Jump to content


Kristin_Gail

Member Since 13 Nov 2012
Offline Last Active Yesterday, 09:25 AM
-----

Topics I've Started

Substitute For Epk In Soda Wadding

16 May 2014 - 11:17 AM

Accidentally used the all but a tiny bit of my EPK today, mixing up a bucket of glaze.  But I really need to mix wadding tomorrow!  I use 50% EPK and 50% Alumina Hydrate.

 

I have Glomax - can I substitute this for all of the EPK?  There's an article here at Ceramic Arts Daily saying I can substitute half of the EPK with Glomax.  Wondering if I could substitute all of it?


Real-Time Kiln Advice (Kiln Curently Firing)

15 April 2014 - 01:07 PM

So. I'm finally firing my kiln again (see last firing's questions here: http://community.cer...taller-chimney/).

This time, I adjusted the regulator to fully open; built the bagwall up to 13.5" high (with spacing in wall), from a previous 4.5" high; and put a 36" metal extension on the chimney.

The burners are far, far happier - they're burning blue instead of orange.

But I still have to fire with the damper almost completely closed if I want the temp to rise at all. It's a 9 x 9 hole, and there's only a 1 x 9 section open right now. Anything more than that, and the temp drops rapidly.

I'm re-firing all the pieces from last time, so figured I could go faster than usual. Averaging about 250/hr or so. I slowly raised the gauges (measured in water columns) every so often - every 2-3 hours.

I'm at hour 7 of the firing, and the dials on the burners are almost maxed out (4.5 of 5.8). Temp is just below 1600°F. Rising okay for now - about 200°/hr.

I'm concerned that, in a few minutes, I will again - for the third time - fail at reduction. With the damper closed down so tightly, there isn't much wiggle room between neutral and smoke. I have such a difficult time finding that "4" flame from the spy holes" spot.

In addition, with the dials being so close to fully open, I will again be stalling at 1900° (for the third time).

Honestly. What in thee heck am I doing wrong?

John B. mentioned that a novice error is to turn up burners when really what you need to do is turn them down. I've tried this. I've tried moving the damper to all sorts of positions, gauges up and down, etc. The only thing that makes temp rise is closing the damper way down and, oddly, taking OUT the kiln shelf I have covering the gap above the damper. (Does this make sense? The damper is thinner than the damper slot, so someone here told me to cover the 3/4" high gap with something. When I cover it, the temp drops.)

Geesh. Getting close to reduction temp now ...

Troubleshooting This Converted Kiln O' Mine: Taller Chimney?

24 February 2014 - 02:02 PM

I fired my kiln, Big Anthony, for the second time this weekend.  The first firing taught me an awful lot - and you folks, more, here.  (Well, many other threads, but that was the latest.)  This time was pretty well a failure.  I messed up the reduction (again), I screwed up the soda (again - worse than last time).  But I did succeed in not crash-cooling!  Woo for me!

 

I'm certain all the problems I'm having are 1. My fault and 2. Obvious issues.  The sort that, when identified, will make you throw your hands in the air and say, "MY GAWD!  How stupid can she be?  Yes, you have to close the lid!" or something equally as neophyte.  If I could have someone knowledgeable on-site, for maybe an hour or two of the firing, I'm certain all questions would be answered.  However, not having that option, I'm here to bug the heck out of you guys instead.

 

The issues:

  • With my former little kiln, I could put it into reduction by moving the damper.  With just an 1/8" move, I could make it smoke, or shoot out a 4" flame, or nothing.  I labelled these options "bad, reduction, and neutral."
    It is not so easy with this bigger kiln.  Now I either get 1. Gobs of black smoke (damper pretty well closed); 2. Nothing (damper open 1"); or 3. Rapidly decreasing temps (damper open more than 1").  I can't find that "short flame shooting out" place.  This all assumes I'm firing with gas only.
     
  • The damper has to be closed down to only 1" open in order to increase temps.  Open more than that, it won't go up.
     
  • It stalls out at 1900°F.  I use wood after this, and when I do, I don't do it right.  Wood creates massive fires coming out of peeps when opened, accompanied by gobs of black smoke.  Each time I add wood (about every 10 minutes at 1900°, closer together at the end) I open the damper up to 3", to try to avoid this effect, while watching the temp drop rapidly.  Over a 3-4 minute period, I slowly close the damper back down to 1" as the smoke lessens.  Once it gets back to 1", the temp rises again.
     
  • Many pieces are cracked - either where I attached handles, or where there was a paper-thin crevice (I have a nick on a rib I use on the outside of pots - it leaves the tiniest groove.  This groove grows in the kiln and in some cases cracks.), or in the foot.
     
  • I don't think I'm using the burners properly.  They just don't sound right.  They sound loud and dirty and orange.  I've messed an awful lot with the primary air thingies, and it doesn't do much.  (I took a video; I'll see if I can find it.)
    It's a low-pressure system.  The dials go up to 10 PSI, but when both are burning, they max out at 5 PSI.  They're MR100s, running together on two 100-lb tanks.  The wind was strong this weekend, and when it really gusted, it made brief back-burning noises.
     
  • It fires very uneven - at least two cones difference from top shelf to bottom shelf, probably much more.  There are only two shelves, and I put a third, empty, shelf atop all of it, in hopes of keeping the fiber roof from falling on the pots.

Okay.  So here are the facts about the kiln and the firing:

 

  • I followed two of your recommendations this time.  1. I put a half brick in the flue and 2. I covered the hole above the damper with two pieces of kiln shelf:

    21.jpg

    20.jpg

    18.jpg
     
  • I'm still single-firing, but to save me from a tiring 24-hour firing, and upon the recommendation of Marc Ward, I fired slowly (9 hours) through 1100°F the first day, shut it up tight and slept.  Then, on Day 2, I fired quickly (8 hours) to Cone 6 (it was 200°F when I began on Day 2).
     
  • When peering into the kiln, I can see the the majority of the flames are going right under the bottom shelf, directly out the flue.  The bag wall is 5" high, but the bottom shelf is a bit higher.  I'd say about 1/4 or less of the flames go above the first shelf, and none of them reach the second shelf.  Hopefully you can see what I mean in this photo about the height of bag wall vs. shelf.  I figure I need to make that higher than the bottom of the first shelf?

    22.jpg

[Split into two posts to accommodate all the photos.]


Soda Wadding Recipe Sources?

21 February 2014 - 04:41 PM

After a series of exhaustive Google searches, I've decided everyone holds their wadding recipes very, very close and dear.  Is this true?  I've found gobs of recipes for wood-kiln wadding, but little to none for soda firings.

 

I used Gail Nichols (I think?) Alumina Hydrate 80 / EPK 20 + a dab of plain white flour in the past, but what an icky white spot it leaves.  Oh, to find some incredible flashing à la Simon Levin and other fine wood firers!

 

I'm using a 50/50 ratio (+ a hint of flour) this time, and will liberally roll the wads in different oxides, as an experiment.  Maybe one of them will flash?  We'll see.  But otherwise, I see no references - anywhere! - to even a starting point for experimentation.  Except that using sand and/or sawdust, great for wood-only, would only leave me with fused pots in a soda kiln.

 

If anyone has any references, I'm all ears!


First Firing Of This Here Electric-To-Propane/wood/soda Converted Kiln

23 January 2014 - 01:35 PM

Oh my, all the help I received here in the planning, purchasing, moving, building, firing of this thing!  Am I ever thankful for this place.

 

Thought I'd share just a bit here.  Details are on my blathering blog.

 

This is Big Anthony.  I think his chimney is too big.  But he works just fine.

 

69.jpg

 

I'm single-firing, and the process took about 21 hours, freezing cold to Cone Six.

 

He stalled at about 1950°F, and I fired the rest of the way with the addition of wood - which I'd planned to do, anyhow, for fun.  Just didn't realize I'd have to do it.

 

Learning is a process, right?  I completely screwed up the reduction I was hoping for; I only had four soda ports, located between the firebox and the shelves, and didn't get all of my soda introduced (near the end, the metal wand from the garden sprayer shot out of the sprayer, laying squarely in the firebox); and I accidentally crash-cooled it.  But I still got some great teaching results, considering this was the first time I'd ever fired any non-electric kiln beyond a couple test propane/soda kilns.

 

01.jpg

 

21.jpg

 

12.jpg

 

I learned a lot - ohmyword, so much - from this firing.  So much about firing this kiln, and firing kilns in general, about slips and glazes, placement of pots in the kiln, what my brain can and cannot compute on no sleep ...

 

In any event, it worked!  I'm forever thankful for all the help I received here.  It worked!