Valerie Hawkins on wed 11 jul 01
I have the opportunity to buy a used electric kiln. It's older, but is
firing well. I was looking at this as potentially an opportunity to make
electric/gas hybrid kiln or use this kiln for reduction firings in some
other manner. This is something I've been wanting to do, but have been
unwilling to risk damaging my 6 month old electric kiln.
Has anyone done this? I read an article on building an electric/gas hybrid
in the winter 2001 issue of 'Pottery Making Illustrated. This article
specifically said not to use an 'old beater' kiln. What constitutes an 'old
beater'?
Any input would be greatly appreciated!
Daniel Dermer on thu 12 jul 01
I went through this conversion a few months ago, and
have logged 10 firings to c10 so far, all using one
25lb tank of propane. Probably need to refill that
soon.
Mel's directions were great. I found a few tasks to
be more challenging than presented, perhaps because of
my own lack of experience:
1. Changing the kiln elements. My older Duncan kiln
was in reasonably good condition, with few brick
chips/cracks, etc. The process of removing the old
elements and installing new ones coated with ITC213
was difficult! The new elements were not that
flexible, did not sit well in the grooves, and broke a
few channels right off because of tension in the
coils. Next time I will do better, but this task
alone of installing new elements took a whole
afternoon, with lots of frustation over brick damage.
On balance, the few damaged grooves don't seem to
affect firings.
2. Spraying the ITC100 on the inside of the kiln.
Because of the 'heaviness' of the ITC, I could not get
it to suspend well enough to spray evenly. Finally, I
just gave up and painted the inside with a paintbrush,
allowing me to stir the ITC mixture every time I
dipped my brush.
3. Buying/Ordering all the materials was expensive
since I didn't have much of the equipment described in
Mel's directions, except for the older kiln. Here is
a list of items I ended up buying:
- Drill bit, 1.5", for hole in top/bottom (<$10)
- 8 new coils from Euclids, plus new connectors ($115)
- ITC 213, 100, 296, 1 pint each (~$100 from ClayArt
Center Online)
- Air compressor from Home Depot (~$100)
- EZ Sprayer Spray Gun (~$20)
- Bunsen Burner from Frey Scientific (~$20)
- Burner regulator assembly + hose from Ward (~$140)
- 25lb Propane tank, filled ($45) from OSH
- Pyrometer, analog (~$90)
- Kaowool ($10)
- Cones (c10 bars for sitter, c9,10,11 witness cones)
Overall, I think the process was well worth it. I'm
having a great time firing to c10 in reduction. I
haven't done a single c6 oxidation firing since!
-Dan
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