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gas kiln firing

updated fri 7 nov 97

 

Tschorn on sun 2 nov 97

I just finished building a propane gas fired flat top kiln using IFB
- its a real beauty - (thanks to Steve Branfman, Mel Jacobson, &
Robert Piepenburg). The inside dimensions are 18"w x 18"d x 22"h. The
burner port is 4.5 inches square and I have 2 flues that measure 3" x
4.5". I'm using a weed burner rated to 500,000 btu and 20lb tanks.
This morning I fired it for 4 hours and it never really heated up. A
couple of the bricks near the port did get red and I used a 08 cone.
I have the valve on the tank opened all the way up and I use the
valve on the burner to adjust the output. I tried decreasing the size
of the flues, moving the burner tip closer and farther away. One
thing however, the burner is LOUD. Maybe I'm not used to the sound,
so possibly I don't have enough gas going through it (I am a bit
intimidated by it). Should I open the valve all the up? Should I get
a 30psi gauge? - and if I do, should I put the gauge on the tank or
next to the valve on the burner? Or am I overlooking something else
entirely?

Any help would be greatly appreciated. TIA

JR from Horsham PA
tschorn@icdc.com

Talbott on mon 3 nov 97

Your kiln has a 4.128 cubic feet interior volume... With that small volume
500,000 btu/hr burner is more than adequate... I fire a 50 cubic feet gas
kiln to cone 10 with two burners each rated at 500,000 btu/hr in approx. 16
hrs time in reduction going slow in the beginning. 3 psi of burner
pressure max should be more than enough... Sounds like you are blowing heat
energy right through the kiln. What are you using for IFB's... the IFB's
job is to absorb energy and insulate so the those temps can be reached...
Marshall

>----------------------------Original message----------------------------
>I just finished building a propane gas fired flat top kiln using IFB
>- its a real beauty - (thanks to Steve Branfman, Mel Jacobson, &
>Robert Piepenburg). The inside dimensions are 18"w x 18"d x 22"h. The
>burner port is 4.5 inches square and I have 2 flues that measure 3" x
>4.5". I'm using a weed burner rated to 500,000 btu and 20lb tanks.
>This morning I fired it for 4 hours and it never really heated up. A
>couple of the bricks near the port did get red and I used a 08 cone.
>I have the valve on the tank opened all the way up and I use the
>valve on the burner to adjust the output. I tried decreasing the size
>of the flues, moving the burner tip closer and farther away. One
>thing however, the burner is LOUD. Maybe I'm not used to the sound,
>so possibly I don't have enough gas going through it (I am a bit
>intimidated by it). Should I open the valve all the up? Should I get
>a 30psi gauge? - and if I do, should I put the gauge on the tank or
>next to the valve on the burner? Or am I overlooking something else
>entirely?
>
>Any help would be greatly appreciated. TIA
>
>JR from Horsham PA
>tschorn@icdc.com

2nd ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer 1998)
Details will be forth coming!!!
http://fmc.utm.edu/~dmcbeth/cag/naples.htm

Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box 4116,
Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call first)
Clayarters' Live Chat Room, Fri & Sat Nites at 10 PM EDT & Sun at 1 PM EDT
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Talbott on mon 3 nov 97

You will most likely need a 100 gal propane tank or better yet a 500 gal
tank to prevent "freeze up" on your propane supply... Marshall

-------------------original message-------------------
I just finished building a propane gas fired flat top kiln using IFB
- its a real beauty - (thanks to Steve Branfman, Mel Jacobson, &
Robert Piepenburg). The inside dimensions are 18"w x 18"d x 22"h. The
burner port is 4.5 inches square and I have 2 flues that measure 3" x
4.5". I'm using a weed burner rated to 500,000 btu and 20lb tanks.
This morning I fired it for 4 hours and it never really heated up. A
couple of the bricks near the port did get red and I used a 08 cone.
I have the valve on the tank opened all the way up and I use the
valve on the burner to adjust the output. I tried decreasing the size
of the flues, moving the burner tip closer and farther away. One
thing however, the burner is LOUD. Maybe I'm not used to the sound,
so possibly I don't have enough gas going through it (I am a bit
intimidated by it). Should I open the valve all the up? Should I get
a 30psi gauge? - and if I do, should I put the gauge on the tank or
next to the valve on the burner? Or am I overlooking something else
entirely?

Any help would be greatly appreciated. TIA

JR from Horsham PA
tschorn@icdc.com

101 CLAYART MUGS... A TRAVELING EXHIBIT
2ND ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer 1998)
E-MAIL ME FOR AN APPLICATION
http://fmc.utm.edu/~dmcbeth/cag/naples.htm

Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box 4116,
Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call first)
Clayarters' Live Chat Room, Fri & Sat Nites at 10 PM EDT & Sun at 1 PM EDT
http://webchat12.wbs.net/webchat3.so?Room=PRIVATE_Clayarters
---------------------------------------------------------------------

Pat Clogston on thu 6 nov 97

I'm a relatively new potter, doing raku, and lurking on Clayart for some
time now - hoping for a topic where I could contribute something - thanks
for the opportunity!! Here goes....

I fire a kiln like yours (also thanks to Steven Branfman) using a 100 lb.
tank of propane. It will usually fire to about 1850F or approximately ^06
from cold in less than an hour. Here are some problems and solutions from
my experiences:

1. Iron flake has accumulated in the orifice of the burner - unscrew the
orifice, tap the tube to get the loose flake out, blow out the orifice
itself, and reassemble.

2. The burner's air intake is not adjusted properly - try turning the round
hood part of the burner to adjust it so that the flame is burning about in
the middle of the hood - neither at the orifice nor beyond the hood. This
is tough to explain w/o a picture - but Olsen's "The Kiln Book" has a good
discussion with the needed pictures.

3. Not enough air is entering the burner port - pull the burner back at
least 2 inches from the burner port. It also helps to raise the burner on a
brick so that air can circulate all around the hood - be careful to support
the burner to it doesn't roll!

4. Flue size - I think Olsen says that the input burner port and the output
flue sb about the same size. It sounds like your output flues may be too
big - try playing around with them, covering them with an old piece of kiln
shelf. A pyrometer is a big help in seeing what rate of climb your are
getting.

5. Wind - where my kiln is located on the North Shore of Lake Superior, a
good Nor'easter will get my firing done in a hurry - since the wind is
blowing into the burner port, acting like a fan to boost the burner. But
wind from the other direction will blow the draft right back down into the
flue. I've tried various shelters around the flues to prevent the wind from
entering but it can still be difficult to finish a firing.

6. Sound - you will learn to use the sound of the burner as a guide -
listen as you make changes for a good healthy roar!

Hope some of this helps - now that I've got the hang of it, firing my little
kiln is a lot of fun!

Pat
In Minnesota where we're going to do one more raku firing this weekend....