[Clayart] Flame movers
robert hackert via Clayart
clayart at lists.clayartworld.com
Wed Feb 18 12:47:15 EST 2015
When I lived up in NJ I had purchased the Olympic raku/cone 10 kiln where you crank the body up to load and unload.
It took some time to get it right. I agree with all your observations. Their thermocouple was terrible, I removed it because it kept shutting the Baso valve down always in the middle of a firing. After that no problems. Half shelves were the answer. 1" off the floor, I also used flame splitters over the inputs. And, a full shelf did hold and even out the heat distribution. My cone packs agreed
Just my $.02.
Sent from my iPhone
> On Feb 18, 2015, at 12:30, James Miner via Clayart <clayart at lists.clayartworld.com> wrote:
> 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.
> Good luck.
> 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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