[Clayart] Gauges
mel jacobson via Clayart
There seems to be a great deal of giving information based on pressure as seen on gauges for the gas. I do not believe that all gauges read the same numbers. So, from my history and visiting many kilns there is no set markings that indicate exact pressure. Those lines on the gauge front are for you to use and then decide how much you need. When you find a perfect amount of gas, mark the gauge with a sharpy or write it down on the tank. Save the numbers.
I have been to kilns that the owner has been firing the kiln at 12 pounds of pressure he assures me. When you fire the kiln the back pressure from the peep is 20 inches. I turned the gauge down to mark two. There was about 4 inches of back pressure. He fired the kiln for like 7 years with that huge pressure. He said I guy told him 12 pounds. It took him 14 hours to fire and wasted huge amounts of fuel. I fired that kiln in 7 hours, cone ten flat. The pots were perfect. And the pressure gauge on the tank said 63 percent left. We started at 66. I told him “it’s your money, spend it as you want”. I am sure when I left he thought I did hocus/pocus.
Gas is measured in water column. (read about it)
I mark my damper with pencil lines. Line one for early firing to gain heat. Then the mark for light reduction and full reduction. Then a line for closed tight. I fire the entire time with the gauge at two and a half marks. Yesterday I fired my kiln to cone 10 flat in 6 hours and 20 minutes. Lovely oil spot temmoku.
Again, I say, stack your shelves with a stagger. Do not close them up next to each other. If you have a self-argument “should I add these last four pots” say no. Save them for the next firing. Leave room for the heat to travel. Do not build dams. Gas kilns do not need bag walls in most cases.
mel
website: www.melpots.com
WWW.clayartarchives.com
Vince Pitelka via Clayart
There are some photos of the car kiln on the "Railroad Stoneware" page on my website under "Gallery," and on one you can see the whole kiln from the side. You'll see the three little antique gas valves with white porcelain handles on the side below each burner, and the copper tubing leading to the single WCI gauge down at the back end of the kiln.
I did a number of other unconventional things on that kiln just because they seemed like a good idea. PG&E put in a big industrial gas meter and gave me 11 WCI of gas pressure, and I generally glaze-fired that kiln to cone-10 in seven hours. It was the most even, reliable, and easy-firing kiln I have ever used.
- Vince
Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincep...@gmail.com
www.vincepitelka.com
https://chathamartistsguild.org/
Vince Pitelka via Clayart
Just to clarify for those who don't know this, when we refer to low-pressure in gas kilns, we are talking about natural gas or low-pressure LPG. Household natural gas is 7WCI, which is about a quarter pound of pressure. If your kiln is on a separate meter from your household, the gas company is generally willing to boost it up to 11WCI. Low-pressure LPG refers to a setup with a pre-set, non-adjustable regulator, such as is used for household low-pressure LPG systems. High-pressure refers to LPG with an adjustable high-pressure regulator, and is measured in PSI - pounds per square inch. After an overnight preheat at about a half-pound of pressure, my current crossdraft soda kiln stays at 5PSI for the duration of the firing. We have a high-capacity regulator on our 1000-gallon propane tank that is set to 30PSI. A line branches off for the kiln, where there is a high-capacity regulator with a 0-15PSI gauge, while the other branch continues to the house, where there is a preset low-pressure regulator.
All things being relative, the term "high-pressure" is used only because the pressure is very high compared to low-pressure WCI. When I am firing my kiln at 5PSI, the pressure is ten times as high as someone firing a kiln on household natural gas at 7WCI. Industrial burner systems often operate at 10PSI and above, which would be considered very high pressure in gas burner operation.
Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincep...@gmail.com
www.vincepitelka.com
https://chathamartistsguild.org/
-----Original Message-----
From: Clayart <clayart...@lists.clayartforum.com> On Behalf Of mel jacobson via Clayart
Sent: Thursday, November 20, 2025 5:19 PM
To: clay clay <cla...@lists.clayartforum.com>
Cc: mel jacobson <mel...@mail.com>
Subject: [Clayart] Gauges
Vince Pitelka via Clayart
Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincep...@gmail.com
www.vincepitelka.com
https://chathamartistsguild.org/
-----Original Message-----
From: Clayart <clayart...@lists.clayartforum.com> On Behalf Of mel jacobson via Clayart
Sent: Thursday, November 20, 2025 5:19 PM
To: clay clay <cla...@lists.clayartforum.com>
Cc: mel jacobson <mel...@mail.com>
Subject: [Clayart] Gauges
William Schran via Clayart
message this morning, but reading your message covered it.When I first
began teaching I wrote a grant to buy a gas kiln - institution
wouldn't allow building one. I ordered a small downdraft kiln (12cu ft
I think) from California Kiln Company. Fired with propane so got used
to working with gas pressure readings in PSI.When I moved to another
campus I had to build a new ceramics program with me doing most of the
work over weekends. After a few years with increasing enrollment and
only having electric kilns available, I wrote a grant to purchase a
gas kiln and to erect a small building to house the kiln. The grant
was approved but only enough for the kiln, so ordered a brand that was
the least expensive at the time.The college Health & Safety dept.
stopped the purchase stating the gas kiln must have certification from
gas association. Only kiln at the time was the Geil kiln. Price for
the Geil was at least twice what the kiln I ordered was. Fortunately
we had gone through a self study for recertification of the college
and I was head of physical facilities committee. Made close friends
with head of facilities of the college and he learned of the issue
with ordering of the kiln. He told me he would front the funds to
order the Geil kiln AND build the kiln building that would also house
our electric kilns. Said to pay back over time. Well, that next spring
semester he decided to retire and told me if anyone asked, I knew
nothing.... never had to repay.... Any way, the Geil was fueled by
natural gas so I had to learn about using WC - much lower pressure,
but the kiln was so well designed, with burners under the floor, that
I would set the gauge at one setting and simply move the damper in and
out a couple times during the firing.
Bill
William Schran...@twc.com703-505-1617
-----------------------------------------From: "Vince Pitelka via
Clayart"
To: "Clayart international pottery discussion forum"
Cc: vincep...@gmail.com
Sent: Friday November 21 2025 8:31:25AM
Subject: Re: [Clayart] Gauges
- Vince
Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincep...@gmail.com
www.vincepitelka.com
https://chathamartistsguild.org/ [1]
website: www.melpots.com
WWW.clayartarchives.com
Links:
------
[1] https://chathamartistsguild.org/
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Vince Pitelka via Clayart
You were heroic in your efforts to improve your ceramics program with better kilns. It is very discouraging when the relationship between faculty and administration seems adversarial, but it seems that you learned to work the system to best advantage. Your students were very lucky.
- Vince
Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
<mailto:vincep...@gmail.com> vincep...@gmail.com
<http://www.vincepitelka.com/> www.vincepitelka.com
<https://chathamartistsguild.org/> https://chathamartistsguild.org/
From: William Schran <wsc...@twc.com>
Sent: Friday, November 21, 2025 9:19 AM
To: 'Clayart international pottery discussion forum' <cla...@lists.clayartforum.com>
Cc: 'vincep...@gmail.com' <vincep...@gmail.com>
Subject: Re: [Clayart] Gauges
Good and important information Vince. I was planning to write similar message this morning, but reading your message covered it.
When I first began teaching I wrote a grant to buy a gas kiln - institution wouldn't allow building one. I ordered a small downdraft kiln (12cu ft I think) from California Kiln Company. Fired with propane so got used to working with gas pressure readings in PSI.
When I moved to another campus I had to build a new ceramics program with me doing most of the work over weekends. After a few years with increasing enrollment and only having electric kilns available, I wrote a grant to purchase a gas kiln and to erect a small building to house the kiln. The grant was approved but only enough for the kiln, so ordered a brand that was the least expensive at the time.
The college Health & Safety dept. stopped the purchase stating the gas kiln must have certification from gas association. Only kiln at the time was the Geil kiln. Price for the Geil was at least twice what the kiln I ordered was. Fortunately we had gone through a self study for recertification of the college and I was head of physical facilities committee. Made close friends with head of facilities of the college and he learned of the issue with ordering of the kiln. He told me he would front the funds to order the Geil kiln AND build the kiln building that would also house our electric kilns. Said to pay back over time. Well, that next spring semester he decided to retire and told me if anyone asked, I knew nothing.... never had to repay.... Any way, the Geil was fueled by natural gas so I had to learn about using WC - much lower pressure, but the kiln was so well designed, with burners under the floor, that I would set the gauge at one setting and simply move the damper in and out a couple times during the firing.
Bill
William Schran
wsc...@twc.com <mailto:wsc...@twc.com>
-----------------------------------------
From: "Vince Pitelka via Clayart"
To: "Clayart international pottery discussion forum"
Cc: vincep...@gmail.com <mailto:vincep...@gmail.com>
Sent: Friday November 21 2025 8:31:25AM
Subject: Re: [Clayart] Gauges
One more note regarding gauges and gas pressure. The cost of such items is linked to how many of them are used. Usage of WCI gauges is not that common, and thus they are very expensive. On the other hand, high-pressure gauges for LPG regulators are inexpensive because they are on nearly every gas barbecue. Go to the Ward Burner page with gauges, and the WCI gauges are $64 while the 0-30# high-pressure gauge is $14.50.
Just to clarify for those who don't know this, when we refer to low-pressure in gas kilns, we are talking about natural gas or low-pressure LPG. Household natural gas is 7WCI, which is about a quarter pound of pressure. If your kiln is on a separate meter from your household, the gas company is generally willing to boost it up to 11WCI. Low-pressure LPG refers to a setup with a pre-set, non-adjustable regulator, such as is used for household low-pressure LPG systems. High-pressure refers to LPG with an adjustable high-pressure regulator, and is measured in PSI - pounds per square inch. After an overnight preheat at about a half-pound of pressure, my current crossdraft soda kiln stays at 5PSI for the duration of the firing. We have a high-capacity regulator on our 1000-gallon propane tank that is set to 30PSI. A line branches off for the kiln, where there is a high-capacity regulator with a 0-15PSI gauge, while the other branch continues to the house, where there is a preset low-pressure regulator.
All things being relative, the term "high-pressure" is used only because the pressure is very high compared to low-pressure WCI. When I am firing my kiln at 5PSI, the pressure is ten times as high as someone firing a kiln on household natural gas at 7WCI. Industrial burner systems often operate at 10PSI and above, which would be considered very high pressure in gas burner operation.
- Vince
Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincep...@gmail.com <mailto:vincep...@gmail.com>
www.vincepitelka.com <http://www.vincepitelka.com>
https://chathamartistsguild.org/
-----Original Message-----
From: Clayart <clayart...@lists.clayartforum.com <mailto:clayart...@lists.clayartforum.com> > On Behalf Of mel jacobson via Clayart
Sent: Thursday, November 20, 2025 5:19 PM
To: clay clay <cla...@lists.clayartforum.com <mailto:cla...@lists.clayartforum.com> >
Cc: mel jacobson <mel...@mail.com <mailto:mel...@mail.com> >
Subject: [Clayart] Gauges
Gauges,
There seems to be a great deal of giving information based on pressure as seen on gauges for the gas. I do not believe that all gauges read the same numbers. So, from my history and visiting many kilns there is no set markings that indicate exact pressure. Those lines on the gauge front are for you to use and then decide how much you need. When you find a perfect amount of gas, mark the gauge with a sharpy or write it down on the tank. Save the numbers.
I have been to kilns that the owner has been firing the kiln at 12 pounds of pressure he assures me. When you fire the kiln the back pressure from the peep is 20 inches. I turned the gauge down to mark two. There was about 4 inches of back pressure. He fired the kiln for like 7 years with that huge pressure. He said I guy told him 12 pounds. It took him 14 hours to fire and wasted huge amounts of fuel. I fired that kiln in 7 hours, cone ten flat. The pots were perfect. And the pressure gauge on the tank said 63 percent left. We started at 66. I told him “it’s your money, spend it as you want”. I am sure when I left he thought I did hocus/pocus.
Gas is measured in water column. (read about it)
I mark my damper with pencil lines. Line one for early firing to gain heat. Then the mark for light reduction and full reduction. Then a line for closed tight. I fire the entire time with the gauge at two and a half marks. Yesterday I fired my kiln to cone 10 flat in 6 hours and 20 minutes. Lovely oil spot temmoku.
Again, I say, stack your shelves with a stagger. Do not close them up next to each other. If you have a self-argument “should I add these last four pots” say no. Save them for the next firing. Leave room for the heat to travel. Do not build dams. Gas kilns do not need bag walls in most cases.
mel
website: www.melpots.com <http://www.melpots.com>
WWW.clayartarchives.com <http://WWW.clayartarchives.com>
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Ray Bogle via Clayart
I live in Maryland near the Chesapeake Bay in an area that has rich
Native American and early settler history. One of my pottery students
works at Jefferson Patterson Park and Museum (JPP) which is not only a
great place to visit, but is a museum and research/preservation
organization. Earlier this year, part of an old pot was found very
close to JPP and they have been actively seeking information about it
such as origin, age, clay type, firing type, glaze type, maker, etc.
They did some sort of XFR analysis and determined that the primary
compounds were lead, cobalt, nickel, and manganese. So, I thought about
the wealth of knowledge and experience of the people on clayart and that
some of you might enjoy seeing the pot and sharing any insights you
might have. I'll forward any information provided via clayart to JPP for
their consideration. I created a web page on my website with 22 images
provided by JPP showing many details of the piece. Here's the link:
https://madewithclay.com/jpp-pottery Jefferson Patterson Park and Museum
encompasses 560 scenic acres along the Patuxent River in Calvert County,
Maryland, more than 65 identified archaeological sites, and 9,000 years
of documented human occupation. They connect people to the past through
history and archaeology and supports the preservation of Maryland's
cultural and natural resources. Here's the link for more info:
https://jefpat.maryland.gov/Pages/default.aspx
Looking forward to hearing some thoughts on this piece.......Ray
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