Burning Question

So, a weird thing happened this morning. 
I candled my bisque overnight, but when I came out in the morning to turn on the burners proper, I found flame coming out of the primary air intake of the pilot. I had never seen this before & immediately turned off the gas - that's kinda my go-to move whenever anything unexpected is happening with the propane. I wish I had taken a photo to illustrate this post, but oh well. Probably anyone who would know the answer already knows what the primary air intake looks like.

The only difference I could observe between the pilot that was behaving normally & the one that was doing this unusual thing was the primary air intake was open a little wider on the odd one. That one was also a little harder to light last night. I don't remember opening or closing either of them but who knows? 

I spun the disk to close the intake a little more, so it matched the other, then re-lit the pilots. Nothing unusual happened after an hour, so I went ahead & lit the burners. 

Anybody have any ideas why that happened? I'm not gonna blow myself up, right?

Home Improvement

As anyone who lives in an old house knows, they always need something. Some needs are immediate: leaky roof! Furnace quit! Others wait until you have the time & money, or else the luck, to make it happen.

So it is with studio outbuildings. I have a weakness for old things, in the process of enacting the 2nd law of thermodynamics; it's hard for me to feel creative in a new, perfect space. Someone once said of the Watershed Center for Ceramic Arts, its own studio located in an old chicken barn: "It's conceptually impossible to mess it up." Which somehow (at Watershed, at least) makes it feel conceptually impossible to mess up. You can't make a mistake! You can only have a learning experience.

But I digress! What I wanted to tell you was, a combination of luck & time came together to provide for me a new door on my summer studio! The old one was a solid interior door Doug found in our cellar (repository of many unexpected things.) After 10 years the elements, alas, had had their way with it and it was falling apart.

In June I found an old mullion-window door at a yard sale for $5. Now, I have a few yard-sale weaknesses: small kitchen appliances are top of the list (NO LORI YOU DON'T NEED A SINGLE-HOT-DOG STEAMER) but old doors and windows call to me also. I mostly manage to resist, but this one was too perfect. The mullion panes and the very low price decided me.

Unfortunately for me there are many more things to consider when choosing a door than price! (And windows.) This door was too tall & a little too wide for any of the potential places I could use it, and the hinges were on the wrong side. Luckily we own a circular saw, and several screwdrivers! After making the necessary changes, I have a new studio door that lets in light, and allows me to see out even when its too chilly to prop it open. From the outside it lends the studio a beckoning cosiness: "Come in, Lori, make beautiful things, leave the turmoil of the world outside..."

In fact, I think I hear it right now! I've got butter dishes to finish and jaunty jars to begin.

Happy Labor Day, all! May all your labors be happy ones. And all your days.

MAKE IT STOP

My wheel has started to make a horrible grinding noise, like so:

The annoyingness ...that's a word, right? Hmm, maybe not. How about the "irritateousity?" Wait, no, "vexatiousness!" That is a word!...OK, the vexatiousness of this sound does not quite come through in the clip; it's so loud IRL that I can't hear my podcast while I am centering. I have a vague sense that it's something to do with bearings...anybody know how to fix this?

Uh-oh

Wouldn't you just know it? I feel like after 7 years together, this kiln & have have just hit out groove - I was getting good firings (almost) every time, coming in under 11 hours, good color, even soda...but when I went to unload this last firing, I see that one of the threaded rods that holds the angle iron skeleton together has rusted through.

The others are still in good shape - this was the one right over the door, so it got some heat and some soda every firing. Since it has broken, the walls have leaned outward somewhat, so simply replacing the rod is not really an option. Looks like I am going to have to take down the arch, and the two side walls, at a minimum- and if I am doing that I might as well re-do the back wall as well so I can replace the angle iron with a thicker gauge.

Even though this rebuild was not entirely unexpected, and even though mid-January is, business-wise, not a terrible time for it to happen, allow me to say: Damn it! Damn it! Damn it!

In other news, Sylvester - the kitty whose adoption fee we fully sponsored with the cat dish fundraiser - was adopted last weekend! I had hoped to do another cat dish fundraiser in a few weeks but of course the kiln rebuild is going to bump everything back.

At least the order I had in this firing looks good. I'm gonna need that $$.

And again I say, damn it.

Notes of a Mundane Nature

I almost typed "Notes of a Mudane Nature," which would have been sort of appropriate.

After much rumination ('cause that's what I do), I have started using SquaredUp as my retail page. I like the look of the custom-built shopping page better but it's so much quicker to just upload photos & write descriptions to the pre-made store that I went with that, for now. I've got enough on my to-do list without always doing everything the hard way. I went for months with nothing in the online store because I couldn't find the time to do it all.
I do still find SquaredUp confusing from the admin point of view (there's the admin page, and the editor page, and the dashboard page...which all do different things...OTOH you can easily create discount codes, which is a thing I wanted to do but couldn't through my paypal links. Here, I'll go ahead & do one for you guys: type in BLOG BUDDY in the promo code box if you make a purchase, and get 10% off!)  It's very easy to shop from, and - for no reason that I can see - my sales have been better than when I was custom building each page. There's more than one factor involved there, to be sure - this was after the long spell of nothing available online, so there may have been some pent-up demand; I think I got better at writing descriptions; my Facebook and Twitter audiences are larger; and so on. So I can't say SquaredUp is necessarily the cause of the improvement, but I am feeling a little bit superstitious about it now.

Even though I know superstition is bullshit.

[knocks wood.]

Now I just have to track down everywhere that I have a link to my shopping page and make sure to replace it with the new link.

Other notes:

It's spring, going into summer, which means I have a little more money than I sometimes do, which unfortunately does not mean I will be eating fancy chow and drinking fancy wine, or even buying a cool pair of steampunk boots. Lumber for new raised beds in the garden and an upcycled-bureau-turned-kitchen-island are more likely. In addition, some less exciting purchases are in my near future, it seems:

Thing one: Boxes, packing peanuts, newsprint and rolls of corrugated cardboard. I've located a new supplier to replace Uline, and they are local! Local is always a plus. I need to top up packing materials. EAB, Inc is located in Lewiston, about 5 miles from INFAB Refractories, where I get brick inswool and refractory cement for kiln maintenance. Which brings us to thing two: I probably need to get some wool, and some softbrick to spiffy up the kiln a bit, tighten the door and the spies, etc.

Thing three: This damn burner.

Would you look at that crack? How does that even happen, unless being a million years old is cause enough? Obviously all firing is off until I get this fixed. I've got a call into a welder near me, he has to look at it to know if he can fix it, if not, a new burner sleeve is on my shopping list. 😕 I'd much rather have a pair of steampunk boots.

Love is a Clean Burner

Remember my funky burner thing from last week? This one:

The consensus of my equipment-clever friends and readers was that the burner for some reason did not have enough gas pressure to create its Venturi effect. The burner was turned all the way up but the pressure definitely did not seem right, just before the flames appeared where they weren't supposed to be.

The possibilities included something -  a bit of rust or debris - blocking the tiny little orifice thru which the gas flows.

Luckily I never discovered whether that was, in fact the problem. On Monday night I had a conversation with my husband - I told him about the burner troubles and the possible fixes. You may think this is the dullest possible thing one could talk to a non-potter about, but Doug is an unusual guy. The physics of things interests him, and the kiln and burners are apart of that. I told him what our friend Tyler suggested as a remedy - taking the burner apart, removing the brass orifice plug, etc. He didn't say much, made some sympathetic noises - he knows how much I hate kiln maintenance.

When I came home from class on Thursday he had taken it apart, cleaned it all out, and put it back together! It hums along just like it should now. No more FLAMES BAD.

Now, he has taken a burner apart & put it back together before - I have an old one lying around. But that was years ago. He took apart the old one first, to remind himself, and then cleaned & thereby repaired my burner! It's sooty and gross and he barked his knuckles on the kiln brick getting it off the pipe, and now I don't have to do it.

Some guys bring you flowers and candy. Some write you poems.

Mine cleans my burners. 💗

Oh, and he writes songs. Check 'em out!

Flames Good, Flames Bad

A dramatization

Ugh, there is SO much to learn, in clay, so many new things to go wrong! The best that we can hope for is for things to go wrong when they don't do any harm, and by that measure I am a winner today.

I finally had a chance to fire the kiln I loaded last week. Candled just fine, no surprises...one of the valves was locked in ice, but I chipped/ melted it out, all good. Reached body reduction, all good...but when I went out to check if  ^05 was falling yet, I noticed one of my burners was behaving weirdly.

It's a measure of how dedicated I am to you, my darling readers, that I almost went for the camera before shutting it down, but then I thought: no, when propane and fire are doing unexpected things, the time to put an end to it is right freaking now. So I turned it off, then waited a bit and relit it - and it did it again.

The flame, which ought to come out the end of the burner and (mostly) into the kiln, was igniting way down at the primary air. I have never had that happen before, and I don't know what has caused it to happen, but in addition to just not being a safe state of affairs, it meant that a bunch of the heat was not going into the kiln. The firing was not going to proceed properly no matter what.

Luckily I have no urgency about this firing - it's always good to have pots but nobody pounding down my door in the middle of February. I have time to ask people way smarter than I am (Hi, Tyler Gulden!) what the problem might be and how to fix it.

So, now I have a sunny Sunday afternoon off, with just a tiny nagging worry that I might have to invest in a new burner. It's pushing 50°, and in February in Maine, it's criminal to let such a day go to waste.

Finally Finished!

I am just about breaking my arm patting myself on the back today for FINALLY getting the last course of brick on the stack. I stopped 2 courses short when I rebuilt last year, because previously the kiln drew a little too hard; but the new version drew not enough. Or sometimes didn't; some firings I had with the shorter stack were perfect, but two others were...well, let's say less perfect. I knew since the last firing, in December, that it had to be done - I couldn't keep rolling the dice. (Rolling the dice is a bad business plan. Write that down.) I was just waiting for enough of the snow & ice to melt away so it wouldn't be a suicide mission.

I'm a little nervous of heights. Not phobic, but maybe a little more cautious than your average person. Doug, on the other hand, spent his high school and college years doing tree work with his father, and has no natural fear of heights. He would have gladly stacked that last layer for me, but his lack of caution makes it even more stressful to see him just casually clamber around up there just like he's on the ground, than it is to just do it myself. He did come out and hold the ladder for me; I also felt like, if I fell, I wanted someone right handy to call 911.

I got lucky, and acquired the brick for free: Portland Pottery is rebuilding the bag walls in their large gas kiln. The brick were a little rough but perfectly adequate for my needs. On a related note, I am having an urge do grab some of those broken brick and collage all over them. They'd make good bookends, maybe. There's something so wonderful (in my imagination, at least) about the coarse broken edges and the decoupaged floral images.

But! One project at a time. Or, well: maybe two. Or three. Definitely no more than four.😀

Maybe I'll finish the staircase today, load tomorrow, and fire Sunday.

WELL THAT SUCKED

Pasty, lutefisk-looking pots

The Demon Crudebake has been at work.

Ugh, it's been so long since I had a bad firing I forgot how much it sucks. I was prepared for this one to be less than stellar; I knew the kiln wasn't firing right: climbing very slowly, and unevenly. When I shut it off I knew I'd have some refires in there...Wasn't quite expecting three-quarters of the kiln to be refires, but there it is.

Pots from the top shelf

So, here's the weird thing: it looks like a draw issue. The top shelf was good - juicy, even. Everything below it was as pasty as the denizens of Lake Wobegone. Even those top-shelf pots, you can see their bottoms quarters got less soda.

 Insufficient draw would make sense, because when I rebuilt the stack I rebuilt it two courses shorter, because it drew a little too hard before. Except, I've fired it since then, and it went perfectly. My firing in December was great! It's a mystery.

For now I'll be grateful that I got just enough pots to pay or the propane, and that I know (or hope I know!!) the cause and cure. I don't have anyone urgently waiting for pots now, so it is not a bad time to do kiln repair. I needed to rebuild the bag walls anyway, so looks like a trip to INFAB is on my list this week.

Fast and Easy

When you google "fast & easy" you get mostly recipe links. But one of the phrases google suggested to me was "fast and easy ways to get pregnant."

Um. I guess I thought the fastest and easiest was the one everybody already knows?

None of that has anything to do with this post.

I just wanted to say, this firing - the one that went off an hour and a half ago - was the fastest and most even firing I've done in this kiln. It was a ^10 firing - the ^6 ones are quicker, of course - and it took 11 hours. I candled overnight, but started turning the burners up around 7 AM, and it went off at 6 pm. That has never happened before!
I just changed one tiny little thing.

It's always scary to change something about the way you fire, if you have a way that works reasonably well, because if you try to improve on it, you can make it MUCH worse. And then you've lost a month's worth of work, because you just had to go experimenting!
In this case, this kiln has always fired unevenly - hotter on one side than the other. At first blush, you might say, Well, duh. It's got two burners on one side, and only one on the other. I guess that could be it, but it's a pretty small kiln - maybe 22 cf - and I have fired many kilns with two burners at the back and none at the front, and those can be perfectly even. So I was never completely satisfied with that explanation, but I didn't care that much, because the kiln was giving me good pots.

Not sure what possessed me to try and change it this time. I knew the kiln on the one-burner side always had much heavier back pressure, and I knew that a reducing lame produces less heat than an oxidizing flame, and this effect becomes more pronounced the heavier the reduction. The primary air was already all the way open, and I couldn't easily change the secondary air - the ports are hardbrick. But just today, I thought: the soda port.
My ports are low, so I can dump the soda mix right into the burner channel. Maybe low enough, I thought, to serve as a kind of secondary secondary air. Tertiary air?
Just pulling the brick didn't work; that side of the kiln lost all back pressure. Instead I found a fraction of brick and blocked a little less than half the port.

Perfect! I got a long steady flame, bright orange, no smoke, on both sides of the kiln.
Oh, I lied. I said I only changed one thing but I just remembered I changed another. I started to wonder if I could manipulate the flow of air into the kiln using the passive damper. Not just control how much, but where. So I blocked just a couple of inches far to the cool side of the damper.

Not sure if one or both of these adjustments was responsible, but the kiln climbed quickly and evenly right up through ^8. Got a little uneven after that, but not out of hand. I drew a line to indicate the position of the damper, and the brick blocking the passive, so I can find the sweet spot again.

Unloading this kiln on Wednesday.

On Second Thought...

While scraping and grinding kiln shelves, I turned on a burner to melt the snow out of the kiln. I bricked up the door to hold the heat in a bit, so the burner could do its job; and in doing so I was reminded: my castable blocks are in rough shape.

I've got a pail of refractory cement right here, and a trowel; I guess now is as good a time as any to make these repairs. It feels like I just did this, but actually it's been three years or so. It's gritty messy work, but kind of satisfying in a way. Leaves me feeling like I dun good. And bricking up will be so much easier when its done.

Since I am doing gritty messy work today, I might as well add "mix up door mud" to the list.

It doesn't change my firing schedule, because I can squeeze loading, candling, and firing the bisque into one day if necessary.

ETA: Yeahno. It's 10 degrees outside; if I wait until Wednesday I can load in 46 degrees. Call me a big baby, but I'm holding off. 

So, This Happened

Yesterday

Fortunately I love my work, because almost everything I do is work-related! Not absolutely everything, though; yesterday I was in a lovely wedding on a perfect summer day, blessed by a brief downpour. That's me, second from the right, as we do our half-assed Charlie's-Angels pose in the hotel room in our wedding finery. The bride - this bride, there were two - is my best friend from high school. Back then we talked about what sort of wedding we would have. My actual wedding was small and casual, but she went the whole nine yards. There was a chocolate fountain, y'all!

Today it's back to the mud, and the dust. Grinding kiln shelves, whoo-hoo! Then loading the bisque,

Today

and then firing, probably overnight. Squashing it all into one day because when I play, I pay. I need inventory for a new store opening in Belfast, Maine: Quench! More later: time to get dirty.

Kiln Shelves on the Edge of Forever

If I had a time machine - let's say it's a single-use, like those little plastic cameras they leave on the tables at wedding receptions - three possibilities would be in a tight competition for which single use I put my one chance at time travel:

• The obvious, of course: kill Hitler, or Pol Pot, or one of those other murderous bastards who really needed killing before they could commit their bloody acts; or
• Go back and tell my 1982 self, with my handful of graduation-gift money, to buy shares of Microsoft; or
• Go back to December 2013, and tell my last-December-self to just scrape and grind the kiln shelves then, because I am going to hate it ten times worse when I go to bisque at the leading edge of mud season, and find my shelves not ready. It's like have some really inconsiderate studiomate. Except it's me.

I'd probably go with option 3. I've watched enough Star Trek to know that messing with the timeline is dangerous business, so the one with the least far-reaching effect seems wisest. Also, it's doubtful I could pull off a murder, if I could even bring myself to kill someone who hadn't done anything yet; and getting my 18-yr-old self to listen about anything sounds even more improbable than the time machine premise of this whole exercise.

While I am waiting for time travel to be invented, however, I might as well be grinding these shelves.

I'm back. That is my least favorite job! I'm never excited to mix glazes, either, but once I get started I can kind of get into it. Shelf grinding is just, well, a grind.

I'm considering an investment: either some kind of power tool to make this go more easily, or replace all of my shelves with Advancers. The top half of my stack are Advancers already, and they are far far easier to clean, and don't need kiln-washing. Not to mention they are easier on my back.

Blue Flame

A week or so ago, I had the service guy from Suburban Propane come and clean my burners. I feel like this is something I should be able to do myself, but I'm still sort of intimidated by burners, and I wanted to watch somebody else do it first - and anyway he had to come out and check for a leak I thought I smelled while trying to fire a bisque.

I am astonished at the difference in the flame! I guess I thought it would be subtle: it's not. The flame is now almost totally blue, much quieter - I never thought of that aspect at all - and giving off far less heat outside the kiln. I never knew how much heat I was losing until I wasn't anymore. Seriously I feel like the whole Global Warming thing might be my fault! But all that energy that was going to make a bunch of noise and radiate heat into the air is now going to heat the kiln, so I am in hopes my firings will be faster and more efficient.

Here's the load before I bricked up the door. These pots are headed for Monkitree in Gardiner, the Portland Pottery Cafe, the Center for Maine Craft, and On the Main, and maybe a couple of new listings on my website. 

Burners and BTUs

One of my goals for 2013 is to do business more effectively, and more efficiently, in terms of time and money. Toward that end, I've been trying to make my firngs faster and more efficient. As part of the latter, I needed to figure out the current BTU needs of my kiln.

This is not something I've spent a lot of time thinking about, which makes me a typical potter idiot, just cluelessly happy-assholing around, using whatever burners come to hand, according to Marc Ward of Ward Burner System. Okay, Marc didn't say that, but I feel it was implied. Or else I am projecting - could be that, too.

Kiln material, size, and firing temperature all contribute to BTU requirements. (Backing up just a teensy bit: BTU stands for British Thermal Unit, one of which is the amount of energy needed to heat one pound of water by one degree Fahrenheit.) Hard brick kilns will require more energy than soft brick kilns to reach a given temperature for the simple reason that they are less well insulated and lose more heat through the walls. Larger kilns will require more energy because duh. A hard brick kiln will need 16,000 - 20,000 BTUs per cubic foot, to reach ^10; a soft brick kiln will need 10,000 to 16,000. Since mine is half-n-half - hard brick interior, soft brick exterior - let's thread the middle ground and say I need 16,000 BTUs per cubic foot to reach ^10.

So, now I need to know how many cubic feet in there; not stacking space, but the whole enchilada. What would be a simple equation - width x depth x height - is comlicated by the arch. How to figure that?

The equation looks like this: Width x depth x wall height + (2/3 x arch rise) For me this comes to just under 32 cubic feet. 32 x 16000 = 512000 BTU to reach ^10.