and thin. Not like Amaco at all and obviously not the effect I was hoping for!

20170805_145327

The only ones that looked decent were the two pots I used the tenmoku on first. I was hoping the Toasted Sage would be a little lighter than the grey but then again I hadn’t done a test tile and trying to guess colours from the Internet isn’t a good idea.

I admit I was a little disappointed but it’s all part of the learning process! I think overall I was happy that my single firing worked, it was just a lack of experience with Amaco glazes that meant I didn’t add enough layers.

I am confident that should I want to single fire again I could achieve results close to what I wanted.

I spent this morning re-glazing my mugs and bowls for a second firing! At least it won’t need such a long slow ramp as the mugs ceramic now but I still don’t want to rush and risk an exploding kiln! I added more layers of each glaze but also more stripes of Indigo Float and Seaweed. The colours look great when they interact so hopefully this will achieve that effect.

20170805_145347 Once they’re dry I will fire them again, sometime early this week if not tomorrow and post the final results!

I guess I’m must also admit that I’m keen to get single firing experience as it saves a lot on the electricity bill!! And if it produces the effect you want, then why not single fire? My only advice is to make sure your pieces are dry as a bone before firing and then allowing a long slow ramp. I was advised to leave extra clay clean from glaze to allow gas to escape from ghee clay body, but I just left the bottoms clean as usual and this was fine.

Happy potting!

PS xx

Advertisements

Birdbath

A dear colleague at work is leaving and I wanted to say thank you in a meaningful way. So. What better than making him something! I know he loves his garden and so a flower pot or birdbath came to mind. Having made a few oblong slab built flowers pots recently, I thought a birdbath might be fun to make. 

I began with a former shape. I used a straw to poke through three holes, however I wasn’t sure what detail or design to do. I wanted I didn’t know if a country garden, traditional birdbath might be most appropriate or something a little more fun. I thought perhaps a little bird on the side but it didn’t seem very original. Something work related would be fun, perhaps? So I created a little tube train coming out of a tunnel along one side!

In my haste to glaze and fire it before he left, I read that you can use Mayco glaze on leather hard clay, meaning a single firing!

…well. Needless to say, I thought the piece was dry and after opening the kiln, my heart sank. It had cracked and broken into pieces. 

Not to be put off, I got straight back to my bag of clay and this time I rolled a slab and used a large mixing bowl to form the base. I cut a separate piece for the rim and once these were suitably dry I made the holes and stuck them together. I let the pieces dry a little more before using  my Mayco glazes and designer liners. I let the pieces dry over the weekend while we were off visiting Middleport Pottery (blog post to follow!) and I fired the pieces Sunday afternoon. 

I was so happy and relieved!! The colours came out well and most importantly it was all in one piece! I ran to a hardware store and rather than paying for expensive chain I found three sink-plug chains. These chains were perfect, 45cm long, rust resistant and they even had the little opening loops at each end!

I gave my colleague the birdbath this week and he was absolutely chuffed. It feels so good to show someone your thanks and gratitude with something you’ve invested time and effort in. I’m going to miss him at work but at least he has a little birdbath to remember us all by!

Birdbath making was fun and the actual shape is no more complicated than a dish. I’m looking forward to making the next one! I’m also really happy I can now single fire my pieces using the Mayco glaze – saves time and electricity!!!

Look out for some birdbaths on my etsy page coming soon!

PSxx

First Bisque Firing… Uh Oh.

 

Last night I tried my first biscuit firing. I had made a few small egg cups, a mug and some tester discs for my glazes. Everything seemed ok and I was set for a 7 hour firing, including an extra hour on the dial. I was home and started the kiln low then ramped up slowly every hour at first then two hours. However when I went to check on the kiln at the 5th hour, the light was off and I couldn’t hear anything. It was still hot but I didn’t think it was working. I left it another hour and when I cam back the handle was cool enough to touch. Something had gone wrong!

I tried to turn the kiln on and off but nothing was responding. I checked the cone and it hadn’t bent at all, so it hadn’t gotten anywhere near 1000 oC. I’m guessing it’s something electrical.

It’s frustrating. I’m away this weekend and I’m not sure what to do. I could open it up, but I’m not sure what I’m looking for. SB said she has a good kiln guy, perhaps I’ll call him and see if he can diagnose whats wrong.

If anyone has any tips or knows of online resources to help diagnose kiln problems please let me know! The stumbling block I’ve come across is that it is an old kiln and most things online are far more modern. Mine doesn’t even have a programmer!

Frustrating! But the price you pay for a cheap second hand kiln I guess.

PG x