Janet Harper on thu 11 feb 99
Hi Clayart Friends!
I have built an IFB sprung arch downdraft kiln but haven't completed the
chimney yet. Two questions:
1. when I am calculating the height of the chimney and using the formula in
Olsen's book, is the height of the kiln from the ceiling to the floor of the
flue trough or to the main floor of the kiln? This question would make the
difference between a 14 ft vs. 17 ft chimney.
2. The chimney is HFB up to about 3 feet. I want to add a metal pipe to
complete the chimney. I have been quoted what I think is a high price for a
piece of stainless steel pipe. What is a good substitute? This is outside so
there are no concerns about roof combustion. Would triple-wall stove pipe
work? If so, where do I find it? I have checked the local heat/air guys and
they don't know what to use. Do I need the insulating sleeves in the metal
pipe? If so, Where to find them? What kind of heat are we talking about in
the chimney when I'm firing to ^10? My old kiln was HFB with regular brick on
top. Should I go back to that? I understand that a metal stack will draw
better than brick. True? So many questions and not enough answers! Any
help will be appreciated! Clayart is great...I learn and get inspired every
day!
Janet
Louis Katz on fri 12 feb 99
Down here in South Texas we have lots of pipe from the Oil industry in our scrap
yards. We are using some that is between 1/8 and 3/16 inch thick. It will last a
very long time even on our soda kiln. I would go a bit higher with fire brick to
cool the exhaust, maybe four or five feet. It will make your stack last longer.
Louis
Janet Harper wrote:
> ----------------------------Original message----------------------------
> Hi Clayart Friends!
>
> I have built an IFB sprung arch downdraft kiln but haven't completed the
> chimney yet. Two questions:
> 1. when I am calculating the height of the chimney and using the formula in
> Olsen's book, is the height of the kiln from the ceiling to the floor of the
> flue trough or to the main floor of the kiln? This question would make the
> difference between a 14 ft vs. 17 ft chimney.
> 2. The chimney is HFB up to about 3 feet. I want to add a metal pipe to
> complete the chimney. I have been quoted what I think is a high price for a
> piece of stainless steel pipe. What is a good substitute? This is outside so
> there are no concerns about roof combustion. Would triple-wall stove pipe
> work? If so, where do I find it? I have checked the local heat/air guys and
> they don't know what to use. Do I need the insulating sleeves in the metal
> pipe? If so, Where to find them? What kind of heat are we talking about in
> the chimney when I'm firing to ^10? My old kiln was HFB with regular brick on
> top. Should I go back to that? I understand that a metal stack will draw
> better than brick. True? So many questions and not enough answers! Any
> help will be appreciated! Clayart is great...I learn and get inspired every
> day!
> Janet
--
Louis Katz
lkatz@falcon.tamucc.edu
NCECA Director At Large
Texas A&M-CC Division of Visual and Performing Arts Webmaster (512) 994-5987
Visit the NCECA World Ceramics Image Database
Earl Brunner on fri 12 feb 99
the fourteen cubic foot IFB downdraft that I built in the 70's never had a stack
higher than the arch on the kiln, I intended to go higher, and did so briefly
with firebrick chimney liners, but they heat shocked and fell apart and the kiln
fired fine with out so I never replaced them. If you look at most of the
commercially manufactured kilns on the market today, you will see that they do n
have significant stacks. Geil's stacks do not extend any higher than the roofs
his kilns. I remember the formula in Rhodes' Kiln book gave me some gosh awful
stack 18 feet high or something.
Earl Brunner
Jennifer Boyer on sat 13 feb 99
Hi Janet,
Mark Ward gave me a formula for chimney height of 3X interior height of kiln
(from bottom of flue trench to arch) + 1/3 of distance from interior front of
kiln to interior back of chimney.
Janet Harper wrote:
> ----------------------------Original message----------------------------
> Hi Clayart Friends!
>
> I have built an IFB sprung arch downdraft kiln but haven't completed the
> chimney yet. Two questions:
> 1. when I am calculating the height of the chimney and using the formula in
> Olsen's book, is the height of the kiln from the ceiling to the floor of the
> flue trough or to the main floor of the kiln? This question would make the
> difference between a 14 ft vs. 17 ft chimney.
> 2. The chimney is HFB up to about 3 feet. I want to add a metal pipe to
> complete the chimney. I have been quoted what I think is a high price for a
> piece of stainless steel pipe. What is a good substitute? This is outside so
> there are no concerns about roof combustion. Would triple-wall stove pipe
> work? If so, where do I find it? I have checked the local heat/air guys and
> they don't know what to use. Do I need the insulating sleeves in the metal
> pipe? If so, Where to find them? What kind of heat are we talking about in
> the chimney when I'm firing to ^10? My old kiln was HFB with regular brick on
> top. Should I go back to that? I understand that a metal stack will draw
> better than brick. True? So many questions and not enough answers! Any
> help will be appreciated! Clayart is great...I learn and get inspired every
> day!
> Janet
--
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Jennifer Boyer jboyer@plainfield.bypass.com
Thistle Hill Pottery
Vermont USA
http://www.vermontcrafts.com/members/JenniBoy892.html
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
David Hendley on sat 13 feb 99
Here are some answers to your chimney questions. These are my
experiences/opinions; others may not agree.
1-There is no reason to pay a high price for a stainless steel pipe;
plain steel is fine. Go shopping at the scrap metal (junk) yard!
2-Triple-wall stove pipe would last long at all because the
metal is a very thin gauge. The purpose of the triple-wall is so the
pipe will be cool on the outside. It's not made for the high
temperatures of a kiln. We are talking about a lot of heat.
3-A firebrick chimney is just as good and will draw as good as a metal
one *IF* it is well made and the bricks are motared together so
there are no air spaces.
4-You can buy 'riser sleeves' that are kaowool fiber that fit inside
a pipe for insulation and protection of the pipe. You can spray the
sleeves with ITC to make them work better and last longer. Firebrick
Supply in Minnesota is one source, or check with your refractory
supplier.
5-If you continue the firebrick stack up higher, say to 6 or 7 feet, you
could then go to a steel pipe, unprotected, for the top part of the stack.
This should be a heavy pipe, not a thin-walled duct or sheet metal pipe.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
At 07:48 AM 2/11/99 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Clayart Friends!
>
>I have built an IFB sprung arch downdraft kiln but haven't completed the
>chimney yet. Two questions:
> 1. when I am calculating the height of the chimney and using the formula in
>Olsen's book, is the height of the kiln from the ceiling to the floor of the
>flue trough or to the main floor of the kiln? This question would make the
>difference between a 14 ft vs. 17 ft chimney.
> 2. The chimney is HFB up to about 3 feet. I want to add a metal pipe to
>complete the chimney. I have been quoted what I think is a high price for a
>piece of stainless steel pipe. What is a good substitute? This is
outside so
>there are no concerns about roof combustion. Would triple-wall stove pipe
>work? If so, where do I find it? I have checked the local heat/air guys and
>they don't know what to use. Do I need the insulating sleeves in the metal
>pipe? If so, Where to find them? What kind of heat are we talking about in
>the chimney when I'm firing to ^10? My old kiln was HFB with regular
brick on
>top. Should I go back to that? I understand that a metal stack will draw
>better than brick. True? So many questions and not enough answers! Any
>help will be appreciated! Clayart is great...I learn and get inspired every
>day!
> Janet
>
Don & Isao Morrill on sun 14 feb 99
At 15:02 2/13/99 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Janet,
>Mark Ward gave me a formula for chimney height of 3X interior height of kiln
>(from bottom of flue trench to arch) + 1/3 of distance from interior front of
>kiln to interior back of chimney.
>
>Janet Harper wrote:
>
>> ----------------------------Original message----------------------------
>> Hi Clayart Friends!
>>
>> I have built an IFB sprung arch downdraft kiln but haven't completed the
>> chimney yet. Two questions:
>> 1. when I am calculating the height of the chimney and using the
formula in
>> Olsen's book, is the height of the kiln from the ceiling to the floor of
the
>> flue trough or to the main floor of the kiln? This question would make the
>> difference between a 14 ft vs. 17 ft chimney.
>> 2. The chimney is HFB up to about 3 feet. I want to add a metal pipe to
>> complete the chimney. I have been quoted what I think is a high price
for a
>> piece of stainless steel pipe. What is a good substitute? This is
outside so
>> there are no concerns about roof combustion. Would triple-wall stove pipe
>> work? If so, where do I find it? I have checked the local heat/air
guys and
>> they don't know what to use. Do I need the insulating sleeves in the metal
>> pipe? If so, Where to find them? What kind of heat are we talking
about in
>> the chimney when I'm firing to ^10? My old kiln was HFB with regular
brick on
>> top. Should I go back to that? I understand that a metal stack will draw
>> better than brick. True? So many questions and not enough answers! Any
>> help will be appreciated! Clayart is great...I learn and get inspired
every
>> day!
>> Janet
>
>
>--
>~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
>Jennifer Boyer jboyer@plainfield.bypass.com
>Thistle Hill Pottery
>Vermont USA
>http://www.vermontcrafts.com/members/JenniBoy892.html
>~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
>Hi janet, Put your BIg money in brick....Lasts forever and the price
cannot help but increase over the years. As for pipe: S/S is lovely and
very expensive. We used 14" common galvanized culvert tocomplete the 14et
chimney on our 300cubic ft kiln at St. Ignace,New Brunswick in 1985. In
1995 the kiln and chimney were still in use as a spring project for the
N.S.College of Art&Design and the Universite' de Moncton. Culvert is
heavy,cheap and,readily available. While the formula for chimney
measurement is interesting one must assume that the kiln is useing only
natural draft without the addition of any kind of blower. The St.Ignace
kiln was,(or is)an Ana-gama,9meters long set at an angle of app.15o. Width
inside: 1.5m. Height 1.7m. Arch,somewhat less than 6"Rise. We bilt a small
'plenum' chamber just before the entrance to the chimney which helped to
increase gas volocity as well as rducing chimney H. Good luck.
Isao & Don
Dorothy Weber on tue 16 feb 99
On my 54 Cu Ft Minn. Flat Top, I used 3 Feet of HFB to about 3/4 up the back
wall, then put a piece of 12 Ft.galvanized culvert 10 inch diameter. Works
like a charm. You get the culvert from your building supplier. I think if you
have a good location with good cross draft and no obstructions that you will
get plenty of draft. Good Luck.
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