Carol Tripp on fri 12 may 06
Hi,
Had a small brain wave regarding using paint brushes to work glazes through
a sieve. My trusty stiff bristle paint brush finally broke apart and I
couldn't find another stiff one in the only paint brush store around; Ace,
yes there is Ace in Dubai but it's full of camping and gardening gear with
very very little hardware or anything else useful. I do so love a good
hardware store... I digress. I bought a replacement brush but it was too
bendy. Ah - ha - I grabbed the scissors and cut that brush off short and it
works better than my old one ever did.
I had one of those "chrismas morning" type kiln openings recently. All the
pots were refires with "what the hell" glaze combinations on them and a new
fire down schedule to boot. Wow. I opened the kiln to find a load of what
my husband calls ' Bobby Dazzlers'; runs and drips containing crystals 1/2
cm across (this wasn't a crystal fire down), melts that had the look of a
lead-based glaze without the lead, and one that had green lichen all over
it. But best of all, the new fire down schedule cured all the pinholes in
absolutely everything.
I cannot give the exact temps for the firedown because my TC's have big
offsets programmed in. (My top temp is 1175C for ^6 tip touching so you see
what I mean...) But, I can say that I reach top temp, soak until ^6 falls,
fire down at 25C/hour to 50C below top temp, then let the temp fall to 1037C
and then slow down again to 50C/hour until 760C and done. It's the really
slow cool down near the top that gives the glazes time to heal over.
Best regards,
Carol
Dubai
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Hank Murrow on fri 12 may 06
On May 12, 2006, at 10:37 AM, Carol Tripp wrote:
>
> I had one of those "chrismas morning" type kiln openings recently.
> All the
> pots were refires with "what the hell" glaze combinations on them and
> a new
> fire down schedule to boot. Wow. I opened the kiln to find a load of
> what
> my husband calls ' Bobby Dazzlers'; runs and drips containing crystals
> 1/2
> cm across (this wasn't a crystal fire down), melts that had the look
> of a
> lead-based glaze without the lead, and one that had green lichen all
> over
> it. But best of all, the new fire down schedule cured all the
> pinholes in
> absolutely everything.
Dear Carol;
We told you! Almost gives the impression that they were fired in a much
bigger kiln. That is what your fire-down schedule can do for the
glazes.
Cheers, Hank Murrow
www.murrow.biz/hank
Carol Tripp on sat 13 may 06
Bert wrote, in part:
. I slow cool as you describe and using
>John & Ron's firing schedule. Still have had issues with pinholes. Would
>you mind describing in more detail your "top temp, soak until ^6 falls"?
>Do you let cone 6 touch before you start your fire down? About how long
>is your soak? Any details would be appreciated.
Hi Bert,
I have never been able to leave the computer controller alone to just do
it's thing. I have to be there for each firing to check it and guide what
happens. The strength of the current in Dubai is totally random and this
affects the firing each time. So, I give myself a margin by programming in
a top temp which is really a bit below what is needed to make ^6 fall. Then
I program in an hour for the soak; though I have never needed the whole
hour, so far. (And when the elements start to fail, sometimes the kiln is
so slow that the programmed soak never starts. I just go by the look of the
cones and figure it's soaked enough.) I keep good notes about each firing;
time elasped, the reading for each of the three TC's and what the cones look
like on the base and middle shelf. With this new slow fire down at the top,
I don't let ^6 touch the shelf. I've discovered that when it gets to 2pm or
so, I figure that in 30 minutes I will ramp the program forward and go to
fire down. When I open the kiln the next day, ^6 is tip touching.
Is this clear at all? I think the main thing is to keep good notes on what
you saw and did during the firing and what the cones turned out to be
afterwards and how the glazes looked. Try to replicate the good results and
avoid repeating the failures.
This 25C/hour fall for two hours from the top is my latest thing. I used to
just soak "to taste" (^6 down) and then let the kiln fall to either 1050C or
1037C depending on the glazes I was firing and then firing down slowly using
several different schedules. Then someone on Clayart mentioned giving time
for glazes to heal at just below top temp and I tried 25C/hour for one hour.
That wasn't enough. This slow part has to last for two hours to cure the
pinholes. (I was getting lots and lots of them due to particular glazes
I've been using.)
Serendipity plays a leading roll in pottery. Notes help to repeat it.
Best regards,
Carol
Dubai
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