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Pics Of Electric To Propane / Soda Conversion

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Here's a dreaded copy-and-paste from my blog.  Wanted to make sure I shared it here, too.  I've had an awful lot of help from folks here.  Maybe someone someday can glean something helpful from this story.




In the Summer of 2012, I brought home this little Paragon electric kiln (from the next province over - and oh, what an adventure this trip was!) and parked it in the driveway, covered in a bright blue tarp, for the winter.  My neighbours were pleased, I'm sure.


This Spring, we moved it to the back yard.  Where we covered it in a bright blue tarp.  The opposite-side neighbours were even more pleased.  I'm sure.




I named her Strega Nona.


We immediately set to work, converting her to burn propane (and eventually play with soda).




We initially used a large bit for the holes - burner port and the first soda port - but that didn't go so well.  At all.  So we switched to the grinder for the metal, then a smaller bit for the brick portion of the smaller soda ports.







She was a mess afterward.



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But I vacuumed her out and filled 'er up.  Full of cylinders.  And a few mugs, because I just couldn't leave well enough alone.









And let 'er rip.




Having only fired a smaller propane kiln a handful of times, I think it's safe to say I had no idear what I was doing.  I called Marc Ward once to ask him about it, he said it sounded like it was doing fine.  But I really didn't like the sounds coming from the burner.  So I called him back, brought the phone out there with me, and described it in more detail.  "Turn it off!" he calmly told me with utmost certainty.  Back-burning.  Oh!  Okay.


I let it sit for a week or two, while I researched further this whole concept of Venturi burners.  And visited a pottery instructor at the local craft college, who not only encouraged me but gave me a semester's worth of firing information in a single one-hour sitting.


I tried again.




It worked this time.  I was pleased.  Very, very pleased.  I reached temp!  Holy crap!  (There was some concern from Marc Ward that perhaps my little burner wasn't going to do it.  But it did.)



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I had filled the kiln with primarily cylinders, every single one coated with Malcolm's Shino.  Did you know shinos have a shelf-life?  And that shelf-life is far shorter than 8 years?  Ah well.  Now I know.  I did know the probability of failure was high, so didn't expect much.  I was just thankful at least one shelf reached Cone 6 and only two pieces blew up.




And both of those pieces were basically in the path of the flame.




Which, I think you can see from the pic above and just below here, came into this little tunnel made out of bricks with a broken kiln shelf atop, then hit this target brick and splashed upwards.




I believe it was about a Cone 4 in the middle, and who knows what on the very top.  The very top shelf was an empty full round, just hoping to keep the heat down.  On top of this full shelf, just an inch below the exit flue, I also placed a little broken kiln shelf.  Another attempt at slowing down the flame.  My analog pyrometer either wasn't working or was just behaving the way an analog pyrometer should, and I had no idea what was going on in there.  At the end I was firing way too fast, and wasn't able to catch it in time to slow it down and even out the heat.


I bought a digital pyrometer.  And asked three trillion questions of oh-so-patient people.  Convinced I was ready to really go for it, I coated the entirety of the thing with EPK and Alumina Hydrate (can't remember the ratio right now).




Then started loading it back up.  A process that took a full four hours.  This is a seven-cubic-foot kiln.  Of which I'm stacking about, oh, 4 cubic feet.



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So I had three soda ports, two spy holes, and a flame path to work around.  Constantly trying to make big holes for the heat to work itself up - but slowly - instead of getting stuck at the bottom.


I placed broken kiln shelves under the soda ports to protect the kiln floor.  And three shelf supports were just inside each of the soda ports for me to set the soda mixture atop (details in a few pics).






By the time I got to the top full-round shelf, I was cantilevering the damn thing off three different-height shelves + the floor.  All on wads, all teetering and tottering and holy hell I was convinced the entire thing was going to implode.




It sat for a week while I waited for the planets to align.  Then they did.  So I fired it again.  If only I remembered how much soda I introduced, I'd sure love to tell you.  But I do know I used Gail Nichols' chunk method.  I shoved each chunk in riding on a little sled of tree bark.



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This one has [Alberta Slip Clay + water, stick-blended into a slip] brushed on while still on the wheel.  Clear Liner Glaze (from Mastering Cone 6 Glazes) liner, poured in at bone dry.


(Wait.  This is the part where I defend myself by stating I really do know how to take proper photos of pottery.  And I promise to prove it - at a later date.)




And this one was dipped into the same slip (so it's much thicker) when bone dry, with Bone glaze (also from MCSG) poured in at bone dry.  This one has that tiny bit of soda on the right - I'd love to see how this slip looks thick like this but with lots of soda.




Oh hell, I don't know which slip this is.  It's out in the shed, in my notes.  But it did do something!  Only where thin, though.  Also brushed on when the cylinder was still wet.




And this one was just dry, but with the liner glaze.




If you were next to a port, you got hit.  Otherwise ... Not so much.





I'm not too sure on the actual cone I reached in this firing, because one set was too close to the flame and the other was too high to bend.  But it did seem more even than the first.  I still have no idear what I'm doing with regards to reducing, so no clue on whether that was semi-even or not ...


Because I'm fairly insane, what I took away from this firing is:  I need a different kiln.  I want no part of this updraft system.  I was a crossdraft, damn it!  A want a single firebox!  Big, so I can throw in lots of wood!  And I want it now!


So I spent the next two months obsessing over such an animal.  Then last month I brought one home.  I'm hoping to move into its permanent home tomorrow ...

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