Friday, December 31, 2010

Goodbye, 2010

...You were a most amazing year. Not an easy one, by any stretch, but a good one all the same. Well, except December. December kind of sucked, but it's nearly over.

Since my Harrowing Highway Incident, I have had a change of outlook; not unlike Scrooge after his spirit visitation. Mine came too late for Christmas but I am nevertheless feeling quite festive, on account of being alive. Belatedly in the holiday spirit, I am full of ideas for next year, including this great gift idea: a bouquet of chocolate dipped pretzel rods, in a handmade mug.  I ain't just whistling "Jingle Bells;" I went and bought the ingredients and made some up, for photos.

Here's the recipe:

10 ounces pretzel sticks (Pretzel RODS)
12 ounces milk chocolate chips (or melting disks)
1/2 cup white chocolate chips (optional)
candy sprinkles (optional)
miniature M&M's chocolate candies (optional)
mini Reese's pieces (optional)
chopped peanuts (optional)

Prep Time: 30 mins

Total Time: 33 mins
1) Melt milk chocolate chips in double boiler or in microwave (be careful not to burn in the micro).
2) If you are using the white chocolate, wait until later before melting unless you can keep it over warm water.
3) Dip each pretzel rod about 2/3 of the way up in chocolate.
4) Lay on wax paper lined baking sheets, lining up the rods but leave a bit of space between them.
5) Allow to set a little, but not completely dry (while waiting, make sure your white chocolate is ready).
6) Dip a fork into the white chocolate and drizzle over the milk chocolate by gently swishing the fork back and forth over the rods but not touching them.
7) Place your sprinkles or candies on a paper plate and roll each pretzel rod in desired topping (or just sprinkle on).
8)Lay back on wax paper to set completely.
9) Tie up with a bow and give in a handmade mug!

Two things: I had better luck after I added a little bit of vegetable shortening to the chocolate, for a smoother coat. I later read that some people add parafin wax for the same purpose, and because it makes the chocolate harden better - important if the gift has to travel any distance, like, say, out of your kitchen. Kind of like adding CMC gum to glaze, for a stronger dry coat. 

Oh -- the photo at the top is not mine. My first efforts were too ugly. The ones in the photo came from this Etsy seller

My annual week of reflection has been postponed until next week, due to car, travel, and work issues, but never fear, reflect I will. It's worked so well so far!

Sunday, December 19, 2010

Back at the Wheel!

It's been weeks since I threw anything, outside of class demos. The long months during which I had no means to fire left me with plenty of greenware (now mostly bisqueware) so I am not making out of any need for inventory, but, blessedly, creative impulse. Throwing, altering, and assembling remain my favorite aspects of the ceramic cycle, although I am gaining an interest in more active glazing: brushing, trailing and using resists rather than plunking it in a bucket an hoping for the best. (I still do my fair share of plunking, as well!)

There's something very soothing about throwing and assembly, though. After creeping, creeping for months, ever-closer to the goal of a functioning kiln, it's nice to get that feeling of completion in seconds. The kiln-tweaking will continue, but I am on a sort of enforced hiatus, as I need to pay for the propane I've used getting this far, before I can fire again. I am hoping for another shot in January.  

By my own long tradition, I start back at the wheel with a board of mugs. Ah, mugs! Quick and endlessly variable, and if one doesn't work out, wedge it up and start again. 


Sunday, December 12, 2010

More Pots from the Firing

They aren't this blurriy, in real life. My photo set-up relies on natural light, and on a snowy day in December, that is a scarce commodity. It amazes me that they can be blurry even though I am using a remote shutter control: literally nothing at all is moving. Anyway, here they are.
Online sale here!

Exhibits A & B

Let me turn your attention to Exhibit A: it ran, yes, but the dominant glaze flaw here is crawling, caused by a cool bisque. This casserole was at the top of the kiln during the bisque firing.

And now, look to Exhibit B: A rutile blue glaze that has historically been stable to ▲11, fully down; in this case it ran like a mad bastard, in the bottom of the load. Ladies and gentlemen, I think we are looking at ▲12 or more.

Incidentally, I like both of these pots, though they will need some grinding, and so must necessarily be seconds. The flaws do not compromise the function in any way, so these will be bargains at half price: $22 each. 

So, nine up top, twelve at bottom...what's a poor potter to do? I had a good suggestion, from my dear friend Paul Mahoney of Friendship River Pottery: adjust the bag wall. I am thinking to raise it two rows or more, forcing the flame (and soda) upward before it can find its way out the flue.

I also plan on making better use of the passive dampers next time around.

Keep those cards & letters coming!

Saturday, December 11, 2010

The Good, The Bad, and The Refires

...and a handful of Wows. I'm not greedy; a handful of wows is all it takes to make me happy.

Hoping for the best while expecting the worst has become my secret default posture when it comes to the never-ending story of this kiln; so I was pleasantly surprised when I cracked the door around noon, and peering in, was greeted by a pot that didn't suck. Right there! In my kiln! How did that happen?

My hopes dipped when I removed the first big block; things were looking pretty dry in there. But wait! There's another non-sucking pot! And while there were a couple on that first layer that had cracked or crawled, even the unsatisfactory pots mostly didn't suck out loud; they were just dry, due, I suppose, to this being the first firing. I nearly doubled what would be a standard application of soda, but it looks like maybe I should have tripled it. Some pots, too, would have benefited from a solid cone 10, instead of the barely-nodding version we reached, but most on that first layer were just a little dry.

Now cautiously optimistic, I took a break to allow more cooling (mixed up some pizza dough in the bread maker -- Doug is a cham-PEEN pizza chef.) The first layer out, I removed another brick to reveal the next. Still some dry refires, but not as dry, not as many. ..and some really nice pots! Onward, next layer.

Bingo. This layer clearly didn't fail to reach temperature. In fact, when I get to the bottom, these pots look more like Cone 11+ than 9 or 10. I wish I had put cone packs in the lower part of the kiln -- didn't think of it until too late. This is useful information, though: I am dealing with a different problem than I thought. My troubles are not twofold -- slow firing and failure to reach -- but only one: uneven firing. The bottom probably reached temp hours before I shut it off. judging by the running on the few pieces glazed on the outside. Top cool, bottom hot...what do ya make of that? 

I'd love to take more photos, but it is going on 4 pm -- "dark o'clock" here in Maine. More tomorrow. 

Friday, December 10, 2010


...It worked! 

Well, more or less. At 5 am, with ▲10 beginning to bend, the burners began to lose pressure. I feel pretty confident that it was enough, as most of my glazes will go at ▲9, and these had the additional nudge of 5 lbs of baking soda and soda ash; plus a 1/2 pound of salt for good measure. 

So, good news and bad: the good news: well obviously. Also, the kiln appeared to be pretty even and easy to keep in a deep or light reduction. The bad news: this was a crazy-long firing, 15 hours, and in the end the cone did not entirely fall. (It still might have done; the gauges read that the burners were losing pressure, but the difference was undetectable just by observing the flames.) 15 hours is unacceptable, of course, but it now just seems like a matter of tweaking. Another foot or two on the stack, and proceed more quickly in the early bit of the firing, or...any other suggstions?

I plan to spend most of today in bed, reading The Physics of Superheroes. Unloading will be Saturday, photos Sunday, if all goes well.  

Thursday, December 9, 2010

Take Two

The propane guy is here, and you know what that means: today is the day I light the kiln and try again to complete a soda firing. I am far more anxious this time, for obvious reasons: if it doesn't work, I am out of ideas of what to try next and probably out of commission until March or so, after I get some of these expenses paid down. 

Anyway. Those are bad-luck thoughts! Start the first burner, brew up the rainforest nut, and we're off.

Sunday, December 5, 2010

Reach For the Sky

As of yesterday, the stack towers around 15.5 feet -- about 13.5 feet of interior height, which is the part that matters as far as heat dynamics are concerned. Doug built the upper four feet of the thing, with me just handing up bricks, due to my not-quite-paralyzing fear of heights.

I am nerving myself up to try firing again on Thursday. I am waiting for a propane delivery: not that I necessarily think I will need it, but I'd hate to see nine starting to go and then...What the hell?...Out of fuel! So for the first (yes, I'm still calling it the first: I never unloaded the pots!) firing I'd like to start with full tanks.

I am not sure how being fired to 05, then cooled completely, then refired, will affect the outcome. The pots from this firing will carry a big "Results not typical" asterisk, but I am of course hoping for the best.

For all my unsinkable optimism, the expense is starting to disquiet me. Brick, wool, propane...I was supposed to be done by now, and selling the fruits this Christmas season. But no matter: there is no going back, and nothing to do but just do it 'til it's done. Damn the torpedoes -- full speed ahead!

Sunday, November 28, 2010

Pick Myself Up, Dust Myself Off...

Start all over again.

Well, not all over. As you can perhaps imagine after reading this, I was pretty discouraged last night. Like a cork in the ocean, however, I don't stay down for long. I took some comfort in Nina's reassuring words, and started looking for my silver lining. I found a few:

  • I turned the burners off around midnight, at barely ▲05. I didn't bother to block the burner ports or shut the damper. When I went out in the morning, I still had color in the chamber. Whatever the issue is, it is not that this kiln is shedding heat. 
  • The laws of physics apply to me as well as anyone else. If I get the physical properties of the thing right, this kiln will reach temperature. There's no such thing as a curse.
  • The most likely culprit -- the stack height -- is the easiest fix. 
  • The necessary cost of not letting the possibility of failure daunt one, is, well, the occasional reality of failure, however temporary. It's a high price but a fair one.

My plan -- and I do have one -- is to leave the kiln loaded (I already blocked up the ports & damper), get a bunch more hardbrick, and build the stack another...3 feet, say. 

And try, try again. 

Saturday, November 27, 2010

Well, rats

Didn't reach temperture. I'm going to bed.

Today is the Day!

Finally! The event I have been working toward for months! I made the good coffee and put on cute underwear in honor of the occasion, but I had to switch out for thermals, because:

  • 5:16 am: It's even colder than predicted, and I am noticing that I should have dipped the kiln furniture. There is a rime of ice over the kiln wash bucket.
  • 6:46 am: How did it get so late? The first layer is loaded. Taking a break for breakfast: Thanksgiving leftovers. This seems so delightful to me that I am considering a Thanksgiving firing every year; but perhaps I am getting ahead of myself.
  • 8:00 am: I am of the lick-and-stick school of wadding -- how about you?
  • 11:30 am: Here is a moment of every firing that I hate: "Whew! So glad to be done loading! Now to light the burners and take a nap -- oh, crap. Still have to brick up the door." It only lasts a split second, but it happens every time
  • 1:00 pm Mudding up the door, and sealing with newspaper & slurry. Burners are on, wool over the arch.
  • Here's a little trick I learned in Minnesota: I start a fire in the stack while the kiln is cold, to get a column of warm air moving upward. This helps start the stack drawing, and is thought to prevent uneven heating early in the firing. 

And we wait. I'm off to take a bath, do some yoga, figure out something for lunch. ( I wonder if there's any pumpkin pie left?) I'll be back later when there's news to report.

Friday, November 26, 2010

Glazed & Ready

Here are a few pots for tomorrow's firing. I'd like to start loading now but don't dare becaue it is expected to be so cold tonight, and I don't want the pots to freeze; I have written off candling as a waste of money & propane, and an environmentally unsound practice. Unfortumately that means loading & firing happen all in one day, in cold weather.
Anyblah. Glazing is finished, and I can't start loading. Can't clean up until all the pots are out of there...Guess I'm off to read a book. Cheers! Hope your holiday was spectacular.

Sunday, November 14, 2010

And Now A Word About Kiln Shelves

I used my old shelves for the bisque, but they are not ideally sized for the larger dimensions of my new kiln, so in the interests of efficient firing, I'll need to buy some which are better suited. (It is a bit of wisdom here in Maine that "boat" is an acronym for "Bang Over Another Thousand;" it is starting to seem to me that the letters K-I-L-N stand for "Kick In [your] Last Nickel.") I won't have to replace all of them, but unfortunately my newest, straightest shelves are cordierite, also known as mullite. Sad to say, these are not appropriate for soda firing, as the soda vapor will attack the shelf material "aggressively" according to the nice man at Continental Clay, whose name I have forgotten. If I wanted to use them, I could coat the shelves on both sides with a high-alumina wash, but that sounds like a guarantee of little flakes of kiln wash all over the pots; fuggeddaboudit. Anyway, my options are:

  • Regular silcone carbide shelves. These are the black shelves you always see, usually warped. Heavy as all get-out, too. These are about $125 for a 12 x 24 shelf; I shudder to imagine what the shipping cost would be.

  • Nitrite-bonded silcone carbine shelves. These are those skinny (or skinnier), lightweight shelves with the little slits on four sides, called expansion joints, which are intended to prevent (or, really, delay) warping. As these are both lighter & cheaper than regular silicone carbide - and billed as no less strong - they seem like an obviously better choice. So obvious that I almost feel like I am missing something: why would anyone buy regular silicone carbide shelves? The nitrite-bonded are about $75 for a 12 x 24.

  • Alumina Kiln Shelves. These are billed as an economical alternative to silcone carbide, and they are cheaper: I found prices ranging from $34 to $83. They are an inch thick and weigh a bajillion pounds (or, you know, 22 lbs: close enough.) Still, the difference between $34 and $75 is not inconsiderable since I will have to buy maybe 8 shelves....Hmm.

  • Advancer. A girl can dream! These litte beauties weigh less than 10 lbs for a 12 x 24, and are only 5/16ths of an inch thick. Sadly, they are probably ("probably," she says, ha-ha.)out of my price range, at $175 each. I admit a great temptation, however: I am not particularly burly, and not getting any younger (looks can be deceiving!) and I hate to think of how I will load 20 years from now. Maybe I will hire a buff assistant. Yeah, okay, an assistant would be even spendier than fancy shelves, so maybe not.

Friday, November 12, 2010

Ware Not Air

First bisque!
Although I thought I had a crazy amount of greenware, I managed to fit all of the bone-dry pieces into the kiln. I have more capacity than I thought, so hooray for that. I just kept squeezing it in, because it takes almost the same amountof propane to heat ware as air. A couple of notes:

  • The door blocks fired without incident, much to my great relief. 
  • They shrunk about an inch, out of a starting length of 17.5 inches. So that makes the shrinkage rate of this castable recipe about 5.5 %. Not too bad, but more than I had counted on; so now I am going to have solve a gappage problem, by cutting or casting bricks to fit. (I could just print the recipe, but there is some silliness on the Goshen College page about all-rights-reserved, blah-blah-blah. I think it unlikely that they would even know about it if I did publish it, and quite laughable that they would try to protect a castable recipe -- for what? -- but I'll respect their preference, while snickering at the pretension.)
  • Um, just, YAY! I'm firing a kiln! For the first time in months! I finally get to see how this heat-box performs.
  • I am hoping for first glaze next weekend, but that's a mad lot of glazing in a short time, so...hmm, maybe Thanksgiving weekend?

Saturday, November 6, 2010

Block Party

After weeks and weeks and weeks of drying - so much that people stopped asking me if I had fired yet: it was getting embarrassing, like asking "Set a date yet?" years after the ring appears - it is finally time to fire these puppies, in what may be my last firing in Watershed's medium gas kiln. (Watershed has about a million kilns, one of which I think of as the gas giant -- more on that later.)

I can think of things that could go wrong ing this firing. I don't wish to enumerate them, for superstitious reasons, but the initials are "explode." I consulted with Kelly Donahoe, the studio assistant at Portland Pottery ( and a darn fine potter herself.) PP had a paid firing last month of some blocks much larger than these; a person was casting all the brick for their kiln. And you thought I was a glutton for punishment; I can't hold a candle to that chick. Anyway, Kelly told me that that firing was slower than the usual bisque, but not by much, just an longer overnight candle. 

My firing schedule looks like this:

  • One pilot on, door cracked, spies out, at 12 noon today.
  • Close door and spies at 10 pm. 
  • Turn on second pilot tomorrow morning early, Say, 5 am. 
  • Do the handy-dandy mirror trick.*
  • If that looks okay, turn burners on tomorrow at 12 noon.
  • Begin a slow turn-up schedule, similar to a glaze firing, without the reduction slowing things down.
  • Shoot right past Cone 10 to see 11 starting. 

*The handy-dandy mirror trick is simply holding a mirror up to the spy hole to see if it fogs up. If it does, the ware is still shedding water -- better stretch out the candle. 

Oh, speaking of gas giants: in addition to making a whole boatload of greenware, I also got some interesting reading done while waiting for water to evaporate. Among others, I read Death from the Skies!: The Science Behind the End of the World and From Eternity to Here: The Quest for the Ultimate Theory of Time. From one or the other of these excellent books, I learned that all the iron in the world - did I say the world? Scratch that: all the iron in the entire universe -- comes from the heart of stars going supernova. That's the only way iron, an element, is created. I'll never look at tenmoku the same again.

Saturday, October 30, 2010

Stillllllll Drying

Holy cow this is taking forever. At this rate I'll be lucky to have pots before Thanksgiving. Got a world of greenware, though.

Saturday, October 16, 2010

Trés Trays

No, wait, that means "very trays," which makes no sense. But "Beaucoup  Trays" doesn't sound as good, and "Many Trays," dumber still. So, let's go with A Whole Bunch of Trays. I like sets. Not necessarily matching sets, as in bowls or mugs, but dissimilar objects that are meant to go together. I've been making olive oil bottles, with handbuilt drip trays, which led to soy-and-wasabi sets, and S & P sets, and oil & vinegar sets, all with trays, of course. 

When I got done with those, I started on a butter dish jag. Not my usual thrown/assembled covered butter dishes; I wasn't in the mood for that much commitment. So I made a few butter trays (for the cat-free home, as they lack covers) inspired by my student Holly Johnson of Hurricane Mountain Pottery. Holly brought a couple of very simple handbuilt trays to class, and I had to try out the design. 

Notice the little cat feet in the third photo. Happy Jack is quite enthralled with my studio work; if he had opposable thumbs, he'd be my apprentice.

Unsurprisingly, to me at least, my results are quite different from Holly's; her trays are slimmer and more elegant, mine more meaty. I am making for the soda firing (please God, someday soon!) and have been working on foregoing much of the wet surface decoration to allow for the the action of the flame. I do find that different artists using the same techniques will nevertheless have markedly different results. 

After a bit, I decided I was after something even simpler: 

This one is just a fat tossed slab with the sides and corners pressed up. I am looking for a good turquoise Oribe glaze for soda, that I can brush into the interior, to make a nice contrast with the peachiness of the soda vapor glaze. Any suggestions?

Friday, October 15, 2010

Turn, Turn, Turn

To everything (turn, turn, turn)
There is a season (turn, turn, turn)
And a time to every purpose under heaven.

Doug & I finally brought my wheel up from the summer studio. I am always excited to bring it out, every spring, but having it inside is kind of inspiring, too. Also inspiring: I am running out of pots, and I have several requests from stores to bring more. I may have to do one more firing at Watershed.

The door blocks are taking an unbelievably long time to dry - they are still flexible! And one split, because I didn't properly unstick it from the board it was resting on. Once the blocks are successfully finished, I will post about that process; there is very little on the Web about how it's done, so this is an opportunity for me to provide a real resource. Part of my intention in blogging the kiln-building was to make similar projects seem less intimidating to anyone out there in TV-land who was considering it: if I can do it, and eff up along the way, and eventually get it right, well, it looks like anyone could. 

I should, of course, have cast the door blocks first, or at least as soon as I knew the final dimensions of the door, but I often back into projects, doing the parts I know how to do first; otherwise my not-knowing may become an obstacle to ever getting started. The way to begin is to begin. 

It's a crap day in central Maine, cold and rainy: perfect for sitting in my warm dry studio, throwing pots. Turn, turn, turn. 

Sunday, September 26, 2010


I would do the happy dance, but I am too tired. The kiln is done! Well, sort of. The door blocks are cast, and it will take them a few weeks (!) to dry, and then they will need to be fired ever-so-slowly; but as far as work, there is nothing left for me to do. That feels really weird. I keep thinking I should be doing something, but there's no work to be done.

Sure, I could tweak a few things. The stack could be a foot higher, and it could use an angle iron frame; but those aren't things that really need doing before the first bisque.

I will be posting an entry about the process of casting the blocks soon. That was the only part for which I had never even been present when someone else was doing it, during my prior kiln-building experiences, so I was flying blind but I think I got it sorted out okay. (We'll see. If I didn't, I'll show you that, too.) And thanks to a site called Lulu, I am publishing a book about this project. But mostly I will be spending the three-week drying time making pots to fill this kiln. Not today, though. Today I am gallery-sitting, and resting on my laurels. Laurels decay rapidly, but they sure are comfy while they last.

Cheers! Thanks for tagging along.

Friday, September 10, 2010

Plumb Straight

It's hard to see what's going on in this photo, so I will clarify: I tacked a string with a small weight (a "plummet") tied to the end from the rafter of the roof over the kiln. The purpose is to make sure that the stack goes up straight, as over 30-plus courses of brick, a slight list can turn into a giant, unstable one. As you can see, the 2 courses above the standard come in slightly; fortunately we hung the plumb line before it got any taller. Such simple technology; but nothing better has yet been invented. 

Though the exact function it was made for is unknown, the little stone being used as the plummet has a small groove carved around the narrow end, making it perfect to tie a string around.  That groove was carved over 3000 years ago. The rock was found on the Sebastacook River, a remnant of the people who lived there before Europeans came to this contintent. We've already brought this item to the attention of the archaologist at the Maine State Museum. who deemed it authentic but not particularly unique or interesting, which is why we still have it; but it pleases me to use it to plumb my stack, and imagine somebody millenia ago used it to make straight lines as well. 

Sunday, September 5, 2010

A Few More Notes About Castable

Sorry. Castable is my boom! It won't last. 

I started to apply the insulating layer to the arch today. I decided to mix and apply it one five-gallon bucket at at time, because bashing up soft brick is killing my neck and back, and I just can't do all that I need without interruption. 

I started out intending for the crushed softbrick particles to be about the size of coarse grog, but quickly settled for a gravel-sized bits instead, when I saw how dreary and, eventually, painful the task of crushing brick was going to be. 

They only sell Portland Cement in 94-lb bags. 94 pounds!! Come on. While there are lots of people who can easily lift 94 pounds, there are lots more who can't. I can lift 94 pounds, but, ya know -- I don't want to. I'm going to grunt, and stumble, and possibly lose my grip on the bag, and have to heave it to get it in place, and my back will hurt the next day. Whoever decided that 94 pounds is the optimal package weight in which to sell portland cement was obviously not thinking of women, but not just that -- there are lots of men who would have trouble, too. The entire lot was only $9, which I suppose is great if you need lots and lots of it, but really, who needs that much? I mean, besides almost everybody who buys portland cement. But what about all those -- I don't know -- hobby masons? They must get stuck with loads of extra cement. Me, I would have gladly paid $9 for 40 pounds of it, which I can easily lift. And now I am going to have to figure out what to do with the leftover. Which is going to mean lifting most of it, as I only need a few pounds.

Oh, and I am sure you already know this, but portland cement and concrete (which is conveniently sold in bags weighing as little as 25 pounds) are not the same thing. Concrete has little rocks and other crap in it, which we don't want, as we are going to add our own little rocks and other crap in the form of crushed brick and Hawthorn Bond. Cement is also not to be confused with plaster of paris, but that is a story for another day. 

Anyway. I mixed up a five-gallon bucket using parts-by-volume, 12 pts crushed brick, 7 pts Hawthorn Bond, I pt Portland Cement, 2 pts water. I applied it with a trowel to the west side of the arch, and will finish tomorrow. I certianly hope I am doing this right, as it is a sort of leap of faith -- if I've got it wrong, I'll probably eff up the work I've been doing for months now.

Either way, I'll let you know.

Saturday, September 4, 2010

And Now a Word about Castables

Warning: this entry will likely be hideously boring to non-potters. My apologies. Sometimes I note things here so I know where to find them!

Several words, actually. Turns out to be a more complicated subject than I thought, and very little information is available on the web about castables. It's worth noting that two of the three potters I consulted recommended commercial castable, specifically mizzou, if it is to be used for anything structural, like, say, casting the arch itself. I was able to score four (or four and a half, depending on how you look at it) recipes for insulating castable, such as you would use to put over a brick arch, to slow heat loss. I was quite surprised by how widely differing the recipes are.

Tim Cichocki, a potter from Norrgidgewock, Maine, used this recipe to insulate his groundhog kiln:

Equal parts:

  • Fireclay
  • Sawdust
  • Silica Sand
  • Portland Cement

From Tyler Gulden, Executive Director of the Watershed Center for Ceramic Arts:

  • 12 parts crushed soft brick
  • 7 parts fireclay (Hawthorn Bond)
  • 1 part Portland Cement

Tyler also offered a more durable, less insulating version:

  • 10 parts crushed soft brick
  • 9 parts fireclay
  • 1 part Portland Cement

From Reeder Fahnestock, Watershed's Facilities Director:

By weight

  • 4 parts Fireclay
  • 2 parts Alumina
  • 1 part sand or grog
  • 1 part crushed soft brick
  • 1 part Portland Cement

I found two castable recipes on the web from Goshen College in Indiana. This page contains a very thorough treatment of the subject, and more complicated than my needs require, what with all the laminating of the hot-face and insulating mixes. For my door, I am only casting hot-face blocks, and using soft brick outside them. The recipe that I need for this purpose is:

Door Brick Castable Recipe for Soda: Non-Insulating

  • 10 parts Kyanite
  • 1 part Ball Clay
  • 2 parts Fireclay
  • 3 parts Kaolin
  • P-grog (a high heat duty grog, sold by AP green)

I will be applying the insulating castable directly to the exterior of the arch, so of course there is no way to fire it; therefore Portland Cement is useful is persuading it to set. Portland Cement melts at ^10, however, so I decided to steer clear of any hot-face recipe that contains it. ( I know, I know -- lots of highfire claybodies contain material that fluxes at ^10, it all depends on the proportion, blah, blah, blah. I guess I just don't trust it. Plaster has never been my friend in the studio.) I am leaning towards the recipe which is heaviest on the crushed firebrick, for my insulating layer, mostly because I have  a whole boatload of rubble softbrick, and it seems a shame to waste it. I just have to pulverize it. 

Applying castable will also be a learning experience for me. Specifically I am wondering how long it will stay workable. Should I rent a small concrete mixer to keep it from setting? Or mix up small batches, only as much as I can apply before the set time. What is the set time, anyway?

If you have the answers to these or any of life's persistent questions, shoot me an email at , or reply in the comments.

It takes a village to raise a kiln. 

Friday, September 3, 2010

Boom Boom: Out Comes the Form

Burn it out? Or slide it out? Burn it? Or slide it? Burn or slide? These are the things I spend my hours wondering. How best to remove the arch form, now that the brick are in place. 

Burning is more fun by miles, but sliding is more practical, as someday I will need to rebuild the arch, and when that day comes, it would be nice to still have the form. So I'm sliding, if I can. It will still be necessary to burn out the frame holding up the form, so I get a little of both. Here goes!

Past the first ring of brick, which required a bolster in one place, but held...

Uh-oh. Damn that quarter-inch plywood! Damn my cheapskate nature.So, the form will not survive anyway, which means Plan B is activated: Burn that baby out!

I had meant to take photos while the form was burning out, but as it happened I didn't care to set down my trusty hose once the blaze began. The spaces in front and behind the arch forn were still unbricked, so the flame was not entirely contained. A couple of notes: 

  • If you live in town, as I do, inform the fire department and your neighbors what is going on. There is going to be a world o' smoke. 
  • We've had a crazy dry summer, so I hosed off evrything near the kiln, including the beams of the roof over it. The tongue of flame jetting out of the front opening would have licked the shed roof five feet above it if I had not been there  damping it back with the hose.
  • I only burned enough to remove the actual  arch form. The support that was holding it at the proper height is  (obvs) very charred, but I will remove it by hand, becuase of the whole out-of-control smoke and flame thing. 
  • A half-brick that had not even seemed loose when I was building dropped precipitously when I slid the form forward. I propped it up until the brick around it could sink the fraction of an inch I knew would occur when the form was no longer holding them up. Once the other brick sank and pressed against it, my woould-be dropsy brick was pinned in place. 

Next on the to-do list: castable. 

Sunday, August 29, 2010

2 x 2 x 2

Arch construction is easier with two: 2 people; a 2 x 4; and a 2-pound sledge. Here's Doug tapping in a brick for a nice snug fit.

I was frustrated (so what's new?) because the charts in the Olsen book did not include a combination of brick for my span, which was 31". I know that is a weird span, and it ought to be 31 1/2", as brick are 9" long, but remember I had those weird-ass bricks. I had a little flexibility in the span, but the closest width on the chart was 33".That seemed like too much to fudge, as it would create turbulence in the flame, and with it inefficiency and probably a hot spot.

But I used the numbers suggested for the 33" span as a starting point to purchase arch brick, and then stood them in a ring on end to discover what combination of what brick got me closest to 31", without going under.  This worked out quite well, although, as it turned out, once I placed them on the form, I hat to switch out a row of arches for another row of straights, because they were much tighter with gravity pulling them together. 

I do have two "loose teeth;" Possible solutions include custom-cutting (or grinding) a hardbrick; stuffing the gap with a tiny sliver of softbrick, which I would glaze (shino) on the bottom; or..well, I guess those are the only options. I might try both: the sliver of softbrick up front where it will be (relatively) easy to replace if anything goes wrong, and a custom-cut brick in the back. 

I have the week of Labor Day off from the IPTOG, during which I hope to complete construction at long last. My to-do list looks like this:

  1.  Repair 'loose teeth"
  2. Build form to cast door blocks
  3. Mix up hot face castable and strike the blocks
  4. A trip to INFAB, probably in a rented truck, to get the necessary brick for the stack
  5. Mix up and apply insulating castable on top of the arch
  6. Build the stack. 

Wow, it looks more daunting all written out like that; but on the other hand it is an observably finite list, as opposed to the nebulous "all that stuff" label I had been applying to my remainig tasks. 

I should have cast the door blocks first, as waiting for them to dry will push off the first firing by as much as two weeks. Guess I should move them to the top of my list. 

Think good thougths for me, that Maine doesn't get clobbered by Hurricane Earl, and also that this week stays out of the nineties. Brick dust stuck to sweat is itchy. 

Arguing Eggheads

These s & P shakers will be in the first bisque, tentatively scheduled for September 5th, and then in the first soda firing, Sept. 10, unloading the 12th.

Problem Solved!

Since the Great Welder Meltdown that happened Independence Day Weekend, I have been dithering about how to get the welding done. Well: not just dithering. The plumbing; the stack; the arch form; I worked around the problem for as long as I could, and tried to work up my courage to call Augusta Tool Rental. Everyone kept telling me welding was easy, I'd be able to figure it out no problem. Still, I was intimidated, so I put it off and put it off. 

Last week a friend of ours was visiting, an elderly gentleman of Ivy League background. I showed him the progress I had made on the kiln and explained the obstacle: welding the frame. I told him I was thinking of just renting the equipment and figuring it out myself, at which he shook his head: "No, no, my dear. That's for the other folks."

"The other folks, Bob?"
"Yes, the ones who do that type of thing."

There was no use explaining to Bob that I have always endeavored to be one of those other folks, the ones who know how to do things, and anyway I realized that as wrong-headed and snobbish as the comment sounds, he was right in an essential point: there are people for whom 16 two-inch welds of iron bits would be nothing, no more difficult than throwing a board of mugs is for me. I knew welders existed, of course, but that was when the lightbulb went on that it makes no sense to struggle and dither when I could just get it done, in an hour. It's okay to have help.

Wednesday, August 4, 2010

Arch Nemesis

I so wish I had a camera! The arch form is complete, and it is such aa appealing object, itself.

I had one false start, when I decided I was very very clever and would avoid the tedious assemblage of slats by using a length of flexible hardboard bent over the form. Yeah, don't do that. The board is not THAT flexible, and tacking it down was almost impossible -- it kept pulling nails loose, and the flat sides weren't flat. Oh, for my camera! The result would have been funny instead of murderously frustrating if I had known I could share it.

Anyway the form is complete. Hopefully I will be able to get some shots of it before its duty is done.

Canoeing today, if the rain stops!

Sunday, August 1, 2010

How Things Stack Up!

Obstacles, obligations, and temperatures in the nineties conspired to make July a bust for kiln-building. No lie, the entire month was inchwise. And our camera went bye-bye, so you'll have to take my word  that it's August now and I am back on track. On the downside, I am bailing on a family vacation (well, half of it) to get there. I feel like a bugturd about it, but I was just so frustrated with everything taking priority: work, family, classes, vet appointments, gallery-sitting, everything.  All important stuff, to be sure, and most of it not optional, but at some point I had to declare that the kiln is important, too; otherwise it just won't happen. (See: Housepainting, three-quarters finished. )

Technically I got back on track yesterday, the very last day of July. I started building the stack finally, and while there is, predictably, some half-assery going on, I made good progress. Is it a bad thing if my tolerance for half-assery rises geometrically as this project wears on? I've reached the damper, for which I need a lintel brick that I don't have (natch), so I am going to build the arch form today, instead, and head to INFAB tomorrow. I need some more arch brick anyway. 

I was surprised to discover that INFAB doesn't sell skewbacks, so my choices are 3: have them shipped from Sheffield, MA (although, surely, now that I think on it, there must be another supplier of refractories closer than that: I can't believe that no one in the entire Boston metro needs kiln brick); make them out of castable (cheap and doable, but one more step in a project with too many steps already); or have INFAB cut them out of straights. So I guess I've got some phone calls to make, about pricing. I only need about 8, so how much can it be? 

Anyway. It looks cool and dry today, a perfect day to build an arch form. Feeling only slightly guilty, I will wave my family goodbye and get moving!

Saturday, July 10, 2010

Quick Kiln Updates

1)Like so many things, plumbing turns out to be not half the big deal I thought it was going to be, It helps that Home Depot will cut and thread pipe for you, at a ridiculously small price. (I did have an amusing incident at the register, when the cashier accidentally rung up my 37 inches of pipe as 37 feet. She was a little huffy and said the tag was written wrong, but really, does this look like 37 feet of pipe?) Any case the plumbing is ready to go. If I'd known it was so easy (and so cheap!) I might have repositioned the two burners that remained as they were in the old configuration, but what I've got will work just fine. Just storing it away in my Big Book o' Lessons.

2)We had to fire our free welder, for repeatedly (and persistently, after several requests to stop) making racist and homophobic remarks. You think you know someone...Anyway. That sucked, but some things are more important than kiln building. (Not too many, but some.) We have another friend who can help if we get ahold of him; if not, I do know a professional I can hire. Welding is not a task I'd try to learn on the fly. I am kicking myself for not learning to weld during either my undergraduate or graduate programs, when the metals sculpture studio was right next door. (I wasn't too interested in the metals, although I remember having an interest in one or two of the sculptors...)

Salad days at Watershed today! Hopefully photos tomorrow. 

Saturday, July 3, 2010

Get it Right the Second Time

I had to tear down one wall of the kiln this week, due to a 'clever" design change I made to the flue. I'm not sure what inspired me to re-work my original flue design, but I suspect that it was a desire to avoid having to manually cut soaps (lengthwise halves) from 3-inch brick. The second design looked like this:
I built all the way to the top layer of straights before I realized the problem. As you can see, if you follow the vertical line of the edge of the flue upwards, it butts right against the soda ports. Which means the soda ports will be hidden behind the stack wall. Nice going there, Ace! I spent a day trying to figure out how to rework the stack or the ports before I decided that was too much power to give to a mistake: better to correct my error than compound it.

So Thursday I took the back wall down, built the flue as I should have in the first place, soap-cuts and all. By this time I am an old hand at cutting hardbrick with a chisel, and though it was slow going it wasn't really difficult. 

Lessons learned: 1) Don't make design changes on the fly; and 2) the difficulty I am trying to avoid might not be the big deal I think it is. 

Saturday, June 26, 2010

Mother, Should I Build the Wall?

Ooops, too late, already did it! The walls are built, thirteen courses of three-inch brick. My next step is acquiring angle iron and tie rods, and welding the exoskeleton. Well, not welding it myself, exactly, but getting a friend with a portable welder to come out and do it. Portable welders must not be too uncommon, as I know two guys who have them, who have expressed a willingness to help.

When I started figuring out the stack, I discovered two things: One, I had placed a soda port too close longitudinally to the flue, such that the stack will block it; and two, the Fourth Law of Kiln Building, which states: However many cinder blocks you have, you need two more.

I finished my efforts last night in time to attend a reception at the Center for Maine Craft, a preview of the plates that will be featured at Watershed's Salad Days gala. (That's coming up July 10th -- hope to see you there!) I love those events for more than just free wine: I learn so much talking to other potters. Last night I came home with two helpful kiln-building ideas:

1) I could probably get away with building the arch out of superduty soft brick, despite conventional wisdom that the interior of a soda kiln must be entirely lined with hard brick. It is certainly true that the lower half of the walls take almost all the abuse; has anybody out there had any experience with this? I'd love to use IFB instead of hard brick, for the obvious reason of its (much) greater insulating qualities, but also because it's cheaper and easier to work with.

2) A potter whom I greatly respect mentioned that he had heard of people glazing the interior of their soda kilns, either with a very stiff glaze like a shino, or perhaps with a wollastonite glaze. He wasn't ready to vouch for this technique, not having tried it, but I am quite intrigued by it. It appeals to me on an aesthetic level -- remember, I am enamoured of kilns as beautiful objects -- and also because it seems like one of those ideas that is so obvious that you wonder why it isn't standard practice. I can't think why it wouldn't work. However, there is a world of difference between "Lori can't think of a reason" and "There is no reason" so again, I'd be delighted to hear from anyone who has seen this done.

It's a gallery-sitting day for me. so I won't make any progress today, except the mental work of figuring out my soda port problem. But do me a solid: poll your potter friends and let me know if anyone has tried either of the ideas I mentioned, and how it worked out. You can comment here or email me at with any news. It takes a village!

Sunday, June 20, 2010

Take a Header

The header row is a row of straights. Get it? Header-row? Hetero? Come on! That was funny. Oh. Heard it?

Anyway. The hricks in the header run perpendictular to the line of the wall, to tie the two walls together and thereby strengthen them. One should really place a header every fifth row, but because there were some many cuts, seams, and related goofiness on the rows containing the various ports, I wanted at least one solid row before the header, or it can't do its good work. In my case, because this will be a soda kiln when it grows up, everything on the hot face must be hard brick, so excepting the corners, the entire header is hard.

Reaching the header is a kind of milestone, and depending on the weather, I am inclined to take the day off and do some gardening; my other passion for which I have had precious little time. The next post might be of the see-what's-blooming variety. 

Friday, June 18, 2010

A Few Notes

It's starting to look like a kiln! Tomorrow I will finish the layer above the burners, which contains the burner lintels, and two soda ports. After that it is smooth sailing until it's time to build the arch; at which point I have another anxiety attack scheduled. The burner ports and the flue all look gigantic to me, but they are appropriately sized according to Olsen, and anyway it's easy enough to make a port smaller if need be.

Some mistakes I could have made, and didn't:

  • I almost forgot to leave a space between the cinderblocks under the stack to accommodate the propane pipe. Fortunately I noticed before I started building the stack, so it was no problem to correct.
  • All of the ports need to be surrounded by hard brick, not IFB. The soft brick I am using is only rated to 2300°, because it is cheaper, and more than sufficient for the exterior. However, the burner ports are going to exceed that temp. What I almost forgot was that the soda ports need to be hard brick also, because a) soda deteriorates IFB, and b) sliding a bit of angle iron, or even the nozzle of a sprayer, into a port at cone 9 is an excellent way to get a bunch of little pieces of grit stuck to the pots. 

While I was at INFAB purchasing the extra long brick to make the lintels over the flue, I asked the nice man to chop one of my own 3-inch brick in half. I didn't even have to play the cleavage card! (Just kidding. That card is a bit tattered these days.) He agreed so readily that I wondered if I should have asked him to cut a few of them; but that would have been pushing my luck. 

So anyway, tomorrow I will be cutting hard brick with my trusty chisel. Only a few...but that's a few too many. It's supposed to be 87° out, so I might take the afternoon off and head down to the river for a swim. 

Thursday, June 17, 2010

Aggravation, and a Happy Ending. I Hope.

I hate Lewiston. Sorry, all you Lewistonians, but it's true. All of the streets in Lewiston are one way. Worse, they are all one way in the same direction..

Okay, so that's not literally true, but sometimes it seems that way. I headed off for Lewiston Refractories this morning thinking I knew where I was going. I hadn't been there in a few years, but I knew once I got to the general area, I could find it. HA!

It wasn't where I thought it would be. It wasn't a little further along than I thought. It wasn't the next street over in any direction, and nobody in the neighborhood ever heard of it. But I didn't imagine it; I still have some inswool I bought there in 2006. I remembered that they changed their name to INFAB, and searched a little more. 

Finally I gave up and went into the offices of Oxford Networks, an internet service provider, and asked the receptionist to google it for me. Ha-ha, funny joke, they'd moved! I'd been driving around Lewiston in the traffic and pouring rain for almost an hour and I wasn't even on the right end of town. 

When I did find them, it turns out they don't sell 3" brick. Is that really such a weird size? The fellow there told me I couldn't get it anywhere in New England, they had to special order it out of Maryland. Which they weren't inclined to do for eight soaps, and a couple of stretchers. 

So now I am back home, figuring out a new plan. Sincce I don't want to dirve to Maryland, and I have plenty of 2 1/2 IFB. I think I am going to buy the additional hard brick I need and build the burner port/ flue layers of 2 1/2 inch brick. I was going to have to buy more hard brick for the stack anyway. The goofiness factor just went up a notch, but hey, there are no kiln police, right? As long as it works, I don't care if it looks like it was built by the cast of Ringling Brothers. I am off to re-do my brick count. 

Of course, this all means I will have to return to Lewiston tomorrow, and I hate Lewiston. It'll be a little better now that I really do know where I am going.

Saturday, June 12, 2010

Stupid Kiln Bricks

The Tenth Rule of Kiln Building States: No matter what, you will end up half-assing something. (The Sixth Rule of Kiln Building is "Have the right equipment." I haven't yet formulated the others, although they are there in my brain, swimming around, disarticulate.) Is it bad if my half-assery begins before the burnerport layer?

Despite all my careful measuring, levelling and squaring, the first layer, all soft brick, is a half-inch wider in both directions than my second layer. This only matters on the corners, where the angle iron will need to come all the way down past the top edge of the cinder block in order to accomodate a tie rod which will run below the stack. At least, I think that is the only place it will matter, so I nipped off the end of the corner brick Cutting soft brick is a breeze with a coping saw. Cutting hardbrick is a different story, requiring lots of  patience and a good chisel, or else an expensive chop saw. (Of the tree, I possess only the chisel.) In fact I re-laid the hardbrick floor layer when I was halfway done, to avoid having to cut hard brick. Undoubtedly I will have to do ti at some point, but I'm not going to do it when it can be easily avoided. It's not what I would call recreational.

Each layer seems to require me to stop and cogitate for a while before moving on to the next. In theory that should prevent re-dos like the aforementioned; in practice I think some re-dos are inevitable. Maybe that is the 11th rule of kiln building.