[Clayart] Flame movers
James Miner via Clayart
clayart at lists.clayartworld.com
Wed Feb 18 11:51:37 EST 2015
HI Deb. Like you, I and a lot of other folks have had problems firing the
Olympic Torchbearers for several reasons. Assuming you are using the
previous suggestions you mention, I would add the following. First, use a
top shelf set about an inch below the lid. This helps keep the heat in the
kiln (and minimizes lid debris from falling on the pots, since the lids on
these things seem to crack). Second, I generally put a stilt or piece of
firebrick in the path of each burner on the second and third shelves (but
not the first shelf). This deflects and spreads the flames, and makes a
hot spot that will re-radiate heat back downward to help cold lower
shelves. Third, make a small chimney of IFB around the flue. One brick
high is enough. This helps with drafting issues.
You can also change the location of the hottest part of the flame depending
on stacking and flue position, but that may be too complicated until you
try these first suggestions. I can fire to within one half a cone from top
to bottom this way, even with the flue fully open for oxidizing conditions.
I'm trying to dial it in a little better by changing how BIG of a stilt or
firebrick piece to use to break up the flame, as well trying different as
packing arrangements/flue positions.
On Wed, Feb 18, 2015 at 8:29 AM, Deborah Thuman via Clayart <
clayart at lists.clayartworld.com> wrote:
> Who here uses them? What do yours look like? How successful is your design?
> I've got a gas fired, round Olympic kiln. When I fired the antique gas
> fired Olsen at the local university, I had very little difference in heat
> from top to bottom. Cone packs were nearly identical. I'm not getting that
> in the Olympic. Cold bottom, hot top. I contacted Olympic and was told to
> have a 2" gap in the middle between the bottom shelves and a slightly
> smaller gap for the rest of the levels. Didn't solve the problem. Next, I
> talked to one of the people at NM Clay and was told to cover the hole in
> the top of the kiln even 1/4". Didn't solve the problem. Next, I tried
> another suggested solution, moving the shelves so they partly cover the
> hole where the flame comes through. Didn't solve the problem.
> I was told that the flame is going up the side of the kiln and out the
> hole in the lid. That makes sense. I don't mind partly covering the hole,
> but I don't want too much reduction. I wouldn't mind enough reduction to
> make the glaze colors do really cool things... but.... I'm using porcelain
> and a chocolate colored clay. The chocolate clay is ^5 and that's carved in
> stone. Fire that clay to ^6 and you get land fill. Great for the bottom
> shelf. The porcelain is ^6. But... I'm getting way more than a 1 cone
> difference between top and bottom. What worked best for me with the Olsen
> was ^5 down, ^6 moving, lower the gas and try to hold for 30 minutes (any
> more or any less produced ugly results) and then shut everything down.
> I'm seeing some of my glazes (they are all commercial) getting pinholes.
> This is happening more on the bottom shelf than anywhere else in the kiln.
> I suspect my mugs are telling me I need to get the bottom of the kiln a tad
> All suggestions are welcome. I won't be firing the kiln for a few months.
> It's too cold out to work in my summer studio (looks just like my back
> patio). It's too cold to work in my autumn studio (looks just like a tiny
> corner of the garage). There are some issues with moving into the winter
> studio (looks just like the laundry room) - both issues having four paws,
> lots of fur and the ability to jump up onto darned near everything.
> Deb Thuman
> I can honestly say that I was never affected by the question of the
> success of an undertaking. If I felt it was the right thing to do, I was
> for it regardless of the possible outcome. Golda Meir
> MAILMAN_MIMEDEFANG WRAP
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