Category Archives: Soda-firing

a (follow-up) study of clay bodies from Continental Clay fired in a soda firing

Collage of Continental Clay clay bodies soda fired to cone 10 in reduction.

Over the years, you may have come across some tea bowls that I made of the clay bodies at Continental Clay in their shop in Minneapolis and also shared in a previous blog post as well as. The blog post still gets a ton of visits, but it felt like time to update them… it has been 13 years! New examples! Better photos! More clay bodies!

I use these examples to help my students at the Northern Clay Center choose what they want clay body they to use (minus soda and woodfire clays). I hope these photos capture the range of finishes these clay bodies give and can help some of you decide what you want to use, too! Each piece is glazed in a thin shino, just on the interior. The soda ash in the shino comes through the wall of the bisqued clay and adds another level of flashing to the piece! All pieces were fired to cone 10 in reduction with soda sprayed in around cone 9. I’ve added some thoughts on each of the clays. I highly encourage you to play around with different clay bodies in soda – whether it is from Continental or another supplier. You can change the surface of your piece with flashing slips – or by switching up the clay!


First up is the Soda Clay body from Continental Clay. It has beautiful flashing and great orange peel that can have a lovely green color to it. It is groggy and can be rough at first, but you’ll quickly get used to it quickly4. But it will dull your trimming tools quickly! It has some excellent durability that can stand a lot of abuse. It seems like it has an above average high alumina content and can be a bit dry when not hit with soda. But a lovely range of flashing and texture to it. When I was primarily soda firing, this was my main clay. It a custom body that we used at Lillstreet, and then CC adapted it into their own Soda Clay body.


The B Clay from Continental Clay is a dream to throw and can flash spectacularly in a soda firing. Especially with shino as the liner glaze! The range of color is wide. And although this sample is very colorful, it still doesn’t catch all it can do. If it is in an oxidized pocket of the kiln, it can be more tan and even in color. It’s the top clay body choice by my soda students at NCC. And probably my favorite clay to throw. Both B Clay and porcelain do some extra flashing when lined with shino.


Grolleg Porcelain has my heart! It can be fickle, but when it does its thing, it is glorious! Again, the secret is glazing with shino as a liner so it takes the flashing up a few notches. Check out the range of colors! The peachy color really comes out when the piece is thin and a liner glaze of shino is used. If Grolleg is in a pocket of oxidation, it can be just white. Or if it is in a heavy soda and reduction area, it can be a shiny grey sharkskin finish! This is the main clay I use in my cone 10 oxidation work too.


The test cups that I’ve made of Domestic Porcelain from Continental Clay in the soda kiln always crack me up. I made one, fired it and it came out miles more gorgeous than any other example that I had seen of the clay come out of the soda kiln. So I made ANOTHER one and fired that. And that was equally stunning. But seriously, it doesn’t usually look this dynamic. It’s a nice clay body – and is significantly less expensive than Grolleg, but out of the soda kiln, it usually gets an “eh” from students who try it. But I can’t seem to recreate the typical results it on my test cups. Maybe the kiln is just messing with me. Or maybe it just reacts really well with shino on the inside and thin walls. So I will leave it all up to you to decide if you want to dive in with Domestic Porcelain or not. And maybe share some photos so I can see what’s happening in other kilns!


Wood Fire Porcelain is one of the Continental Clay clay bodies that I haven’t worked much with, so my opinions and information is limited. I had been expecting more range of color, but on the pieces I have soda fired, the color range is limited to mostly tan with hints of peach. It throws nicely (especially for a porcelain!). And feels like you can push it quite a bit. It can go up to cone 12. I really loved throwing it. And have fired a few pieces in c.10 oxidation too. It’s a bit creamier in color than Grolleg, but it is a small difference. I’m excited to fire this in a wood kiln sometime! The pieces I have seen that have been woodfired are gorgeous.


The Fireclay Stoneware from Continental Clay is a toasty choice for the soda kiln. It throws well and has a nice range of warm tones in it. It doesn’t attract soda as strongly as the B Clay. So there can be dry spots if it doesn’t get a direct hit with soda. But when it does get a heavy hit, there can be some rich dark tones that are quite stunning. I enjoy the Fireclay Stoneware with flashing slips brushed on. The contrast can be quite stunning!


The Fireclay Stoneware with Iron from Continental Clay is the same body as above – but with some extra iron oxide added. That iron gives it an deeper, darker color in soda. I have had some students who are looking for a metallic finish and they will use this body, and then use an iron oxide wash on top of it. I love applying a light colored flashing slip with a coarse brush. And glazes that really react to iron really shine on this clay body.


Buff Stoneware is another clay that I haven’t used that much. But my students do use it regularly. It is a sandy (as opposed to groggy) clay that always feels kind of “fluffy” when I throw it. And when that thought pops into my head, I always chuckle to myself. How can clay be fluffy?! The orange peel texture from when it is hit with a lot of soda is much finer than the Soda Clay, for example. It’s a nice body to throw and has nice toasty flashing in the soda kiln.


If you’re looking to work in a thick, sculptural way, there is nothing better than the Raku Clay body from Continental Clay. It flashes a warm, toasty color in soda. It resists soda so it rarely gets too juicy, in my experience. But its unique coloring and durability is sometimes the best choice for some pieces. It can take a lot of altering, paddling and variety of thicknesses. I also enjoy the clay that is revealed from the rough, quick trimming. I haven’t used it much, personally, but I’ve had quite a few soda students use it so I’ve seen many examples over the years.


I thought I’d share some of my favorite clay, in action. This pair of mugs were made from Grolleg Porcelain. The darker band is smooth orange flashing slip. And the blue is spray of Randy’s Green. They are lined with shino. And the reds/ pinks are copper that is flashing from the copper rich glaze that is sprayed on. I had to keep this pair in my own collection. All the parts came together so beautifully that I knew I had to keep them around because there was more to learn from them.

https://www.instagram.com/p/BUSVN_thFDn/

Testing (mostly) Amaco underglazes in a soda kiln

A sampling of Amaco underglazes in a soda firing.
A sampling of Amaco underglazes in a soda firing.

I love data! In all of my years of teaching soda firing at Lillstreet Art Center and at Northern Clay Center, I always have students asking questions about what underglazes might work in the soda kiln. There is often a desire to get a touch of color that is best achieved with an underglaze. But hard to know where to start! And some of them can be pricey (hello reds!). So I did some crowdsourcing with my NCC classes to test the Amaco underglazes that we collectively owned. Most are the line of Amaco Velvet underglazes (that’s what the V is for). But there are a few other lines (DV and SS) that are discontinued. But jars are still floating around out there so we tested the ones we had. Some of the Designer Velvet underglazes are gorgeous! Firing underglazes in reduction, at cone 10 is not a typical use. So you can’t get the information you might be looking for out of the maker’s test tiles. These test tiles have been invaluable to my students. And I am hoping that this post, sharing them, will help many more!

a guide to Emily Murphy's underglaze test tiles in the soda kiln.
I made this little guide to the test tiles that I made so you can see how each third of the tiles were created. Isn’t it cute? I tried to fit as much information on each tile as possible. Although you know with soda firings, the range of possibilities is huge. These tiles are more of a guide to tell you what might be possible.
Please note: the Smooth Orange Flashing Slip recipe is included after the test tiles!

blacks and grays


whites


reds


pinks


oranges


yellows


greens


blues


purples


browns


Recipe for Smooth Orange Flashing Slip for the soda kiln
Here is the recipe for Smooth Orange Slip used on the test tiles under the striped area. There is some wiggle room on what clay bodies you use this on, if it is applied to bisque or leather hard clay. But generally, it is best on leather hard clay. And must be fired in an atmospheric kiln to flash. Otherwise it will just be white!

Oval vase by: Emily Murphy (me!)
photograph by: Guy Nichols

I am happy to be back to blogging! Thanks for reading and sharing!

From my last soda firing

I put this most together last week but didn’t manage to post it before heading north for the weekend.

As I mentioned in my last post, I fired my first soda kiln of 2009 last Sunday.  I unloaded it on Wednesday between classes and managed to snap a couple of quick pictures in the process.  We’ve been having some crazy weather here in Chicago that has kept me from going back to my studio to spend some time with these pieces and to take more pictures. We’ve had back to back to back snow storms and it got cold enough for the thermometer to hit -15°F. That meant that I didn’t get back to the studio to take some decent pictures before heading out for a road trip, but I thought I’d share a quick sneak peak from the unloading.

I’m hoping that I can figure out a way to capture the surface of this piece.  It is full of little sparkly crystals. I’ve never had crystals develop over such a large area in this kiln before. Of course you can’t see them in this picture, but you can see the kiln wash splattered floor in the background!

platter

This is one of the espresso cups and saucers that I mentioned before.  This sweet little cup is maybe just under 3″ tall.  While I was unloading, I discovered that one of these saucers mysteriously made it into the kiln without any wadding… oops!

espresso-cup-saucer

I’m regretting that I didn’t take a pictures that had any sense of scale.  This teacup is much larger than the espresso cup above.

teacup-saucerThis firing was all part of a large dinnerware set from a wedding registry that I have been working on for my friends Beth and Lars.  Hopefully I’ll get some better photos of the set to share here soon.

Dinnerware, a platter, wall vases and a whole bunch of cups

As promised, here are some photos of some recent work. I got them out of the kiln right before our July road trip. And had the photographed this week by my photographer, Guy Nicol.

This is some new dinnerware that I’ve been designing:

And this is part of my newest platter series:

I’m really excited for these new wall vases.
These pieces are sort of a hybrid between my oval vases and the wall pieces.
And this is a new surface that you’re going to start seeing on more of my pieces.
I’m really excited for a floral designer to go to town with them! Unfortunately, my favorite designer, Amy Lemaire, has moved away! Amy has done all the arrangements over the past 4 years. You can see some of her past work here

I think I’ve mentioned before that I’ve been in a cup making groove.
I really love the curve & tension in these handles.


You might remember these masked mugs from an earlier post.
The curve of this mug makes me want to fill it with hot cocoa and cup it in my hands on a cold autumn night. That’s not going to happen for a while.
And here are the peace cups that you might remember from a previous post too.
hope. peace. change.

Resources for Soda Firing

I thought that it would be fun to try to round up as many online resources for folks who are interested in soda firing and put it together into one handy post. Since there isn’t that much publish (relatively speaking), I think it has the possibility of being relatively comprehensive. I hope you enjoy reading the results of my research as much as I did!

Online Soda Groups:

Salt/Soda Firing Discussion Group

You might remember this site that is all about Salt and Soda firing that I wrote about a while back. It’s a social networking site for all people interested in these firing processes. There are some fantastic potters and sculptors that are a part of this site as well as students who are just beginning to dabbling in soda. I highly encourage you to dive in- sign up and make a page. The more the merrier (don’t be shy if you’re just beginning in soda!) There are recipes for slips and glazes as well as a forum for putting questions out there. Are you thinking about converting an old electric kiln into a soda kiln? There’s a discussion going on here for you. And this site is always evolving- it’ll be whatever the members make it.

Salt & Soda tags on the ClayArt archives on Potters.org. It’s worth digging into. It’s quite possible that someone else had the same exact question as you 8 months ago.

Blogs that focus on soda firing:
(I had to draw a line somewhere… so I drew it at soda firing bloggers. If I’m missing any, please let me know!)

Of course there is this blog, PotteryBlog.com. About 95% of my pots are soda fired, and I try to share with you interesting soda information. Soon I’ll be posting a whole bunch of information about the use of whiting in my soda mix (the soda geeks will be psyched for this one!)
Here are some posts that you might find extra interesting if you’re a soda firing fool:
What is Soda Firing
A Happy Soda Firing
Hot Pots 

Julie Rozman, a fellow Lillstreeter, also writes a blog, Design Realized. She shares a lot of her glaze testing and firing info on her site. You should be sure to check it out!

Scott Cooper makes beautiful wood & soda fired pots. He also writes about his work and process in his journal, This Week @ St. Earth. You should also be sure to check out his “process” page where he has tons of information that is interesting and helpful.

 

Keith Kreeger makes salt/soda fired pots at his studio/gallery on Cape Code (although he has been venturing into earthenware lately). You can learn more about his soda work on his blog, Kreeger Pottery Blog.

I just discovered Joy Tanner’s Blog. I’ve gotten to know Joy’s work through the Salt/Soda group and I’ve excited that there is another soda firer writing a blog!

Websites that have a wealth of soda info on them:
(These are sites that have information on them about soda firing- kiln info, recipes, etc…)

  • Julia Galloway’s Alchemy page. Julia generously shares with her information on cone 6 soda firing, including slip and glaze recipes.
  • Scott Cooper (as mentioned above) has a great process page with tons of information on kiln building, glaze recipes and even clay recipes. Not to mention some beautiful pots!
  • Robbie Lobell makes beautiful, elegant soda fired ovenware and tableware. He has a page on his site about his kiln and soda firing process. He lives in Coupeville, WA mentions on his site that he will rent out 1/4, 1/2 or the whole kiln to experienced firers.

Books on Soda Firing:

Soda, Clay and Fire by Gail Nichols is a must have for anyone interested in firing with soda. This book is the culmination of Gail’s PhD work in soda firing in Material Science at Monash University in Gippland, Victoria, Austrailia. The research is incredible and it’s an easy read. Two things that don’t always go together so easily. I think if you picked up this book knowing clay, but not knowing soda, you might decide that you need to start soda firing by the end. But I’m a bit biased on these things. You can also learn a bit more about this book here.

Ruthanne Tudball’s book, Soda Glazing is the original text on soda firing. There has been so little actually published on soda (especially in comparison to other firing techniques) because of the youthfulness of the process. This is a book that I kept close to me for many years. There are overviews of different potters and their soda approaches as well as a great index of glaze, slip and clay recipes. Again, this is a book that you need to have on your bookshelf if you’re making soda fired work.

Online articles about soda firing:

Videos about soda firing:
(if you’re reading this through your email or a blog reader, you’ll won’t see the videos below. Just head over to Pottery Blog to see the videos)

From Pottery Northwest:


And a series of 3 informative videos from
Jeffrey Huebner:



I really have enjoyed this. Please send me links to things that you think might be missing from here and I’ll keep updating this post. This was a big project and I had to put some sort of limits on it. I decided not to include links to soda firing potters & sculptors in this post. I know that there a ton out there with great websites, but I thought I’d limit it to sites that had technical information on it. Another post will be soda firing ceramicists. That will be fun ; ) If you want to give me a hand with that, just leave a comment with suggestions for me to include. Just remember: folks who fire with*soda* or *soda/salt,* but not just salt.

Hot Pots

I fired a kiln full of pots last week in the soda kiln. It was chock full of cups, but that’s the subject of another blog post. It was a pretty fun load. There were a couple of new clay bodies, new glazes and slips. Lots of testing and playing around led to many late late nights at the studio in preparation for this kiln. I ended up with was about a kiln and a half full of work, so there will be another one soon!

The image below is of the wall of the soda kiln. Isn’t it beautiful? The walls are actually glazed. I’ll write more about this soon, but basically the idea is to glaze the walls of the kiln to help protect the bricks from the soda and to pre-season the kiln so less soda can be used from the first firing.
This is what the back of the kiln looked like before the firing:
And this is what it looked like after:
The back third of the kiln is usually has less soda than the front. I load porcelain or white stoneware clay bodies in the back of the kiln that do nice things with less soda to take advantage of this area. If I try to put my soda body in the back of the kiln it will be rough and dry. Not a nice look. I also load the kiln more loosely to encourage the flame to head back there. 

And this is the front of the kiln before:


And this is it after:


The kiln had mixed results for me. The pieces that I’m excited about I am really excited about. The ones that did not turn out so well are disappointments. But that is why I do soda. I’d much rather have the highs be really high and the lows be really low than to fire a kiln and say “oh, that’s just how I thought they’d turn out.” And when you have a kiln that you’re doing lots of experimenting with, those extremes are even more extreme. There will be lots of pictures to come, but I thought I’d give you a peak and some of the cups.

Please excuse my less than excellent pictures. I snapped them quickly in my studio last night as the sun was going down. Snazzy pictures will come in the not too distant future. I want to get better images of the test pieces so you can really see what’s going on.

I love how the pattern accentuates the form on these:

You might remember these masked mugs:

And perhaps you remember these too:
peace – hope – change 

And this is a little preview of some new pieces to come:

(I love this new clay body!)

Salt/ Soda Discussion Group

At NCECA I attended a discussion group that has carried on past Pittsburgh and is leading to some interesting post-conference disussions. At this year’s conference, the discussion group, Salt Firing Verses Soda Firing was led by Joyce Centofanti. One of the other attendees, David Hayashida, came up with the great idea creating an email list so we could continue our discussion and share recipes and techniques after we returned home. David put the list together and there was instantly a lot of information being passed around. Another participant, Pamela Theis, decided to take it one step further and create an Ning group (an social network site) that will allow us to continue to connect with each other, but to invite others out there who weren’t a part of the original group to add to the discussion.
So, if you’re interested in salt firing or soda firing, or even a hybrid, join the group and join in the conversation! It just began a couple of days ago, so we’re really just getting started.

Join the group Salt/Soda Firing 

I’ve been playing around on the site and found that you can upload photos and create this little slide show creator that you see below:

Find more photos like this on Salt/Soda Firing 

This is my page on the Salt/Soda Firing site, if you’re interested in seeing what you can do. I’m excited about the possibilities with this group. Soda firing is still relatively new so I think that a group like this that will allow us to share, trouble shoot and brainstorm can have a big impact. I hope you join us!

A Happy Soda Firing

I fired last week. When I’m done glazing, but before I load the soda kiln, I sit down and roll hundreds of wads for the bottom of my pieces. It always takes a ridiculously long amount of time. Time when I’m feeling a bit anxious about getting things done on schedule. When I was rolling my wads for this last kiln, it was a sunny day, and the morning sun was hitting them in the most beautiful way. I took this picture to share with all of you. My happy spin on a less than fun job.


Wadding Recipe
for the soda kiln (pretty standard) (by volume):
  • 1 part EPK
  • 1 part alumina hydrate
  • medium grog to taste (not really, but you know what I mean…)

I roll my wads ahead of time and put them in a plastic container (the ones from the local Thai take-out place are the best). Then I glue them to the bottoms of pots before loading (Elmer’s glue). Breaking up the wadding into steps keeps my hands cleaner and helps me avoid the problem of getting wadding where it doesn’t belong.

A shot of the front of the kiln. It was an interesting firing. I reduced the amount of soda that I added by about 25% or so.

(new) Soda Mixture:

  • 1.75 lbs. of soda ash
  • 2.25 lbs. of soda bicarb
  • 4 lbs. of whiting

Mixed together with 1/4 of a 5 gallon bucket of wood chips. Mix together well, then add enough water (while mixing) to the consistency of oatmeal cookie dough. I add it on an piece of angle iron through the ports on the front of the kiln when c. 9 is soft. (More on this in a future post.)

Below are some tea bowls that I got out of this firing. 


Why Soda Glaze? – by Maryke Henderson

Although there is more all the time, overall there is still very little written about soda (soda firing, soda glazing, vapor glazing, etc…). When I come across something that’s written specifically about soda, I get really excited and I want to share my find with all of you.


I recently came across this great article on the Australian ceramics website Avicam: Why Soda Glaze? It’s a lengthy excerpt from Maryke Henderson’s Bachelor of Arts research report from Australian National University School of Art in 2005. It covers everything from “What is soda?” and the historical background of soda to technical information on soda introduction and it’s corrosive effects on kilns. There are profiles of contemporary soda artists as well as a statement about Maryke’s own work.
The photos that I have included of Maryke Henderson’s work are from Avicam. They are elegant pieces that both intrigue me and make me very nervous. Enjoy the article and the beautiful images. When you’re done reading Maryke’s article, spend some time wandering around Avicam. It’s filled with interesting things to read and some really great pots to look at.


Surface Decoration Techniques: wax resist and underglaze/ slip inlay

I have been creating, soda firing and documenting simple straight sided cylinders with a variety of surface treatments for examples for my classes and this blog. The original idea was to create demos to show students that aren’t specifically “my pieces.” The fun result of this project has been that it’s given me an excuse to return to things long forgotten, or try something new.
Watch out for upcoming tutorials with lots of pictures and slip and glaze recipes.

Wax resist and underglaze/ slip inlay
A great way to make a clean line without too much mess, step by step.

 

Step 1: Paint slip on leather hard piece.
I used several porcelain slips (grolleg mixed with Mason stains) on Lillstreet Soda Clay 

Step 2: After the slip dries (no longer tacky), paint wax over entire surface.

Step 3: Using a small loop tool, carve in your lines.
Step 4: Paint underglaze into the carved lines.Step 5: Wipe away any excess underglaze.
This is a great way to get make a nice clean, sharp line in the leather hard stage.

 

The inside of the piece is glazed with a simple matte black glaze, and soda fired to cone 10 in reduction.
Because the line is inlaid, it’s protected from the soda and doesn’t “bleed” when hit directly.

 

Some close up images