Monday, June 30, 2014

Poor Big Anthony

I believe I've lost count of the firing attempts of this little kiln o' mine.

Wait, let's pull out the firing notes.  Ah, yes.  Eight.  And I believe I am further from my goal than I was with the first firing.  In fact, after this last one, I declared the fella Dead.

Not him, really, but the burners.  They backburn, immediately upon ignition.  A thin blue flame travels most of the way down the throat.  (And I've been instructed to just use them this way.)  This creates an incredible amount of heat - even the gauges and valves radiate enough heat that I'm convinced they're damaged.  Far more heat comes from this system than the kiln walls.  I'm certainly not going to fire those burners again.

I added two more 100-lb propane tanks this time (so now running on four), which got me past the 1974° wall I was hitting before.  However, this time I still topped out - at 2175°.  Was able to reach anywhere from cone 4 to cone 6, but oh it was s.l.o.w. going there at the end.

I'm convinced, without a doubt, the chimney is the issue.  The heat (oy, is that chimney hot to the touch!) and soda (I doubled the amount I sprayed, and there's absolutely no evidence of this addition) are both being sucked out.  But what the heck do I know?  As I have been told, I'm trying to learn to drive a car by reading a book.  I need someone here who knows.  However!  These firing helpers are impossible to find.  Impossible.  Oh, the far-reaching ideas I've had of someone - anyone - coming to help.  Oh, the people I've begged.  Nope.  Not happening.

So I figure my choices are these:  1. New high-pressure Venturi burners and re-built chimney  or 2. Throw in the towel and build a real kiln, from tried-and-true plans, in the country.  In fact, bring the kiln designer up here to not only build it properly, but fire it once, too.

The first option is an incredible gamble - there's still no formula for the proper size of the chimney.  And oh, the money to spend on burners, for such a gamble.

The second ... Well, you need to have land in the country in order to build a kiln in the country. Oh yes, and $12K-$15K or so for said kiln.

BUT!  How about a third idea?  (There are always more options, if you dig deep enough.)  How about switching to power burners?  And/or redesigning the kiln to be a proper downdraft?  And, with power burners, won't the chimney be far less of an issue?  And there might even be some formulas for how to size it properly?  And didn't someone mention to me, many months ago, that I could perhaps build my own power burners?  On the cheap?

I'm working on this third option.  Nine months and eight firings later, I'm still full of hope for this little kiln.

In the meantime, I did admit defeat on some levels.  The electrician arrives this week to hook up Helga, the computer-controlled electric kiln.  This initially made me kick, scream, and cry.  But I'm thinking now it will come in quite handy, both for one specific project and as a bisque kiln (tumble-stacking might even work then, eh?).

Also in the meantime, my pots are slowly becoming a bit better on their own, outside of firing.  These three I do not particularly love, but they did come out of the kiln properly fired.  The rest are dry and white, having not reduced and not received a lick o' soda.



August will hopefully bring good things.

Monday, May 19, 2014

Handles, Handles, Handles

Halo!

I'm currently firing the kiln.  Inside are 40 or so mugs.  I tried to play around with forms - not as greatly as Emily Murphy showed us a couple years ago, but I did play with a few different shapes.

More importantly, I focused on handles.  My handles have, historically, sucked.  There were varying levels of bad, really, but usually they just sucked.  I had no idea how to make them better, back when I did this years ago.  However, now I have the power of Ye Olde Internet.  Scary, really, the time I've spent staring at other people's handles, scratching my head over just how did they do that?  Made a little Pinterest board of fine handles, even.  Turns out there are as many types of handles and methods of forming handles as there are potters - and I'm trying to nail down just what I want to make, and how.
  They're very much not yet where I want them to be, but ohmyword are they lightyears above what I was making eight years ago.  Phew.

Also in the kiln are a handful of bowls, some bottles, a few hand-built plates.  And these here test thingies.  Coloured slips.  I'll have more on this when I open the kiln.


And - wonder of wonders, without any warning, I decorated a plate one Saturday morning!



No, I really did.  Unbelievable, yes.  All previous attempts at deliberately decorating the surface of any pots has failed miserably.  But here I'm trying it again.  My drawing abilities are ... poopie.  (Hi, I just said, "Poopie.")  But this here just is a test.  If this concept - areas with flashing slip, other areas not, black stain atop either/or - works at all, I'll be employing the services of one Husband Fella.  Husband Fella is absolutely talented with a stack o' pencils, pencil crayons, and markers.  If I can make the process work, I'm certain I can take some of his art and transfer it to pottery.  Fingers crossed.

Fingers very tightly crossed, yes.  Made a few changes to the kiln.  Out to check on it now.  Full report on those changes, and the firing, coming soon.

Thursday, April 24, 2014

A Shed Visit

This week, Peter and a group of his ceramics students from the New Brunswick College of Craft and Design made a trek over this way to visit some potters.  And they stopped to see me, too!

As my pots are just in their infant stages, they primarily asked me questions about my shed.  And I asked gobs of questions of Peter about my kiln.  (He suggested a higher/tighter bag wall and a more substantial target brick.  Okay - this I can do!)  It was a quick-ish visit, really.  But then I tagged along for the rest of their tour.

Three studios and one cafe stop later, I was chock-full of ideas, inspiration, and even a wee bit of frustration (Oh, how I envy the time these students have to spend on their pots!).  And I even got to finally meet Mr. Tim Isaac.



Who was nice enough to take hold of my camera so I could jump in, too:


Thanks (for the 80th time, I know), Peter and ladies!

Time to get to work.

Saturday, April 19, 2014

Big Anthony's Third Firing: Getting Closer!

Well.  Thanks to a well-timed phone call from Peter Thomas, who not only explained what I needed to change to achieve reduction (close the primary air), but why (no matter how many times I've read it before, it only made sense when he spelled it out for me in 15 seconds flat), and most importantly talked me down from my high level of stress that comes when I cannot get the damn thing to reduce ...

It worked!

  • The flame was much happier this time from the burners - blue and strong, with a good sound.
  • I did get the kiln to cone 6 without using a single piece of wood.
  • The firing was quite even, compared to previous efforts (range of soft cone 5 to hard cone 6).
  • I did get some reduction, albeit on one shelf.
  • I did get lovely soda, albeit on the same one shelf.  (Because I didn't clog the sprayer - finally!)

It took 16 hours or so.  (All but one piece had been fired before, so there wasn't the need for slowness at the beginning.)  This really helped, to assure my brain still worked by the end.

Marc Ward has told me it takes between five and eight firings to figure out a gas-fueled kiln.  But I've read elsewhere it takes some folks years.  Having never fired a gas kiln (besides my own two small ones) before this, or even witnessed someone else fire theirs, I'm very, very happy things are starting to look up already, after only three firings.  I credit it solely to an awful lot of help from afar.

So, here's what I need to work on:

  • The burners were maxed out hours before the cones fell.  Things were very, very, very slow at the end.  It's perfectly fine if this is the way it's always going to go, but it just makes me nervous that it won't work if the kiln is more tightly stacked, or it's less windy, or if I stand on one foot too long, etc.
  • The flame came into the kiln hard and fast, hit the bag wall, went straight up.  I had no way of seeing the flame at the top, but further down the kiln I had a hole where I could see that it was now very, very soft and licking, and it had gone over the bag wall, through one shelf, then down, under another shelf, and out the flue.  This one shelf the flame touched is the only one with any reduction, and it received most of the soda, as well.  (I'd like that soft flame to make its way throughout the entire kiln, not just one shelf.)



  • A couple of the pots (all on that one shelf) have some small cracks.
  • Reduction is still a mystery.  I'm attempting a body reduction from 1623°F to 1800°F, and I believe I was not able to achieve it this time.  Although the last few hours of the firing it was in reduction the entire time - and I couldn't make it not reduce.
  • I have to fire with the damper open only half an inch or less.  This just doesn't seem right to me.

And!  Here's what I hope will help answer these questions:
  • Peter.  He's bringing a group of his students to the area next week, to visit a handful of potters.  They're coming here first, and I have high hopes I can bribe him with cookies for some detailed kiln help.
  • Apparently I need target bricks in front of the burners.  And hopefully Peter can explain why!
  • I had very few pots on the kiln.  Partly because I figured it wasn't going to work and didn't want to ruin more pots, partly because I just don't make enough.  But packing it more evenly, and tightly, should help.

In any event, folks.  This here is what the kiln looked like when I opened it up:



This is the top back shelf, the one that saw the least soda/flame/reduction (D in drawing above).

The two creamy white pieces on the right were glaze with Malcolm Davis' shino - this is what this glaze looks like in reduction.

Next to it, the top front shelf, which did receive some soda (C):


Bottom back shelf (B):


The shelf that saw all the action (A):

The two mugs on the left were put into the kiln completely dry on the outside - no slip, glaze.  The three you can see on the right had a couple different slips on them.  Both of these slips, throughout the kiln, actually repelled soda (which was not my goal) and left some colours behind, depending on the clay body and the placement in the kiln.

Some of the better pieces, mostly from that shelf:


Yes, I'm aware the photos above aren't exactly professional.  Neither is my setup.


Although it's handy to have a banjo case hold up your light reflector thingie.  And who doesn't need an accordion in their photo studio, really?

Did a Spring Cleaning of the workshop yesterday, hoping to do the same for the kiln shed today.  Photos coming soon.

Sunday, April 13, 2014

Big Anthony's Second Firing: Day Two

Well!  That second firing didn't go so well, but - again - oh my, did I learn so much.

Basically, it stalled at 1900°F again, and I again used wood to reach temp.  I again screwed up the reduction, and I again screwed up the soda.  But this time I did not fail at cooling!  Yay for me!

After a week of fairly constant research, questions asked online ("Where opinion masquerades as fact," Marc Ward says) and of Mr. Ward, I've come 'round to the following conclusions:
  1. The brick in the flue was a very bad idea. (Here seen from the inside, as I was loading the kiln, and from the outside, looking through the chimney, during firing.)

    Will not be sticking that in there again.
  2. The Venturi layer in the stack was probably a bad idea, too, but there's nothing I can do about that now.
  3. The regulator - which I thought was non-adjustable, needed to be adjusted to allow more pressure to the burners.
  4. My bag wall sucked, and was not even really a bag wall.  It was just one brick high (4.5"), but I've now increased it to three bricks high (13.5") with some spaces throughout.

    Two of my soda ports are now on the wrong side of the bag wall. We'll see how that affects things.
  5. The chimney is, more than likely, not tall enough.  However, I cannot increase the height with more hard bricks - as the slab beneath the kiln/chimney wasn't reinforced and would crack under more weight.  After much searching, I've procured a 14" diameter, ~36" high pipe to set atop.  Husband cut off the bottom and guy wired-it to the chimney.

  6. I was using far, far, far too little water in the sprayer, which fatally clogged it up again.  I believe I've fixed it now, and understand 1. The proper ratio of water to soda; and 2. That I need to keep the solution hot between charges.
  7. I'm also doing my best to keep some space between the shelves, to help the heat circulate evenly.
As I understand, my basic issue is this:  With the tiny bag wall, the flame was coming into the kiln, jumping over the wall, and going directly out the flue - instead of what it should do, which is hit the bag wall, go up to the ceiling, and circulate down around the shelves, then go out the exit flue.  As a result, the kiln wasn't getting hot enough - all the heat was going straight out.  This was causing the stall at 1900°F.  I was firing the kiln with the damper almost completely closed, in an effort to keep the heat inside - and this made it impossible for me make the very slight adjustment then necessary to achieve reduction.

Hopefully now, with the flame coming in stronger and hitting this better (fingers crossed!) bag wall, I'll be able to fire with the damper in a better position (further open).

As it could go All Wrong again, I've decided to just fill him up with the same pots as went through the last firing.  As I can fire it faster, and the pieces are ruined already anyhow, it takes a fair amount of stress about it.

Put a fresh coat of kiln wash on the shelves yesterday.


And even got to work on one of the missing kiln shed walls.


It even has a window!  Pic to follow.

Tonight I'm readying myself mentally to fire tomorrow.  Wish me luck!

Sunday, February 23, 2014

Big Anthony's Second Firing: Day One

Friday:  Make new interior glaze sprayer thingie (as seen in previous post).  Add slip and glaze to pots.  Mix a new batch of wadding.  Make a couple hundred little balls of wadding.



Try to stay in your sticky seat if you can, while listening to an incredible playlist of, well, incredible music.



Arrange everything all perfect-like on the taped-out shelf templates.



Saturday:  Place everything, on wads, on shelves (or on other pots, on shelves).  Including a couple little saggars filled with various goodies.  This one copper wire, another a piece of charcoal, others various oxides.



The cup with the black line, front left, ended up lying on its side, atop the box.  Wadding in between box and cup.  The idea is the copper will burn in the kiln, and whatever flies up from it will land squarely on the side of that cup.  This is the idea.  The idea.



This here is a bisqued platter I made ten years ago or so, back in Illinois.  When Glen picked up Strega Nona last fall, he took this home with him.  He put it into a shallow container filled with ... um, something that rusted?  I can't remember now!  But, through osmosis, it drew the iron up (well, in this photo it would be to the right-ish) and deposited various lines all through the pot.  Along the way it also grew some mold, but nevermind that part.  We're both excited to see how it comes out of the soda kiln.



While I played in the shed, Super Husband put two new soda/wood holes in the kiln (pic in next post).  Then, because I like to do everything the difficult way (or ask others to do so), he kindly carried out the shelves - fully loaded, pots teetering on their little wads - and placed them on the wadded posts.

Then it was time to roll.  Built a quick fire in the chimney to start a draft.



Remembered at the last second to put a brick in the flue (a recommendation from the folks at Ceramic Arts Daily forums, with hopes that it will help me get past 1900°, where it stalled last time before I started adding wood).



Three-year-old stoker.



So.  Planned changes from first to second firing:
- Fire to 1100°F (through quartz conversion), slowly, on Day 1, close it up and go to bed; SLEEP; Fire to temp, quickly, on Day 2
- Put two new holes in middle of kiln, for soda/wood
- Place brick in exit flue (see above)
- Cover extra hole in damper (slot for damper is about 1/2" higher than the damper itself - just need to set brick on top of damper / in front of this hole)
- More soda
- Do not attempt to down-fire.  Just close all ports and damper as tightly as possible.

Saturday we slowly fired to 1100°F, just as planned.  Buttoned it up tightly and really did sleep (as much as you can with a three-year-old who wakes up screaming in the night because she needs to pee, then spends an hour or so lying next to you, pulling your hair, while she tries to get back to sleep).

Sunday ... Well.  That report will be here soon.

Thursday, February 20, 2014

Gearing Up

Pint o' grog, anyone?

  A friend made a straight rib, angled just so, to help me make pints.  None of these are exactly what I'm shooting for, but each one gets closer.

My six-year-old took this photo.  Glazing today!  One piece broke thus far.  Ah, the joys of raw glazing.


Now that I understand exterior slip must be applied before interior liner glaze, I had to come up with another method for applying said liner glaze.  (Because I am incapable of pouring glaze into the piece and pouring it out without dripping onto the exterior - and with the slip already there, now I can't wipe off those drips.)


Ever-Helpful Husband, upon hearing my needs and wants, declared he had a submersible pump I could use.  He even dug long enough to find the fancy valve thingie for the top.  We are hoarders, hear us roar.

Worked great in the sink with water and a trashed mug.  Took it out to the shed, and - Ayup!  It's a winner!  Works perfectly.

Phew.  (Reminds me of my way-fancy "plywood + 2x4s + junked exhaust fan" garage spray booth back in Illinois.  I've been high-society for decades, folks.)

I'd like to cut a couple/few more soda ports into the kiln before firing, but otherwise I think we're ready.  Hoping to slowly get through 1060°F on Saturday, shut it up tight for the night (and go to sleep!), then fire to temp in about 12 hours on Sunday.  Cross your fingers!