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Building a cone 10 outdoor Gas/Salt Kiln


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#1 StokedAboutWoodFiring

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Posted 27 March 2013 - 01:56 AM

Hey guys,

I'm a sophomore at Alfred University, and every spare second (outside of the 3+
hours of clay class I have a day) is spent in our ceramics facilities. This being
said, I've become quite fond of the idea of making my own smallish Salt Kiln in
the woods by my house this upcoming summer. I have access to firebrick (soft
and hard), and have seen a few kilns built, and have access to looking and
investigating the 40+ kilns here on campus, but I still have several questions.

This kiln won't need to be too big, it will only fire work for me and a few friends
from home occasionally. I was thinking around 28 square feet (3x3x4) interior
space. I am going to dig and lay a 3 by 4 foot concrete foundation... then I was
thinking about covering that with cinder blocks (I know to keep the holes running
through them going horizontal to block any moisture from the ground.) I'm
curious, how thick does the floor (of bricks) need to be? I was thinking 1 layer
of soft brick, laying flag, with one layer of hard brick over it, would that be
enough? Also, how thick do the walls/ceiling need to be? Should they all be hard
brick on the interior and soft on the outer layer?

I also have a single burner (like the one in the link I attached)... will that be enough
to heat the kiln (with 28 feet of interior space) to 2300+ degrees?
Burner

Thanks for the help guys, I'm super excited about this. I'm sure I'll have tons of
questions as I actually try to accomplish this project! :blink:src="http://ceramicartsda...ult/blink.gif">
-Ryan

#2 Marcia Selsor

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Posted 27 March 2013 - 07:49 AM

You really can't tell the BTU output from a picture of the flame. You need to know the orifice
size as well as the insulation qualities of your construction. Sounds like a good summer project. Off the top of my head I think the rule of thumb is 14,000 btus per cubic foot for insulation brick construction and 130,000 per cubic foot for hard brick construction. Someone correct me if that is off.

Marcia

#3 justanassembler

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Posted 27 March 2013 - 08:58 AM



This kiln won't need to be too big, it will only fire work for me and a few friends
from home occasionally. I was thinking around 28 square feet (3x3x4) interior
space. I am going to dig and lay a 3 by 4 foot concrete foundation... then I was
thinking about covering that with cinder blocks (I know to keep the holes running
through them going horizontal to block any moisture from the ground.) I'm
curious, how thick does the floor (of bricks) need to be? I was thinking 1 layer
of soft brick, laying flag, with one layer of hard brick over it, would that be
enough? Also, how thick do the walls/ceiling need to be? Should they all be hard
brick on the interior and soft on the outer layer?


I also have a single burner (like the one in the link I attached)... will that be enough
to heat the kiln (with 28 feet of interior space) to 2300+ degrees?
Burner

Thanks for the help guys, I'm super excited about this. I'm sure I'll have tons of
questions as I actually try to accomplish this project! :blink:src="http://ceramicartsda...ult/blink.gif">
-Ryan


Ryan,

Welcome--its fun to see people taking on the challenge of building their own kiln, its a worthwhile endeavor that will teach you a lot about a range of things in ceramics. I'll address your post point by point, and my guess would be that you'll get good input from other folks on here as well.

-Dimensions: You say you want the kiln to be 3x3x4 on the interior, which actually comes out to be 36 cubic feet. The first question that I would ask is what size shelves are you using? This will probably be the easiest way to determine the interior dimensions of your kiln.

-The walls can be six inches thick (two standard brick widths, laid next to one another stretcher bond, for example.) especially if you are laying IFB on the exterior coursing. This will also result in some fuel savings for you since IFB is more insulating than hard brick.

-I'm sure there are differing opinions on this (and most of what I say) so take it with a grain of salt, but I would consider laying 2600 degree IFB directly under your hard brick floor (all the way to the firebox edges) and another layer of 2300 under that. On top of the IFB layers, I would consider laying two layers of hard brick. The concrete block on top of your slab are important to keep the slab isolated from the heat of the kiln, and they also (when laid on their sides) allow you to pass supporting steel under the body of the kiln.

-What kind of hard and soft brick do you have at your disposal? What shapes and dimensions are they? If you want, I have PDF copies of the old AP Green refractory shapes quick reference--helpful when drawing up your designs to have for reference--let me know and I will email them to you.

-Also, with enough patience you should be able to find spec sheets on most any brick you find with a stamp on it. Take the time to do the research before building. As someone who has seen first hand the results of building a kiln out of high silica brick, I assure you that its a worthwhile investment of time and resources.

-With regards to the slab itself, level that thing as well as you can when you pour it--take the time to scree it properly and it will pay off later on in time and frustration savings trying to your coursing. Also remember to include some rebar in it for strength. Even with a "small" kiln, this slab is bearing a good deal of weight.

-Your burner photo doesn't tell me a whole lot about its BTU output as Marcia mentioned. There are tables for calculating combustion requirements in Fred Olsen's The Kiln Book or in Joe Finch's Kiln Building: a Brick by Brick Approach. Both have good information in general and if you're new to building kilns, will be extremely helpful to you as references. Who manufactured your burner? If you take it apart, you should be able to determine your orifice size... You'll need this to do calculations, and you may need to change it out depending on what kind of fuel you are planning on burning. You mentioned you are going to be out in the woods--what sort of fuel do you have on hand there? If you are planning on firing with propane vs nat. gas, they are two different orifice sizes. Additionally, if you are firing with propane you need to consider your tank size. If you are firing off of a large, stationary "pig", you don't need to worry about icing your tanks by accident, however with smaller tanks at high output icing can be an issue. One way of dealing with this is to manifold multiple smaller tanks together.

-Ward Burner has a good technical info section on his site with info about burners, as well as a helpful pipe sizing chart that you might want to look at when it comes to plumbing.

That's what I can think of for the moment... I hope this is helpful--keep us posted with photos and any other questions you might have.

-Michael

#4 Chantay

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Posted 27 March 2013 - 09:59 AM

being interested in this topic I went to Amazon to look at getting the Finch book. Used it is $763!! Guess I'll keep asking questions here.

-chantay
- chantay

#5 justanassembler

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Posted 27 March 2013 - 10:15 AM

being interested in this topic I went to Amazon to look at getting the Finch book. Used it is $763!! Guess I'll keep asking questions here.

-chantay


http://www.nmclay.co...?ic=0-812219848
not sure if its in stock, but they advertise it for 35.00, also, check your library system.

#6 Mark C.

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Posted 27 March 2013 - 01:14 PM

Our salt kiln floor is has 1st layer of hard brick then a soft brick layer then a hrad brick layer for a total of 7 1/2 inches thick.
the kiln is here
http://ceramicartsda...amp;#entry18381
I think one burner makes for a uneven heat situation myself-2 is better and 4 is best for me.
You can use two and get away with it.
I would at least get two burners-
Mark
Mark Cortright
www.liscomhillpottery.com

#7 R Fraser

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Posted 27 March 2013 - 02:58 PM

I just built a kiln of this size and to fire to cone 10 in 8 hours (roughly) it needs 320,000 BTU/Hr input, and I have 2 burners that are fueled by high pressure propane that will put out 150,000 BTU/Hr on 3.5 PSI. I have fired several times now and have to throttle back to make it to 8 hours. The design is mostly a modified Oregon Flat top design as discussed in Nils Lou book the art of firing. The Burner you have pictured looks like a MR 750 or MR 100 style burner, but as pointed out type of fuel and how supplied, your elevation, orifice size, size of supply pipe, regulator capcity all influence final burner output. Marc Ward is a super resource on burner questions.
Here is a link to the thread I started when I finished my kiln;

My First Kiln Build

Good luck!
Richard
So I built a light saber, am I a Jedi now?


#8 Lewis Kiln Development

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Posted 27 March 2013 - 04:32 PM

Ryan,

I attend Alfred University and build kilns professionally. I have a new kiln line coming out very soon. If you would like we can meet up on campus and go over some things.

Desmond Lewis

#9 justanassembler

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Posted 27 March 2013 - 11:05 PM

Ryan,

I attend Alfred University and build kilns professionally. I have a new kiln line coming out very soon. If you would like we can meet up on campus and go over some things.

Desmond Lewis


How about some details for us unwashed masses?




#10 Lewis Kiln Development

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Posted 28 March 2013 - 04:01 AM


Ryan,

I attend Alfred University and build kilns professionally. I have a new kiln line coming out very soon. If you would like we can meet up on campus and go over some things.

Desmond Lewis


How about some details for us unwashed masses?




It is a line of atmospheric kilns. Message me or email me at lewiskilndevelopment@gmail.com for more details.

#11 R Fraser

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Posted 28 March 2013 - 02:21 PM

I too found finches book helpfull. The price on Amazon has got to be an error because that is where I bought mine and it was well less that 700 USD! Amazon was kind enough to offer to buy my used copy for 2.03 USD though! Talk about depreciation.
Richard
So I built a light saber, am I a Jedi now?


#12 AtomicAxe

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Posted 29 March 2013 - 09:38 AM

Can't really say much from what others have said, plus you have the best resource available ... Alfred University. My only suggestion is if you want the kiln to last ... use hard brick on the inside of the kiln. Salt can eat soft brick ... I remember firing a kiln once that you would swear would swell from the pressure because the soft brick was losing some integrity. Ended up taking the department to tear down the kiln and rebuild since it was turning into a liability. Fun summer rebuilding it with the professors.

#13 Marcia Selsor

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Posted 26 October 2013 - 10:51 PM

This kiln won't need to be too big, it will only fire work for me and a few friends from home occasionally. I was thinking around 28 square feet (3x3x4) interior space. I am going to dig and lay a 3 by 4 foot concrete foundation... then I was thinking about covering that with cinder blocks (I know to keep the holes running through them going horizontal to block any moisture from the ground.) I'm curious, how thick does the floor (of bricks) need to be? I was thinking 1 layer of soft brick, laying flag, with one layer of hard brick over it, would that be enough? Also, how thick do the walls/ceiling need to be? Should they all be hard brick on the interior and soft on the outer layer?I also have a single burner (like the one in the link I attached)... will that be enough to heat the kiln (with 28 feet of interior space) to 2300+ degrees?BurnerThanks for the help guys, I'm super excited about this. I'm sure I'll have tons of questions as I actually try to accomplish this project! :blink:src="http://ceramicartsda...link.gif">-Ryan

Ryan,Welcome--its fun to see people taking on the challenge of building their own kiln, its a worthwhile endeavor that will teach you a lot about a range of things in ceramics. I'll address your post point by point, and my guess would be that you'll get good input from other folks on here as well.-Dimensions: You say you want the kiln to be 3x3x4 on the interior, which actually comes out to be 36 cubic feet. The first question that I would ask is what size shelves are you using? This will probably be the easiest way to determine the interior dimensions of your kiln.-The walls can be six inches thick (two standard brick widths, laid next to one another stretcher bond, for example.) especially if you are laying IFB on the exterior coursing. This will also result in some fuel savings for you since IFB is more insulating than hard brick.-I'm sure there are differing opinions on this (and most of what I say) so take it with a grain of salt, but I would consider laying 2600 degree IFB directly under your hard brick floor (all the way to the firebox edges) and another layer of 2300 under that. On top of the IFB layers, I would consider laying two layers of hard brick. The concrete block on top of your slab are important to keep the slab isolated from the heat of the kiln, and they also (when laid on their sides) allow you to pass supporting steel under the body of the kiln. -What kind of hard and soft brick do you have at your disposal? What shapes and dimensions are they? If you want, I have PDF copies of the old AP Green refractory shapes quick reference--helpful when drawing up your designs to have for reference--let me know and I will email them to you.-Also, with enough patience you should be able to find spec sheets on most any brick you find with a stamp on it. Take the time to do the research before building. As someone who has seen first hand the results of building a kiln out of high silica brick, I assure you that its a worthwhile investment of time and resources.-With regards to the slab itself, level that thing as well as you can when you pour it--take the time to scree it properly and it will pay off later on in time and frustration savings trying to your coursing. Also remember to include some rebar in it for strength. Even with a "small" kiln, this slab is bearing a good deal of weight.-Your burner photo doesn't tell me a whole lot about its BTU output as Marcia mentioned. There are tables for calculating combustion requirements in Fred Olsen's The Kiln Book or in Joe Finch's Kiln Building: a Brick by Brick Approach. Both have good information in general and if you're new to building kilns, will be extremely helpful to you as references. Who manufactured your burner? If you take it apart, you should be able to determine your orifice size... You'll need this to do calculations, and you may need to change it out depending on what kind of fuel you are planning on burning. You mentioned you are going to be out in the woods--what sort of fuel do you have on hand there? If you are planning on firing with propane vs nat. gas, they are two different orifice sizes. Additionally, if you are firing with propane you need to consider your tank size. If you are firing off of a large, stationary "pig", you don't need to worry about icing your tanks by accident, however with smaller tanks at high output icing can be an issue. One way of dealing with this is to manifold multiple smaller tanks together. -Ward Burner has a good technical info section on his site with info about burners, as well as a helpful pipe sizing chart that you might want to look at when it comes to plumbing.That's what I can think of for the moment... I hope this is helpful--keep us posted with photos and any other questions you might have.-Michael
Actually standard bricks are 9 x 4 1/2 x 2 3/4
marcia




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