Suchman ceramics on mon 15 sep 08
I have a 'baffle shelf' about 1-2" from the flue. There is 2" space between
the shelves and the kiln walls. One source said I needed more air.
-eric
On Mon, Sep 15, 2008 at 8:08 PM, Sherron & Jim Bowen <
jbowen43@prairienetworks.com> wrote:
> You could also place a shelf just under the exit flu that will slow down
> the
> updraft and keep up the temperature on the pots in the middle of the top
> shelf.
> JB
>
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> ----- Original Message -----
> From: "jonathan byler"
> To:
> Sent: Monday, September 15, 2008 2:45 PM
> Subject: Re: kiln stalls @ ^04
>
>
> your exit flue may be too big. we have about 45 sq inches of flue
>> opening on a large gas kiln that has about 600,000 btu's of heat
>> input. That kiln can reach ^10 in 8 hours if you want it to. your
>> burner ports, if they are 5" x 5" each are also too big if that is
>> the case. your burner ports should be not much bigger than the
>> burner head. too much airflow through the kiln prevents the hot
>> gases from being able to give off their heat to the ware, and it all
>> ends up going out the chimney.
>>
>>
>> jon byler
>> 3-D Building Coordinator
>> Art Department
>> Auburn University, AL 36849
>>
>> On Sep 15, 2008, at 11:30 AM, Suchman ceramics wrote:
>>
>> I have built a gas kiln out of an electric kiln carcass. I use 2 ward
>>> burners. I use propane at a psi of 1-1.5 lbs. 9" exit flue,
>>> updraught,
>>> burner ports are 5" square, loading area is approx. 28" dia x 28"
>>> high.
>>> fire box is 9" high.My last firing took 14 hours to reach ^7 at
>>> the bottom
>>> and ^5 at the top. Very slow climb from ^04 on up. I'm thinking this
>>> firing should only be about 8 hours. How and what can I change to get
>>> better performance? Any ideas?
>>> Thanks for any input
>>>
>>> --
>>> -eric-in-o'side-
>>>
>>> pagan by nature
>>>
>>
>>
>>
--
-e-in-o'side-
pagan by nature
Caleb smith on mon 15 sep 08
Hi Eric=2C
I'm no expert=2C but I do have a kiln built partially of old electrics. I=
too have problems at higher temperatures. Although soft bricks are highly=
refractory=2C I think they leak significantly more than a similar wall mad=
e of hard brick due to their porosity and lower thermal inertia. Soft bric=
k "carcases" tend to be extra leaky. For me=2C that equates to a weaker co=
ncentration of heat in my kiln and considerably more cold air sneaking in. =
Sounds like in your case you would benefit from SMALLER BURNER PORTS and M=
ORE INSULATION. Try an outside layer of fiber blanket=2C castable or even =
steel flashing. Maybe a coating of some sort on the interior would also he=
lp (kiln wash=2C ITC=2C refractory mortar...Shino?). Your cheapest fix is =
cutting a few spare soft bricks with a hole saw to fit tightly around your =
burners and fill up the rest of your burner port holes (5" x 5" probably le=
ts in a lot of cold air). Don't put your burners in the new holes=2C but p=
retty close. You probably know all that already. =20
A 9in diameter flue seems totally adequate=2C it doesn't even seem like you=
would open the damper all the way. Who knows=2C maybe you have Natural Ga=
s orifices in your burners or some such. The devil is in the details.
Good luck=2C
Caleb
> Date: Mon=2C 15 Sep 2008 09:30:24 -0700
> From: suchmanart@GMAIL.COM
> Subject: kiln stalls @ ^04
> To: CLAYART@LSV.CERAMICS.ORG
>=20
> I have built a gas kiln out of an electric kiln carcass. I use 2 ward
> burners. I use propane at a psi of 1-1.5 lbs. 9" exit flue=2C updraught=
=2C
> burner ports are 5" square=2C loading area is approx. 28" dia x 28" high.
> fire box is 9" high.My last firing took 14 hours to reach ^7 at the bott=
om
> and ^5 at the top. Very slow climb from ^04 on up. I'm thinking this
> firing should only be about 8 hours. How and what can I change to get
> better performance? Any ideas?
> Thanks for any input
>=20
> --
> -eric-in-o'side-
>=20
> pagan by nature
_________________________________________________________________
See how Windows Mobile brings your life together=97at home=2C work=2C or on=
the go.
http://clk.atdmt.com/MRT/go/msnnkwxp1020093182mrt/direct/01/=
Suchman ceramics on mon 15 sep 08
I have built a gas kiln out of an electric kiln carcass. I use 2 ward
burners. I use propane at a psi of 1-1.5 lbs. 9" exit flue, updraught,
burner ports are 5" square, loading area is approx. 28" dia x 28" high.
fire box is 9" high.My last firing took 14 hours to reach ^7 at the bottom
and ^5 at the top. Very slow climb from ^04 on up. I'm thinking this
firing should only be about 8 hours. How and what can I change to get
better performance? Any ideas?
Thanks for any input
--
-eric-in-o'side-
pagan by nature
jonathan byler on mon 15 sep 08
your exit flue may be too big. we have about 45 sq inches of flue
opening on a large gas kiln that has about 600,000 btu's of heat
input. That kiln can reach ^10 in 8 hours if you want it to. your
burner ports, if they are 5" x 5" each are also too big if that is
the case. your burner ports should be not much bigger than the
burner head. too much airflow through the kiln prevents the hot
gases from being able to give off their heat to the ware, and it all
ends up going out the chimney.
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Sep 15, 2008, at 11:30 AM, Suchman ceramics wrote:
> I have built a gas kiln out of an electric kiln carcass. I use 2 ward
> burners. I use propane at a psi of 1-1.5 lbs. 9" exit flue,
> updraught,
> burner ports are 5" square, loading area is approx. 28" dia x 28"
> high.
> fire box is 9" high.My last firing took 14 hours to reach ^7 at
> the bottom
> and ^5 at the top. Very slow climb from ^04 on up. I'm thinking this
> firing should only be about 8 hours. How and what can I change to get
> better performance? Any ideas?
> Thanks for any input
>
> --
> -eric-in-o'side-
>
> pagan by nature
Sherron & Jim Bowen on mon 15 sep 08
It should be able to reach cone ten in a few hours in fact. How much space
is there between the shelves and the wall of the kiln. If it's too tight
that could be a problem.
I bet your overdriving it. In my similar set up the burners are not
touching the kiln but are about three inches away. Lots of secondary air is
being entrained. Have you fired it in the dark?
JB
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
----- Original Message -----
From: "Suchman ceramics"
To:
Sent: Monday, September 15, 2008 10:30 AM
Subject: kiln stalls @ ^04
>I have built a gas kiln out of an electric kiln carcass. I use 2 ward
> burners. I use propane at a psi of 1-1.5 lbs. 9" exit flue, updraught,
> burner ports are 5" square, loading area is approx. 28" dia x 28" high.
> fire box is 9" high.My last firing took 14 hours to reach ^7 at the bottom
> and ^5 at the top. Very slow climb from ^04 on up. I'm thinking this
> firing should only be about 8 hours. How and what can I change to get
> better performance? Any ideas?
> Thanks for any input
>
> --
> -eric-in-o'side-
>
> pagan by nature
>
>
Sherron & Jim Bowen on mon 15 sep 08
You could also place a shelf just under the exit flu that will slow down the
updraft and keep up the temperature on the pots in the middle of the top
shelf.
JB
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
----- Original Message -----
From: "jonathan byler"
To:
Sent: Monday, September 15, 2008 2:45 PM
Subject: Re: kiln stalls @ ^04
> your exit flue may be too big. we have about 45 sq inches of flue
> opening on a large gas kiln that has about 600,000 btu's of heat
> input. That kiln can reach ^10 in 8 hours if you want it to. your
> burner ports, if they are 5" x 5" each are also too big if that is
> the case. your burner ports should be not much bigger than the
> burner head. too much airflow through the kiln prevents the hot
> gases from being able to give off their heat to the ware, and it all
> ends up going out the chimney.
>
>
> jon byler
> 3-D Building Coordinator
> Art Department
> Auburn University, AL 36849
>
> On Sep 15, 2008, at 11:30 AM, Suchman ceramics wrote:
>
>> I have built a gas kiln out of an electric kiln carcass. I use 2 ward
>> burners. I use propane at a psi of 1-1.5 lbs. 9" exit flue,
>> updraught,
>> burner ports are 5" square, loading area is approx. 28" dia x 28"
>> high.
>> fire box is 9" high.My last firing took 14 hours to reach ^7 at
>> the bottom
>> and ^5 at the top. Very slow climb from ^04 on up. I'm thinking this
>> firing should only be about 8 hours. How and what can I change to get
>> better performance? Any ideas?
>> Thanks for any input
>>
>> --
>> -eric-in-o'side-
>>
>> pagan by nature
>
>
| |
|
