Chess Denman on mon 14 dec 98
Kilns.
I have a self built propane kiln. It is 20(ish)cubic foot and has four
burner ports front and back, down draft design. All goes farely well I can
get oxidation and reduction all the way up to 1300 and it takes about two
days to cool down properly. The only fault is that it is jolly expensive on
propane to fire.
I use four cilinders yolked in pairs to a manual change over one pair going
to the front burners and one going to the back burners.
I reckon to get about three firings out of two cilinders. ie for me #17a
firing. I know I am using a fair bit of gas because the cilinders ice up.
Clearly sometimes I use too much last firing as dark fell I saw I had
flames out of the top of the stack.
But it is too late to alter my kiln design now - it is all cemented in to
place with a house brick surround. Could I fire differently for example if I
fired much more slowly (glaze firings take about 8-9hours including a
1hsoak).
More importantly though somehow propane scares me. I plumbed it all in
myself with copper pipe and meticulously spent ages checking and correcting
all the joins which showed any signs of leakage. I still recheck most times
I fire. But I am still scared. WOuld natural gas be safer? If so could I
reuse my burners by changing them (eg by changing the little nib thing out
of which the gas comes. or would I need a new set.)
I am an enthusiastic amateur with no real ambitions to professional status.
I mainly do reduction firings and I only work in stonewear. THe odd piece is
thrown but most is hand built or coiled (cracks, glaze flowing on the
shelves, things bursting in the kiln etc etc all follow from a lack of skill
and knowledge and an incorrigable belief that the laws of physics do not
apply to me)
Is my fear actually wrongly placed and is propane safer?
The kiln is outdoors down the garden cilinders out doors and so forth
getting gas down there will involve trenches and so forth.
Any thoughts?
Kathi LeSueur on tue 15 dec 98
In a message dated 12/14/98 9:17:41 AM, you wrote:
>WOuld natural gas be safer? If so could I
>reuse my burners by changing them (eg by changing the little nib thing out
>of which the gas comes. or would I need a new set.)
Natural gas is safer in the respect that it is lighter than air while propane
is heavier. If you have a leak, the natural gas will tend to dissapate into
the air while the propane will settle. When lighting your burners the propane
could ignite.
But, there are problems with switching over to natural gas which you must
consider. Propane is based on pressure. Natural gas on volume. You will have
have to replace all supply lines to the kiln. Second, the burners will have to
be modified. If they are commercial burners, such as from Ward, they can
probably furnish you with the correct orifice.
If it were I, I would switch over. Propane frankly terrifies me (yes, I
realize that this is an unreasonable fear). Propane can run out. Tanks can
freeze up. With natural gas it is always there. You never have the risk of
running out in the middle of a firing.
Kathi
paul on tue 15 dec 98
Chess,
Natural Gas and Propane are both explosive and need to be handled with care.
Knowledge on this matter will be your best friend. A major issue to
remember is that propane is heavier than air and if there is a leak , the
gas will be around your ankles, natural gas will rise up and is a little
easier to detect. If you do not have any leaks and your burners do not
blow out (retention tips help this) then you should be fine, if burners do
blow out and unburned gas is going into your kiln you should air it out by
opening the door, damper for a couple hrs before continuing on. I would
carry on with the propane if I were in your shoes. The gas is only as safe
as the person using it.
Best Regards - Paul
-----Original Message-----
From: Chess Denman
To: CLAYART@LSV.UKY.EDU
Date: Monday, December 14, 1998 8:50 AM
Subject: propane vs natural gas
>----------------------------Original message----------------------------
>Kilns.
>
>
>I have a self built propane kiln. It is 20(ish)cubic foot and has four
>burner ports front and back, down draft design. All goes farely well I can
>get oxidation and reduction all the way up to 1300 and it takes about two
>days to cool down properly. The only fault is that it is jolly expensive on
>propane to fire.
>
>I use four cilinders yolked in pairs to a manual change over one pair going
>to the front burners and one going to the back burners.
>I reckon to get about three firings out of two cilinders. ie for me #17a
>firing. I know I am using a fair bit of gas because the cilinders ice up.
>Clearly sometimes I use too much last firing as dark fell I saw I had
>flames out of the top of the stack.
>
>But it is too late to alter my kiln design now - it is all cemented in to
>place with a house brick surround. Could I fire differently for example if
I
>fired much more slowly (glaze firings take about 8-9hours including a
>1hsoak).
>
>More importantly though somehow propane scares me. I plumbed it all in
>myself with copper pipe and meticulously spent ages checking and correcting
>all the joins which showed any signs of leakage. I still recheck most times
>I fire. But I am still scared. WOuld natural gas be safer? If so could I
>reuse my burners by changing them (eg by changing the little nib thing out
>of which the gas comes. or would I need a new set.)
>
>I am an enthusiastic amateur with no real ambitions to professional status.
>I mainly do reduction firings and I only work in stonewear. THe odd piece
is
>thrown but most is hand built or coiled (cracks, glaze flowing on the
>shelves, things bursting in the kiln etc etc all follow from a lack of
skill
>and knowledge and an incorrigable belief that the laws of physics do not
>apply to me)
>
>Is my fear actually wrongly placed and is propane safer?
>
>The kiln is outdoors down the garden cilinders out doors and so forth
>getting gas down there will involve trenches and so forth.
>
>Any thoughts?
Pat Porter on tue 15 dec 98
Hi Chess
At Bicentennial Center, we use gas for almost all of our kilns. I know that
htere are people who are on this list from there that know far more than
what I'm about to suggest to you and I hope they correct me if I miss a
point.
Our large kiln for stoneware has severak burners on 2 parallel sides. Each
set has a main shut-off and shut-offs for each burner. It is much larger
than yours, so kind of adjust for that. It is natural gas. And yes, at
night you can see flames from hte stack and peep holes. We have a smaller
raku kiln with 4 burners - natural gas- each one is independently
controlled. And we have a 2 burner raku barrel kiln that has it's burners
joined to a main shut-off, and a small salt fire kiln configured the way the
larger raku kiln is.
Wuth your kiln, You can have your gas company check the joints once or twice
a year for safety, if you don't have the technical knowledge to do it
yourself and feel safe with your findings.
I have not had the experience to fire with propane, but have heated a
trailer in the high mountains with propane. It is very expensive compared
to natural gas! So if all other things are equal, I would rather use
natural gas. Besides it's more convienient. No lugging cannisters to get
refillied or trucks to replace gas - it's all right there. Might be easier
in the long run to lay the trench and hook up to natural gas.
just my 2 cents worth!
Pat Porter
Aurora Colorado
kitties@pcisys.net
-----Original Message-----
From: Chess Denman
To: CLAYART@LSV.UKY.EDU
Date: Monday, December 14, 1998 6:50 AM
Subject: propane vs natural gas
>----------------------------Original message----------------------------
>Kilns.
>
>
>I have a self built propane kiln. It is 20(ish)cubic foot and has four
>burner ports front and back, down draft design. All goes farely well I can
>get oxidation and reduction all the way up to 1300 and it takes about two
>days to cool down properly. The only fault is that it is jolly expensive on
>propane to fire.
>
>I use four cilinders yolked in pairs to a manual change over one pair going
>to the front burners and one going to the back burners.
>I reckon to get about three firings out of two cilinders. ie for me #17a
>firing. I know I am using a fair bit of gas because the cilinders ice up.
>Clearly sometimes I use too much last firing as dark fell I saw I had
>flames out of the top of the stack.
>
>But it is too late to alter my kiln design now - it is all cemented in to
>place with a house brick surround. Could I fire differently for example if
I
>fired much more slowly (glaze firings take about 8-9hours including a
>1hsoak).
>
>More importantly though somehow propane scares me. I plumbed it all in
>myself with copper pipe and meticulously spent ages checking and correcting
>all the joins which showed any signs of leakage. I still recheck most times
>I fire. But I am still scared. WOuld natural gas be safer? If so could I
>reuse my burners by changing them (eg by changing the little nib thing out
>of which the gas comes. or would I need a new set.)
>
>I am an enthusiastic amateur with no real ambitions to professional status.
>I mainly do reduction firings and I only work in stonewear. THe odd piece
is
>thrown but most is hand built or coiled (cracks, glaze flowing on the
>shelves, things bursting in the kiln etc etc all follow from a lack of
skill
>and knowledge and an incorrigable belief that the laws of physics do not
>apply to me)
>
>Is my fear actually wrongly placed and is propane safer?
>
>The kiln is outdoors down the garden cilinders out doors and so forth
>getting gas down there will involve trenches and so forth.
>
>Any thoughts?
>
Clayman on tue 15 dec 98
Chess,
Oh man go to Natural gas! Much easier to control. I prefer forced air
burners. E-Mail Marc Ward at wardburner@aol.com tell him your situation he is a
good guy and we will not and try and sell you something. Although much more
expensive, but in the long run they will pay for themselves!! As far as which
is safer, I feel that natural is safer because of the of air to gas "control"
and you might find your fire time will be decreased. I have a question for
you. What kind of flu control do you have?
Jav Caniff
Clayman@cshore.com
Larry Phillips on tue 15 dec 98
Chess Denman wrote:
>
> Is my fear actually wrongly placed and is propane safer?
Propane is more dangerous if you have low-lying areas for it to collect
in, should you have a leak. Propane is heavier than air, and will 'flow
into' the low spots. Natural gas is lighter than air, and will rise and
dissipate if it leaks. They are about equal in danger when confined to
an enclosed volume.
--
---------------------------------------------------------------
I like deadlines. I especially like the whooshing sound of them
as they go flying by.
http://cr347197-a.surrey1.bc.wave.home.com/larry/
Joseph Herbert on tue 15 dec 98
Chess Denman asks if propane or natural gas is safer.
Humm. Since both are fuels, there is that fire thing to think about. Beyond
that there are some other things:
Propane is heavier than air, natural gas (methane) in not. This is important
because a heavier gas will collect in a low area if there is a leak. This
could lead to an explosion or flash fire from collected leakage. This is an
important thing and there is no denying the physics of it. Heavy things run
down hill and that includes gases. When I heard welders talking about
standing on their heads for a few minutes every week, I found it humorous.
However, if you are exposed to a lot of Argon gas, how does it get out of your
lungs? How good is the mixing down in those tiny spaces. I don't really know
if their head standing is necessary or doing them good, but I no longer find
it humorous.
Natural gas is lighter than air. This means that leaking natural gas will
naturally mix itself with air to form an explosive mixture. If the mixture is
contained, there is a possibility of explosion or flash fire.
Natural gas probably has a wider range of possible ignition percentage. When
the amount present is too small, the mixture won't burn or explode, when the
amount of fuel present is too large, the mixture won't ignite or burn.
Hydrogen has the highest range from about 3% to over 78 percent. On that
basis, I would guess that the heavier molecule had the narrower range.
Propane is a pressurized, liquefied, vaporizing gas that requires heat to
produce vapor. Propane, under the really wrong conditions, can freeze your
flesh and give you frost bite. Worse, if it is your eye that freezes, you are
blinded.
I don't believe that propane is routinely odorized as is natural gas. This
makes leak detection more likely in the case of natural gas.
On balance, I think natural gas is somewhat safer. That is a relative thing
since both fuels can suffocate you or blow up your house if used carelessly.
We live in a hydrocarbon society that accepts the dangers of gasoline rather
freely. Gasoline is really dangerous stuff but we routinely drive 70 miles
per hour with 20 gallons of the stuff right under our butts. Given this fact,
the debate of safety between methane and propane seems, well, less urgent.
My AOL spell checker does not like contractions much and is particularly
affronted by the contraction for do not. It will allow the usage but it must
change your form of the word to its own. This would be OK with me but it
gives DONUT as the first choice so I have to click on the contraction before
going to the replace button. This annoyance has lead to my new expression of
negation - DONUT THINK. If you see a post where I donut think something is
true or possible, it is not the result of an extended stay at Krispy Kream or
Southern Maid, it's lazy mouse. And donut you forget it.
Joseph Herbert
JJHerb@aol.com
Joseph.Herbert@att.net
Caroline and Hedley Saunders on thu 17 dec 98
Have you considered spraying your kiln with ITC products, according to the
people who have used it and written to Clayart (see archives) I believe it
should reduce your propane usage. It is available in the UK from Scarva
Pottery, they have a web site
http://www.scarvapottery.demon.co.uk/
Caroline
Xdelphin@eclipse.co.uk
Remove the X from the address (there to keep spam spiders at bay)
>----------------------------Original message----------------------------
>I have a self built propane kiln. It is 20(ish)cubic foot and has four
>burner ports front and back, down draft design. All goes farely well I can
>get oxidation and reduction all the way up to 1300 and it takes about two
>days to cool down properly. The only fault is that it is jolly expensive on
>propane to fire.
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