Lois on fri 30 apr 04
HI Paul, when I read this.... I could not remember writing it....but I coul=
d
have. You just described my kiln.
I have a 40 cu ft downdraft, forced air burners in back with target
bricks in trench. =20
My top is always 1-2=90 cooler... with the middle front being the fastest,
but the bottom ends up hottest!
I have keep the shelves staggered.. pack the bottom tight... Front middle
is packed tight...but the back middle and top is packed loose. That has
helped some .....but not solved it.
I have target bricks 1 1/2 bricks high. I tried raising the target
bricks, to hopefully get the heat up, but I raised them to much (1/2 brick=
)
AND over fired the entire kiln that load. (I don=B9t think it was due to th=
e
target bricks, it was me!) I don=B9t know if it helped or not.. Because I ha=
d
such dead lines I went back to the 1 1/2 bricks to get this show done,,
next firing I am going to try raising target bricks 1/4 brick.
The thing that works best for me is to increase the air flow. Lots of
turbulence helps, but for me it makes the temp rise to fast, so I have
to watch it. And be careful not to go terribly fast. I control reduction b=
y
the damper.
Please, please share all the info you get with me. Lets compare notes
sometime.
lois
--=20
Lois Sharpe
On 4/30/04 7:28 PM, "Paul" wrote:
> Hello,
>=20
> I am still having some trouble getting the top of my downdraft 70 cu.ft. =
car
> kiln to reach temperature. Two forced-air burners coming in from the back=
and
> two target bricks in each flame trench, one about 12" tall to try to get =
more
> heat up in the kiln.
Paul on fri 30 apr 04
Hello,
I am still having some trouble getting the top of my downdraft 70 cu.ft. =
car kiln to reach temperature. Two forced-air burners coming in from the =
back and two target bricks in each flame trench, one about 12" tall to =
try to get more heat up in the kiln. The middle section of the kiln can =
be up to 1 =BD cones hotter than the top; if I could just get this =
differential down to a cone or less I would be in good shape. I have =
made some progress by staggering the shelves and leaving more space on =
the top, but I would like to hear from anyone with this type of kiln who =
has had this problem and figured out how to fix it. All my glazes need a =
full cone 10, but if I fire till the top is at this point there are =
always a few pots lower in the kiln that are overfired - cone 11 down =
flat and even beyond. Any suggestions greatly appreciated. Thanks,
Paul B
Falmouth, KY
=20
william schran on sat 1 may 04
Paul wrote:> I am still having some trouble getting the top of my
downdraft 70 cu.ft. car kiln to reach temperature. Two forced-air
burners coming in from the back and two target bricks in each flame
trench, one about 12" tall to try to get more heat up in the kiln.<
Have you tried moving the target brick closer to the flame?
Bill
Ron Roy on sun 2 may 04
Hi Paul,
=46orcing the flame up is one way of getting the top hotter - the other way
is to cut down the draft out the flue.
Bag walls will help force the heat up before it gets pulled down and out.
Just remember - where you need more heat - direct the flame there.
RR
>I am still having some trouble getting the top of my downdraft 70 cu.ft.
>car kiln to reach temperature. Two forced-air burners coming in from the
>back and two target bricks in each flame trench, one about 12" tall to try
>to get more heat up in the kiln. The middle section of the kiln can be up
>to 1 =BD cones hotter than the top; if I could just get this differential
>down to a cone or less I would be in good shape. I have made some progress
>by staggering the shelves and leaving more space on the top, but I would
>like to hear from anyone with this type of kiln who has had this problem
>and figured out how to fix it. All my glazes need a full cone 10, but if I
>fire till the top is at this point there are always a few pots lower in
>the kiln that are overfired - cone 11 down flat and even beyond. Any
>suggestions greatly appreciated. Thanks,
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
=46ax: 613-475-3513=20
Marvpots@AOL.COM on mon 3 may 04
Question for Ron Roy and others:
I have used a copper matte cone 9/10 glaze for some years with consistant
green breaking to red result.
In my most recent firing (gas cone 10) the results were a nice looking
mottled but brown finish on all the pieces glazed with my copper matte with just
an occasional very small spot of the normal green.
The recipe is :
Cornwall stone:----- 46
Whiting:--------------- 34
EPK Kaolin:--------- 20
Copper Carbonate-----4
Tin Oxide-----------------4
This is not a new glaze batch and this batch is probably 6 months or so old.
Any clues?
Thanks for any help.
Marvin Flowerman
marvpots@aol.com
Lee Love on tue 4 may 04
Hey Marv,
Are you using the same claybody? My copper/strontium mat is
sensitive to iron in the clay body.
Also, when it is thin it will loose color.
Good luck!
--
Lee in Mashiko, Japan http://mashiko.org
http://potters.blogspot.com/ Commentary On Pottery
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