Soda Pots

Here are some pieces from our recent soda firing. I lied, I am not going to post the ugly ones, after all. All of these pieces are for sale at http://finemesspottery.blogspot.com

This Week in the Studio

Saturday:
• My day at KRA
• Price, pack pots for Ember Grove

Sunday
• Mop!!
• Make 22 Cat Urns for order
• Photograph pots from Soda Firing
• Mix test glazes

Wednesday
• Deliver to Ember Grove
• Trim Cat Urns

More Thoughts on Soda Firing

After reading the previous post, my good friend and former studiomate Mary Jo Schmith, of Front Avenue Pottery and Tile in St. Paul, Minnesota, offered her thoughts on soda firing, along with some photos of her soda-fired work:


FYI...I fired with soda for 2+ years here at the shop. I tried many different ways of introducing soda in to the chamber, including dumping it in the bag wall with an angle iron rod full of soda bicarb. I finally used a sprayer because
It did NOT leave large chunks of soda on the pots
it did NOT leave large chunks of soda on the kiln furniture...which stinks!!
It DID give the very best distribution of soda thru out the kiln....no dry spots.
Using a regular garden sprayer
4 1/2 lbs baking soda dissolved into 2 gallons hot water in the sprayer
start spraying at cone 8 bending
Spray into each port 12-15 seconds each port.
I think I went around the kiln 2 or 3 times & then waited for cone 9 to bend.
Start spraying again at cone 9
again at cone 10
Keep spraying until all liquid gone.
I drilled 4 new ports into the kiln walls.
one on each side of the kiln, just above the top of the bag wall and about 1 foot away from the burner port.
one on each side of the kiln door, just above the top of the bag wall.
I also sprayed into the peep holes in the door...the ones used for cone spy.
Total of 6 ports to spray in.
The placement of spray holes was clearly to spray soda solution in to the bag wall/flame so the solution would flow with the flame.

The brass tip of the sprayer will most likely eventually melt off so always had a spare tip, including the entire replacement wand!!!

I started with 4 1/2 lbs baking soda PLUS 1/2 cup salt but stopped using the salt entirely because it made the pots dark...dark brown, rather than gently flashed with color.

I also tried placing pots full of soda bicarb around the kiln chamber on the shelves with the pots. This was not all that successful at creating surface BUT DID make a huge mess on the shelves, ruining them!!!!!!!!!!!

Here are a couple more images:

Oh, No!!!

...Not another learning experience!

Actually I am exaggerating. we got some very nice pots out of the firing. Also some stinkers, at least I did. Hubby seems to lead a charmed life in that regard. Here are a few pots just after unloading:


Doug's Pots














My pots. I am very pleased with the toasty brown pieces in the foreground -- it's the pasty white ones farther back that were disappointing. I was hoping for a fleshy salmon pink. That's where the learning experience comes in: I won't be using that clay body naked again. I'll have some better pics of individual pots later, the good, the bad, and the ugly.

Up Next: Soda Firing!

I spent Wednesday waxing, glazing, and mixing wadding and soda salad (moron that later!) for the soda firing. Wadding is used to prevent ware from sticking to kiln furniture, and is used in salt, soda, and wood fired kilns. I use a pretty standard recipe:

4 lbs kaolin
4 lbs alumina hydrate
2 lbs medium grog

I wax the bottoms of the pots, because the wadding sticks to wax better than to bisqued clay. This works best when I am loading each piece immediately after wadding. When circumstances have required wadding ahead of time, such as for an enormous kiln load, or for a large-group firing, it's better not to wax, and instead to use a little dab of Elmer's glue to keep the wads in place.
It should be noted here that I haven't fired a salt kiln since graduate school -- I ain't saying how many years ago that was -- and I haven't done a soda firing, except as a workshop participant, ever. So I had a lot to be nervous about, and there were a lot of mistakes waiting to be made. Let me tell you about one, and I hope it is the worst one:
I had some doubts about how to introduce the soda. I've seen it sprayed into the kiln, but that seems like a lot of rigamarole and equipment; I'd heard of people making "burritos" out of soda ash and wet newspaper, and that seemed like a good way to end up with a lot of dry spots in the kiln. (Dry spots being places where the vapor didn't reach, which thus got little or no glaze. What I wished for was a way to introduce soda the way I used to do salt: Place it along the length of an angle iron, stick the iron into the port, and dump the material into the flame. I found it, finally, on Emily Murphy's page. Emily recommends mixing soda ash, bicarbonate of soda, and calcium carbonate with wood chips and water to make a paste the consistency of tuna salad, and the spreading that on an angle iron to insert into the kiln. What she didn't say, but I should have known, was not to add the water until shortly before using the mixture. I mixed it all up on Wednesday, and by Friday it was a concretized mass. The soda undergoes a chemical reaction with the water turning it into hard crystals that I had to break up with a big scale weight I found lying around. That stuff stings the skin, too!

Another unexpected element was a late season snowstorm. Actually, firing in the snow is not that bad. What really stinks in loading in the snow. Unloading is Sunday -- or Saturday night if I just can't wait.

To Do List for Firing

Glazing in progress.

Wednesday
1. First thing after coffee: Load bisque
2. Make conepacks: 2 low, 2 high
3. Wax soda pots, glaze interiors
4. **Mix wadding**
5. **Mix soda blend**
6. Fire bisque
7. Mix tests
• 50/50 red art & soda
• 50/50 kaolin & soda
• Bauer Orange flashing slip

Thursday
1. Wad, glaze & load soda kiln

Friday
1. Fire soda
2. Pick up pots at Camden

Saturday
1. KRA
2. Unload Soda

What's Happening This Week

Bone-dry mugs awaiting bisque firing




• Thursday: Throwing vases
• Friday: Travelling for Easter weekend; scouting stops in Portsmouth & Newburyport
• Saturday & Sunday: Visiting family

Next bisque: wednesday March 26
Next glaze: Friday March 28, unload Saturday. Watch for new work for sale at our shopping site !

Firng To-Do List

This is the only lidded jar of my recent batch to survive a kitten attack. The last bisque before the soda firing is Wednesday the 20th, due to Easter travelling, so there isn't time to make more. I will squeeze in a few more mugs. which will need to be finished by the end of today.

The soda firing happens Friday March 28th. Here's what needs to happen between now and then:

• Mix wadding, to prevent pots from sticking to the kiln shleves.
• Make soda mixture
• Wax pots & glaze interiors
• Mix glaze tests

Four Days in the Studio

Thursday: Lidded jars & Mugs
Friday: Trim Lids, handle mugs, decorate.
Saturday: My day at KRA. Straighten the studio to get ready for glazing.
Sunday: Glaze interiors for soda firng.

Lidded Jars

I admit I don't have a particular use in mind for these. Too big to be sugar bowls, too small to be canisters. Any suggestions?

What's going on in the Studio

Friday: Gluing hardware onto cabinet pull knobs!

Saturday: My day at the shop: Grand Re-opening tonight!

Sunday: Finish knobs & make some lidded jars.

Square Plates!

Despite their shape, these are wheel-thrown plates. They begin their lives round, as bowls, and then I cut away arcs of the rims to create the square. The contrasting color is trailing slip -- basically a mixture of white clay and water, which must be applied while the piece is still wet. The decoration thus acheived is both visual and tactile, as the slip will maintain its dimension even after firing.
Next glaze is a salt-firing planned for the end of March, and these will be in it.