Monday, February 21, 2011

Discussion & Analysis

Now that the euphoria of my first truly successful firing has, if not worn off (it may never wear off), at least settled a bit, it's time to review what worked and what didn't in last week's firing. This despite my lingering desire to just dance around in the kiln yard shouting, "Fecit!"

So, without further ado, this firing's Winners & Losers:

  • Winner: Amber Celadon, using local clay in place of Albany Slip. It was not exactly like the original recipe, but it's hard to say whether that is due to differences in the clay, or to interactions with the salt & soda vapors. But the surface was quite delightful, nice and fat, moving from opaque caramel to transparent espresso with differences in thickness. 
  • Loser: My new tenmoku. Well, loser is a harsh word. It's not that it is an awful glaze; only that it is not tenmoku. Too greenish-gold, too full of surface crystals, and too similar (but less nice) to Amber Celadon to find a place in my glaze palette.
  • Winner: Bauer Orange Flashing Slip. But we knew that. 
  • Loser: The upper rear corner of the kiln! Didn't quite reach temp. I don't see a good way to fix this, but I am investigating a work-around in the form of some ▴8 or ▴9 glazes. I am in glaze-exploration mode anyway, and will take it as a spur to try new things. 
  • Loser: Lipton Sig. Or rather, me, for either mixing it too thick (but how much thinner can it get???) or for applying it to bisqueware. From now on that is a greenware-only slip. It flaked off in a couple of places. I am not entirely sorry, as it means I get to keep a couple of the mugs, but that'll be quite enough of that, thanks. 
  • Winner: Satin Doll Black. (Recipe later: I'm too lazy to go look for it.) Fluxed in the cool parts of the kiln, looks great trailed and over my flashing slips, etc, etc. 
  • Winner: Latex resist! Got a post devoted to latex in the works. 
  • Jury is still out: 50/50 soda ash & red art clay, as a glaze surface. Also want to try 50/50 soda ash & kaolin. 

Anyblah. Next firing Saturday March 5. Lots to do before then!

Saturday, February 19, 2011

Pots for Sale!

Got some great pots out of the firing! It's definitely the best firing from this kiln (out of all two of them) and possibly my best firing ever. About 20% of the kiln were underfired, but the remaining 80% were all awesome. Not a stinker in the bunch. I am working on getting some posted for purchase (you can see the lot here) and getting the rest sorted for various retail outlets. But here, have a peek:

Purcahse this mug here!

Purchase this butter dish here.

Purchase this mug here.

Friday, February 18, 2011

Cone 8 Ash Glaze

Ash #35, Cone 8

Maine Marine Clay 81.6
Wood ash 10.2
Rutile 8.2

Just posting it here so I don't lose the recipe, like the millions I've written on the backs of envelopes. I'm planning to test this in the next firing.

Speaking of firing, the last was super-duper awesome! haven't had time to shoot photos yet -- will do that tomorrow, if it's sunny.

Sunday, February 13, 2011

Cone Forest

made up a ton of cone packs last night. I had the cones out anyway, so why not do a bunch of them at once? Avoid the whole oops-I-forgot-to-do-the-cones problem that plagues me. Unfortunately they are still a bit wet, but no worries: into the oven with them, at 170ยบ. That'll fix 'em right up, in about ten minutes. 

Saturday, February 12, 2011

Active Glazing

Habits die hard. I tend to do my decorating in the wet state: stamps, rollers, alterations, slip trailing. I had to make a concious effort this time around to leave the surfaces -- at least some of them -- smooth, to allow for more active glazing. In past I tended to just submerge the pot, and chose glazes that have nice pooling and breaking qualities, to work with all the impressed patterns I'd made while the clay was wet.

When I was a student firing atmospherically (salt, then; I knew little about soda. Was anyone firing soda, then? Probably. Just not at Edwardsville) I tended to glaze only the interiors, to let the flame do the work for me. I still like that look, and have used it on many pots that will go into the kiln tomorrow. But the results I am most eager to see are the pots which I covered with patterns, glaze over slip, glaze over glaze, or using latex resist. 

I'll be happy if the patterns emerge clearly, but I'll be ecstatic if, on some of them, a big, directional blast of vapor glaze softens or obliterates the pattern on one side, or even just a patch. 

Keeping my fingers crossed. 

Thursday, February 10, 2011

Merry Potter and the Secret of the Lost Amber Celadon

Albany slip, how I miss you!

I have this great recipe out of the Watershed glaze book: the best $25 I ever spent. It goes like this:

Amber Celadon

Albany Slip 35.87
Wollastonite 14.13
EPK 3.26
Gerstley Borate 3.26
Whiting 7.61
Silica 14.13
Custer Spar 21.74

Yellow Ochre 7.61

I looooved this glaze. In its original form, it's a warm buckwheat honey color, breaking to red where extremely thin. The gem jar pictured above is glazed in Amber Celadon, in its original, Albany-slip form. I tried the commonly recommended substitute for Albany slip, Alberta Slip, but the results were disappointing: a perfectly nice olive color (NOT amber) marred by alot of scumming. In truth I have found Alberta to be an inadequate substitute on other occasions as well. It appears to be noticeably more refractory than Albany, and often creates glazes that, while nice enough, are quite different than the ones they are meant to duplicate. So, boo, too-bad-so-sad, no amber celadon for Lori, right?

Not so fast!

My husband the genius had a typically briliant idea. We live in Maine, where we are surrounded by marine clay. It's an fine-particled earthenware, not great as a body clay, although some potters use it. (Doug and I memorably spent our camping honeymoon building tiny, duelling kilns out of available materials -- sand, rocks, stick, clay -- to fire a few pinch pots and figurines we'd made from it.) By itself it makes an extremely runny (at ▴10) slip glaze, dark brown. We decided to try it as a substitute for Albany slip.

Now here's where I run into trouble. We made two versions, the first a one-for-one substitution, the second leaving out the yellow ochre. One of them was exactly perfect, the other was nice, no scumming, but olive rather than amber. 

I can't remember for sure which was which. I think the one-for-one was the success, but Doug points out, why would we have tried the second way, if the first was perfect? (Answer: because he is always trying things just for the hell of it. Not that there is anything wrong with that.) Anyway, it's time to find out, once and for all: I have made up a 1000 gram batch of Amber Celadon, using dried & pulverized local clay as a direct substitute for Albany slip clay. If this works, I can see using local clay as a substitute in many recipes; Albany slip problem solved! it's a bit of a hassle, of course, to go collect it, slake it, strain out all the little rocks and sticks and insect bits, then dry and pulverize it; but worth every step if I can regain that yummy look. 

Will let you know after Sunday's firing how this works out. 

Wednesday, February 9, 2011


w00t! My new triple beam scale arrived today! Time to mix the glazes! I am not normally a big fan of glaze preparation -- ranks right up there with sales calls in my unfavorite pottery-related activities -- but I can get in a mood for it, and then, watch me go. I know it's time to change up my glazes when I feel no urgency to get the kiln open. That hasn't happened lately, of course, due to the suspense related to how the kiln performed; but a new kiln seems to call for a new glaze vocabulary.

My glaze mixing area is ourside in an ancient shed, because while my studio could be organized more efficently to accomodate it, I didn't really want all the muss and dust in the house. Silicosis and all that, ya know. So it's dark and grim, not to mention cold. But I've got my anticipation to keep me warm. 

Has anyone out there in TVlandhave a shino that works well in soda? My efforts along those lines have not gone well, coming out oatmeally and pale. I have one that claims to be for soda & will try it out but would love it if soemone would share one they could vouch for. 

Anyblah. Glaze mixing (and a trip to INFAB for a few more brick) tomorrow, glazing Friday, (gallery-sitting Saturday, unfortunately) and FIRING SUNDAY!!!!

Pics next Thursday. XO

Friday, February 4, 2011

Waxing Night

I kind of like waxing night in the studio, even though it's mindless. Or maybe because it's mindless. Just put on the Rovers, belt out "Cockles and Mussels" right along with them, and don't think too hard.

You know what I hate? That big obvious line of unglazed clay that happens when you wax too far down on a lidded jar. I learned to mark with pencil the perimeter of the lid, so I can put wax only where I need it. The glaze can come right up to the line -- after all, it's not gonna run up. The pencil mark just burns away, around 04. 

Thursday, February 3, 2011

February Goal Setting

  1. Fire off a glaze, next weekend.
  2. Make chowder bowls for Watershed! Their annual Chowdah Suppah fundraiser is coming up, and they've asked members of the Watershed community to contribute chowder bowls. I'm happy to help. 
  3. Refill my glazes. I haen't had a gram scale for a couple of months now, and have been skating along on the glazes I had mixed up, but those are getting low, and I'd like to add some new surfaces to the mix. My replacement triple beam should arrive this week, so no more excuses.
  4. Fill my wholesale orders, and supply my consignment outlets. They've been very patient with me getting the kiln rolling, but it's hard for them to sell pots they don't have. This month I should get everyone stocked up again. 
  5. Here's the great part: I have enough bisqueware now to fill two glaze firings, and maybe start on a third. I can finally stop playing catch-up, and start working on the more time consuming and interesting work that's been kicking around in my head. The topsy cake stands were a part of that, and I expect to be doing a lot more altered, assembled, and highly decorated work for the rest of the winter. 

Speaking of which, we're over the hump! Imbolc (Celtic for "Groundhog Day" [okay, not really]) marks the halfway point between the winter solstice and vernal equinox. Party like a pagan! Actually I just celebrated with some Raspberry Zinger tea.

Flame Dynamics

I just like saying that phrase.

Here is a thing I did not know: increasing primary air  (the air that enters the kiln through the aperture at the bottom of the burner) relative to secondary air (air that enters the kiln through all the other avenues, such as the burner ports themselves) shortens flame length. 

At the risk of boring the pants right off my non-potter readers, I found this great article about combustion and flame dynamics by Louis Katz at Texas A&M University-Corpus Christi. Read the article if you are interested -- I highly recommend it to anyone thinking of building a gas kiln.  I found a couple of take-aways relevant to my particular situation:

  • Katz mentions raising the bag wall as a solution to a cool top. I had arrived at that idea more or less intuitively, and it seems to have borne out if the recent bisque firing is an indication; but it's nice to have the validation. 
  • He also suggests pulling a brick from just under the arch, to create a sort of second flue, allowing the kiln to behave somewhat as an updraft, pulling the flame higher in the chamber. I never thought of that! Next time I fire, I will have to brick up the door in such a way as to make this possible. 

In other news, I purchased a new triple-beam scale from Ebay to replace my old one, which after 15 years of service flung itself from a tabletop, breaking an irreparable part. Got the new one for about 60% of retail, including the shipping. I considered a digital version, but, like the power windows in my car, it seemed like just one more thing that could go wrong and necessitate replacement. Give me a good old mechanical device any day. 

Wednesday, February 2, 2011

Yet Another Snow Day

See the blue blob, in the upper right? Augusta is right in the middle of the deepest, bluest part right now. And what am I doing? Unloading the bisque kiln! Well, after I shovel it out. Again.

Oh, yeah, there are other things I could be doing. I brought some high-grolleg porcelain home from Portland Pottery, because I got a bit of a yearning to make perfume bottles. But I am anxious to start waxing and glazing -- to get this next soda firing on the road! My eagerness is in part due to how very well the bisque fire went -- shot right up like a rocket. 08 was down six hours from when I finished the candle and started firing in earnest. And, also, I will need to shovel it sometime. Waiting until spring is really not an option.