Vince Pitelka on tue 15 apr 08
Jon Byler wrote:
"Does anyone have any recommendations/suggestions for building the
base of a kiln? I am building on slab, but want to raise everything
up a bit for ease of firing and to protect the slab. The klin will
be about 36 cu foot box, with hard brick interior and soft brick
exterior. I am looking at building with cinder blocks on their
sides, and was wondering if it is recommended to use mortar or to
just lay them up dry as long as everything stays level? Also, is it
prudent in such a kiln to use IFB under the hardbricks in the floor
to keep the heat in, or can you just use two layers of hardbrick?"
Jon -
I know that some people advocate using the cinder blocks on their sides, but
I strongly oppose that idea. Some cinder blocks being made today are quite
crumbly, and do not have the strength to support a kiln when laid on their
sides. Imagine what a disaster it would be if you built a kiln supported by
cinder blocks on their sides, and later on the cinder blocks started to
collapse. Imagine that happening during a firing.
If you build a proper floor, then there is no heat buildup at that level,
and no need for ventilation. My favorite floor is cinder blocks laid with
the holes face up, and then a layer of cement board - the stuff they use in
place of drywall when installing ceramic tile in a shower or bath surround.
It is reinforced with fiberglass and very strong, easily capable of spanning
the holes in the cinderblock. No need to use mortar. Just lay out your
foundation footprint with chalk or chalk-line, and then use a combination of
standard cinder blocks and cap blocks to lay up the foundation, and then the
layer of cement board. For a kiln floor, I like to use two layers of IFB
laid flat, and then one layer of hardbrick laid flat as a hotface floor to
support the kiln set.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
KATHI LESUEUR on tue 15 apr 08
On Apr 15, 2008, at 4:43 PM, jonathan byler wrote:
> Does anyone have any recommendations/suggestions for building the
> base of a kiln? I am building on slab, but want to raise everything
> up a bit for ease of firing and to protect the slab. The klin will
> be about 36 cu foot box, with hard brick interior and soft brick
> exterior. I am looking at building with cinder blocks on their
> sides, and was wondering if it is recommended to use mortar or to
> just lay them up dry as long as everything stays level? Also, is it
> prudent in such a kiln to use IFB under the hardbricks in the floor
> to keep the heat in, or can you just use two layers of hardbrick?
My kiln, which has been in it's present location for eighteen years,
is built on cinder block laid on their sides on a cement slab. This
allows air to flow through them (and gives the chipmunk a place to
build a nest). I have a layer of IBF on the cinder block and then
hard brick floor. It's held up well for me.
Kathi
>
>
jonathan byler on tue 15 apr 08
Does anyone have any recommendations/suggestions for building the
base of a kiln? I am building on slab, but want to raise everything
up a bit for ease of firing and to protect the slab. The klin will
be about 36 cu foot box, with hard brick interior and soft brick
exterior. I am looking at building with cinder blocks on their
sides, and was wondering if it is recommended to use mortar or to
just lay them up dry as long as everything stays level? Also, is it
prudent in such a kiln to use IFB under the hardbricks in the floor
to keep the heat in, or can you just use two layers of hardbrick?
thanks,
jon
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
Steve Mills on tue 15 apr 08
I use dry laid hollow blocks under my kilns; it stops rising damp, and protects the slab (or in the case of one Kiln I built asphalt) underneath.
Steve
Bath
UK
jonathan byler wrote:
Does anyone have any recommendations/suggestions for building the
base of a kiln? I am building on slab, but want to raise everything
up a bit for ease of firing and to protect the slab. The klin will
be about 36 cu foot box, with hard brick interior and soft brick
exterior. I am looking at building with cinder blocks on their
sides, and was wondering if it is recommended to use mortar or to
just lay them up dry as long as everything stays level? Also, is it
prudent in such a kiln to use IFB under the hardbricks in the floor
to keep the heat in, or can you just use two layers of hardbrick?
thanks,
jon
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
______________________________________________________________________________
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Nobody Special on tue 15 apr 08
On Tue, 15 Apr 2008 15:43:05 -0500, jonathan byler wrote:
>Does anyone have any recommendations/suggestions for building the
>base of a kiln? I am building on slab, but want to raise everything
>up a bit for ease of firing and to protect the slab.
Jon...
For the last two kilns I had a hand in building, we used cinder blocks on
their sides laid up dry. I bought the three-chambered variety from a local
concrete block manufacturer, as they are significantly stronger than the
two-chambered blocks typically found in home centers. IIRC, the
three-chambered blocks were only about $1.25 more than the two-chambered
variety. One of the kilns has been up for about 5 years now, and the other
about 3, and so far nothing has moved. We did use a layer of IFB for the
first layer of the floor, and hard brick for the second.
Hope it helps.
...James
Curtis Benzle on tue 15 apr 08
Hi Jon: I have never mortared the block with no trouble and I think the
blanket
would just squish and loose its insulating quality. I have only used the
bricks.
Curt
On Tue, Apr 15, 2008 at 2:43 PM, jonathan byler wrote:
> Does anyone have any recommendations/suggestions for building the
> base of a kiln? I am building on slab, but want to raise everything
> up a bit for ease of firing and to protect the slab. The klin will
> be about 36 cu foot box, with hard brick interior and soft brick
> exterior. I am looking at building with cinder blocks on their
> sides, and was wondering if it is recommended to use mortar or to
> just lay them up dry as long as everything stays level? Also, is it
> prudent in such a kiln to use IFB under the hardbricks in the floor
> to keep the heat in, or can you just use two layers of hardbrick?
>
> thanks,
>
> jon
>
>
> jon byler
> 3-D Building Coordinator
> Art Department
> Auburn University, AL 36849
>
>
> ______________________________________________________________________________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here:
> http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
>
larry on tue 15 apr 08
In my experience we build on a raised welded steel frame, and have develope=
d a 1 hour plus or minus fast fire kiln (cone 10). It is a modified side dr=
aft kiln with three burners using about $1.00 in gas per firing. The kiln i=
s completely constructed from insulating fire brick only 1 brick thick and =
since it fires in one hour the brick do not have enough time to get hot. Si=
nce the kiln is on a welded steel frame if it ever needs to be moved it is =
possible without destroying it. Currently, we are working a the patent for =
the kiln and expect to have it on the market within one year. By the way we=
have used this kiln for over 20 years with thousands of firings. Larry=0D=
=0A=0D=0A----------------------------------------=0D=0AFrom: "KATHI LESUEUR=
" =0D=0ASent: Tuesday, April 15, 2008 9:54 PM=0D=
=0ATo: CLAYART@LSV.CERAMICS.ORG=0D=0ASubject: Re: kiln foundations =0D=0A=
=0D=0AOn Apr 15, 2008, at 4:43 PM, jonathan byler wrote:=0D=0A> Does anyone=
have any recommendations/suggestions for building the=0D=0A> base of a kil=
n? I am building on slab, but want to raise everything=0D=0A> up a bit for=
ease of firing and to protect the slab. The klin will=0D=0A> be about 36 =
cu foot box, with hard brick interior and soft brick=0D=0A> exterior. I am=
looking at building with cinder blocks on their=0D=0A> sides, and was wond=
ering if it is recommended to use mortar or to=0D=0A> just lay them up dry =
as long as everything stays level? Also, is it=0D=0A> prudent in such a ki=
ln to use IFB under the hardbricks in the floor=0D=0A> to keep the heat in,=
or can you just use two layers of hardbrick?=0D=0A=0D=0AMy kiln, which has=
been in it's present location for eighteen years,=0D=0Ais built on cinder =
block laid on their sides on a cement slab. This=0D=0Aallows air to flow th=
rough them (and gives the chipmunk a place to=0D=0Abuild a nest). I have a =
layer of IBF on the cinder block and then=0D=0Ahard brick floor. It's held =
up well for me.=0D=0A=0D=0AKathi=0D=0A>=0D=0A>=0D=0A=0D=0A_________________=
_____________________________________________________________=0D=0AClayart =
members may send postings to: clayart@lsv.ceramics.org=0D=0A=0D=0AYou may=
look at the archives for the list, post messages, change your=0D=0Asubscri=
ption settings or unsubscribe/leave the list here: http://www.acers.org/ci=
c/clayart/=0D=0A=0D=0AModerator of the list is Mel Jacobson who may be reac=
hed at melpots2@visi.com=0D=0A=0D=0A
Mary & Wes Handrow on wed 16 apr 08
I have never had a failure laying the blocks on their side, even under the
chimney, which is by far the heaviest load the blocks will have to hold. As
to how I get a level base, a thin layer of sand under the blocks and check
them as they are laid with a level. The last one was dead level and smooth
as a baby's bottom.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of jonathan byler
Sent: Wednesday, April 16, 2008 12:17 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: kiln foundations
with no mortar, how do you guys level stuff, or do you just get the
pick of the cement blocks?
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
Vince Pitelka on wed 16 apr 08
Richard Aerni wrote:
"Oh dear, I really hate to take issue with anything that my friend
Dannon says, she being so wonderful, and informative and all...
...but, I've always built my kilns on cinder block laid sideways, to keep
air moving under the kiln, and never had a problem. First kiln built that
way in 1980, fired probably 1000 times, last kiln built 2004, fired almost
100 times, and in the ones in between, nary a problem. My kilns are car
kilns, and I was concerned with the heat under the kiln car melting the
lubricating grease out of the wheels under the cart. Never had any melting
or a problem with the wheels.
These kilns ranged in size from 100 cubic feet down to 45 cubic feet, hard
brick as well as soft brick. Never had a block fail."
Richard -
I am very glad to hear that you never had any problem with those kilns. The
first major kiln I built was a 100-cubic-foot car kiln in my studio in
Northern California in 1979, and I laid the cinder block as I like to do,
with the holes facing up. The car floor was composed of two layers of
softbrick laid flat and then two inches of hard castable, and I never had
any heat accumulation beneath the car floor. It just never got hot down
there. In fact, with two layers of soft brick and a hardbrick hotface
floor, I have never experienced any appreciable heat buildup under the
floor, and have never seen any need for ventilation in that area.
What I have seen recently is a lot of inferior, crumbly softbrick on the
market today, and to me it just makes no sense to take chances, when there
doesn't seem to be any compelling reason to lay the bricks on their sides.
Please understand that this is just my own opinion, and I am just relating
my own experience. On all of the many kilns I have built, I have always
laid the cinder block with the holes face up, and have never experienced any
downside to that practice.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
John Britt on wed 16 apr 08
Jonathan,
I am with Shane, Richard, etc. on the use of cinderblock on its side. I
have done it that way for years and had no problems. The cinderblock is
strongest sitting with the holes up of course, and that is the way it is
designed to be used, but there is not enough weight to crush the
cinderblock. I have even seen cinderblock turned on its side supporting a
hard brick chimney and that did not crush after 12 years. That is a lot of
weight!
I usually use cement board over the cinderblock and that helps with the
uneveness of the block. If the cement slab is really slanted then I either
use fire clay mixed with water on the first layer of the floor to level
it. Or I stack two layers of cinderblock and use mortar to get them level.
But that is only in really bad situations. I had one with a 2" rise.
Hope it helps,
John Britt
www.johnbrittpottery.com
Frank Colson on wed 16 apr 08
The most reliable and consistant installation I have used for prevention of
kiln bottom heat penetration, irregardless of the sub-base, is 1/4" ceramic
fiber "board"! Once I built a kiln in Lima, Peru, on an adobe clay
base.which provided excellent installation at regular C10 firings
. One of my studio base 20 cu.ft. gas kilns has been operational to this
day, on concrete block sub-base for more than 4 decades!
Frank Colson/COLSON STUDIO
www.R2D2u.com
----- Original Message -----
From: "Vince Pitelka"
To:
Sent: Tuesday, April 15, 2008 6:18 PM
Subject: Re: kiln foundations
> Jon Byler wrote:
> "Does anyone have any recommendations/suggestions for building the
> base of a kiln? I am building on slab, but want to raise everything
> up a bit for ease of firing and to protect the slab. The klin will
> be about 36 cu foot box, with hard brick interior and soft brick
> exterior. I am looking at building with cinder blocks on their
> sides, and was wondering if it is recommended to use mortar or to
> just lay them up dry as long as everything stays level? Also, is it
> prudent in such a kiln to use IFB under the hardbricks in the floor
> to keep the heat in, or can you just use two layers of hardbrick?"
>
> Jon -
> I know that some people advocate using the cinder blocks on their sides,
> but
> I strongly oppose that idea. Some cinder blocks being made today are
> quite
> crumbly, and do not have the strength to support a kiln when laid on their
> sides. Imagine what a disaster it would be if you built a kiln supported
> by
> cinder blocks on their sides, and later on the cinder blocks started to
> collapse. Imagine that happening during a firing.
>
> If you build a proper floor, then there is no heat buildup at that level,
> and no need for ventilation. My favorite floor is cinder blocks laid with
> the holes face up, and then a layer of cement board - the stuff they use
> in
> place of drywall when installing ceramic tile in a shower or bath
> surround.
> It is reinforced with fiberglass and very strong, easily capable of
> spanning
> the holes in the cinderblock. No need to use mortar. Just lay out your
> foundation footprint with chalk or chalk-line, and then use a combination
> of
> standard cinder blocks and cap blocks to lay up the foundation, and then
> the
> layer of cement board. For a kiln floor, I like to use two layers of IFB
> laid flat, and then one layer of hardbrick laid flat as a hotface floor to
> support the kiln set.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net; wpitelka@tntech.edu
> http://iweb.tntech.edu/wpitelka
>
> ______________________________________________________________________________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here:
> http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
Dannon Rhudy on wed 16 apr 08
> Jon Byler wrote:
> "Does anyone have any recommendations/suggestions for building the
> base of a kiln? I am building on slab, but want to raise everything
> up a bit for ease of firing and to protect the slab.
am looking at building with cinder blocks on their
> sides, ..........
I agree with Vince on this matter. Current cinder
block is really meant to be used with the holes up,
not sideways. All the stress tests are done that way
and there's only experience to tell if they have sufficient
strength laid on the side. Finding out it doesn't work
is not an experience you want to have. I've done it
both ways, and never had a problem, but I have certainly
noted that the quality of cinder block is not what it was.
If you are concerned with ventilation, then a piece of
expanded metal lath can be laid down on top of the
cinder block, with or without the cement board that
Vince recommends. I never use mortar.
regards
Dannon Rhudy
Richard Aerni on wed 16 apr 08
Oh dear, I really hate to take issue with anything that my friend
Dannon says, she being so wonderful, and informative and all...
...but, I've always built my kilns on cinder block laid sideways, to keep
air moving under the kiln, and never had a problem. First kiln built that
way in 1980, fired probably 1000 times, last kiln built 2004, fired almost
100 times, and in the ones in between, nary a problem. My kilns are car
kilns, and I was concerned with the heat under the kiln car melting the
lubricating grease out of the wheels under the cart. Never had any melting
or a problem with the wheels.
These kilns ranged in size from 100 cubic feet down to 45 cubic feet, hard
brick as well as soft brick. Never had a block fail.
Best wishes,
Richard Aerni
Rochester, NY
On Wed, 16 Apr 2008 07:00:28 -0500, Dannon Rhudy wrote:
>> Jon Byler wrote:
>> "Does anyone have any recommendations/suggestions for building the
>> base of a kiln? I am building on slab, but want to raise everything
>> up a bit for ease of firing and to protect the slab.
> am looking at building with cinder blocks on their
>> sides, ..........
>
>I agree with Vince on this matter. Current cinder
>block is really meant to be used with the holes up,
>not sideways. All the stress tests are done that way
>and there's only experience to tell if they have sufficient
>strength laid on the side. Finding out it doesn't work
>is not an experience you want to have. I've done it
>both ways, and never had a problem, but I have certainly
>noted that the quality of cinder block is not what it was.
>If you are concerned with ventilation, then a piece of
>expanded metal lath can be laid down on top of the
>cinder block, with or without the cement board that
>Vince recommends. I never use mortar.
>
>regards
>
>Dannon Rhudy
>
>______________________________________________________________________________
>Clayart members may send postings to: clayart@lsv.ceramics.org
>
>You may look at the archives for the list, post messages, change your
>subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.com
gary navarre on wed 16 apr 08
Ya Jon,
As long as you insulate the cinder block from the
hard brick floor with IFB and or a couple inches of
ceramic fiber board the heat won't damage the block. I
found out what happens to "block" under the floor
without much insulation when I took my last kiln
apart...
http://public.fotki.com/GindaUP/ca/kpap/kbhd/
My present location allows me to experiment with
following some of the recommendations Cardew and Leach
make regarding crushed rock rather than a slab.
Although it took some time and labor I think this will
prove to work just fine and I saver a lot of money.
Something I noticed while looking over some of the
early shots of this kiln is the primary rock and stone
under the gravel looks like one of my other favorite
media, a guitar...
http://public.fotki.com/GindaUP/ca/kpap/nvhga/fi3.html
Geeze that was a while ago eh, 2004. Rick came by
today and we took the covering off cause most all the
snow is gone and I can pick up where we left off when
winter came along.
Good lick with your project and stay in there eh!
--- jonathan byler wrote:
> Does anyone have any recommendations/suggestions for
> building the
> base of a kiln? I am building on slab, but want to
> raise everything
> up a bit for ease of firing and to protect the slab.
> The klin will
> be about 36 cu foot box, with hard brick interior
> and soft brick
> exterior. I am looking at building with cinder
> blocks on their
> sides, and was wondering if it is recommended to use
> mortar or to
> just lay them up dry as long as everything stays
> level? Also, is it
> prudent in such a kiln to use IFB under the
> hardbricks in the floor
> to keep the heat in, or can you just use two layers
> of hardbrick?
>
> thanks,
>
> jon
Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://public.fotki.com/GindaUP/
http://www.youtube.com/GindaUP
____________________________________________________________________________________
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shane mickey on wed 16 apr 08
jonathan,
you can use cinderblock on their side and without mortar that is common =
practice.=20
also run your angle iron supports all the way down to the slab to hold =
the cinderblock in place also.
you may need to cut or just space out the blocks to make them the same =
actual footprint
of your kiln. as to soft brick under the floor it is a good idea if your =
only doing two layers
of floor to make the bottom one insulating helps protect the block as =
they are concrete
also and can pop due to heat. and as i always say, start on level/plumb =
stay on and=20
the kiln goes much smoother.
shane mickey
shane mickey pottery and kiln design services
jonathan byler on wed 16 apr 08
with no mortar, how do you guys level stuff, or do you just get the
pick of the cement blocks?
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 16, 2008, at 7:00 AM, Dannon Rhudy wrote:
>> Jon Byler wrote:
>> "Does anyone have any recommendations/suggestions for building the
>> base of a kiln? I am building on slab, but want to raise everything
>> up a bit for ease of firing and to protect the slab.
> am looking at building with cinder blocks on their
>> sides, ..........
>
> I agree with Vince on this matter. Current cinder
> block is really meant to be used with the holes up,
> not sideways. All the stress tests are done that way
> and there's only experience to tell if they have sufficient
> strength laid on the side. Finding out it doesn't work
> is not an experience you want to have. I've done it
> both ways, and never had a problem, but I have certainly
> noted that the quality of cinder block is not what it was.
> If you are concerned with ventilation, then a piece of
> expanded metal lath can be laid down on top of the
> cinder block, with or without the cement board that
> Vince recommends. I never use mortar.
>
> regards
>
> Dannon Rhudy
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://
> www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
Edouard Bastarache Inc. on wed 16 apr 08
Dannon,
"Current cinder block is really meant to be used
with the holes up, not sideways."
That is the way they start building 90-150 ton
furnaces
in the steel industry.
When I built my last kiln I wanted to put them
sideways
but my industrial bricklayer told me :"You put
them up
right or get yourself another bricklayer".
He also told me to fill the holes with "mortar
sand"
up to 1" lower than the rim so we would make an
even
mortar slab before building the bottom.
I hired him for the bottom and the chimney.
You can see a picture here :
http://gazkiln.blogspot.com/
Gis revido,
(A la revoyure)
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.pshcanada.com/Toxicology.htm
http://www.flickr.com/photos/30058682@N00/
http://www.flickr.com/photos/potier/20321056/
http://perso.orange.fr/smart2000/livres.htm
http://myblogsmesblogs.blogspot.com/
Dannon Rhudy on thu 17 apr 08
Edouard said:
> That is the way they start building 90-150 ton
> furnaces
> in the steel industry.
> When I built my last kiln I wanted to put them
> sideways
> but my industrial bricklayer told me :"You put
> them up
> right or get yourself another bricklayer".
Very handsome kiln, Edouard.
Can't blame the bricklayer for his
position. If he's responsible (here he
would be) then he's gotta have the
authority. Don't know how you guys
are on law suits, way up yonder. Here,
they are a plague.
best
Dannon
shane mickey on thu 17 apr 08
jon et al
i believe most of us would say we start with a very level slab
to begin with and the blocks should lay level then. if the slab=20
is not level then you need to make the block level, or god forbid=20
the slab level. i have done both, many ways to do this, too many=20
to list, if your off by just and 1/8 " or so in one area i find that
asphalt shingles work well, if its a bigger problem then airsetting =
mortar
is in need. as to block on side or used the way they are designed i=20
think vince has a great point, i always lay mine on their side
for the air circulation, but a safer bet would be holes up with cement
board on top, careful with the floor thickness when using cement board
at least for the first firing, as that stuff comes very wet sometimes =
and
may not be fully cured! I use to use two layers of ifb but ran some=20
thermal numbers and find two layers of hard and one(on bottom)layer of
ifb to do fine, plus this can save money as ifb are genreally more =
expensive
than hard brick. hope that helps.
shane mickey
kiln design and building services
Steve Mills on thu 17 apr 08
A bed of well compacted sand underneath the blocks, a staight edge, and a large wooden mallet is a great help in ironing out an uneven surface.
Steve
Bath
UK
jonathan byler wrote:
with no mortar, how do you guys level stuff, or do you just get the
pick of the cement blocks?
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
---------------------------------
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Vince Pitelka on thu 17 apr 08
Someone wrote:
"I have never had a failure laying the blocks on their side, even under the
chimney, which is by far the heaviest load the blocks will have to hold. As
to how I get a level base, a thin layer of sand under the blocks and check
them as they are laid with a level. The last one was dead level and smooth
as a baby's bottom."
This is the second post from someone saying "I have always laid my blocks on
their sides and I have never had a kiln failure." or "My kiln has been fired
1000 times and the foundation is built with the blocks on their sides."
SO WHAT? You can build the foundation any way you want to, but why in the
world would anyone choose to build a kiln foundation with the blocks on
their sides when there is no reason to do so, and when it is inherently
safer and more stable to build with the holes facing upwards? Some people
talk about ventilation beneath the kiln, but I have yet to see any
compelling evidence that heat accumulates there if you build the kiln floor
properly, or that ventilation beneath the kiln serves any other purpose.
This is just my opinion, and again, you can build the foundation however you
wish. I am just curious if anyone actually has any concrete (bad pun)
evidence that laying the blocks on their sides serves any real purpose.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Vince Pitelka on thu 17 apr 08
Just as a side note to this discussion, way back around 1969, Steve Hyman
built a catenary arch crossdraft gas salt kiln up on Fickle Hill above
Arcata, California, from hardbrick salvaged from the sawmills. Back then,
the abundant sawmills around Humboldt County had piles of cast-off hardbrick
from re-lining their boilers. Every once in a while an employee would take
some home to build a patio, but no one else wanted them until us potters
came along. At any rate, Steve built this kiln with only two thicknesses of
hardbrick (5") laid flat on a fresh concrete slab. We were getting close to
the end, and they had just charged salt and were standing back to let the
kiln regain temperature before pulling another draw-ring when the slab
exploded. Because that hardbrick kiln was radiating so much heat we were all
standing well away from it. The whole kiln just lifted up in the air about
a foot, and for just a split second you could actually see the red-hot pots
between the bricks. Then the whole thing came crashing down into a red-hot
heap, spitting shards of concrete as the impacted moisture continued to
burst. We all stood there in silence, and then Steve said "I think this
calls for more beer."
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Michael Wendt on thu 17 apr 08
Please pardon my need to inject math
into the subject.
Standard cement block webs are
about 1" thick and blocks are about
7.5" tall so each web contributes
7.5 square inches of support to the
kiln x 4 webs per block for a total
of 30 square inches per block.
Standard concrete is rated at 3000
pounds per square inch compressive
strength.
Below is a table of values a single
block on its side could support with different
assumed strengths:
100 psi 3000 pounds per block on side
500 psi 15000 pounds per block on side
1000 psi 30000 pounds per block on side
3000 psi 90000 pounds per block on side
even if the blocks are quite weak, they are
plenty strong on their sides and also have the
smooth face with no holes to contend with.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Paul Herman on thu 17 apr 08
Hello All,
It's interesting reading everyones varying opinions about laying
cement block on it's side, with the air holes going horizontally. I
must say I think it's not a good idea, even though several of you
swear it's fine.
I know of an occasion where the sideways block DID fail, with almost
catastrophic results. A friend of mine attended the inaugural firing
of a large naborigama in the south east US. The kiln had a dogi
chamber with three large catenary chambers, and the whole shebang had
been built on an artificial hill of cement blocks. The massive hard
brick chimney rested upon layers of sideways block.
As the new kiln heated up it started to swell, as kilns are wont to
do. Especially expanding along it's length, it pushed up the hill
against the chimney. By this time the first layer of block under the
chimney had cracked, from heat or pressure or both, and the broken
block started to tip toward the uphill side of the kiln. The potter
noticed, and stuck some heavy steel beams through the "air passages"
of the block, and blocked up the ends of the beams, barely avoiding a
catastrophic collapse of the hot chimney. After that firing he
replaced the chimney foundation with something solid, I think solid
cement block.
So, I think solid concrete or earth foundations are the way to go. If
you are in a wet climate, perhaps use crushed rock, ala Cardew.
Good solid foundations,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
Bill Merrill on thu 17 apr 08
Jon,
Jonathon
I have built about 50 stoneware, salt and wood kilns over a 45 year
period. So, any help I can offer you please feel free to write me
directly and I try to be of help. Dave Shaner was a potter who really
helped me with kiln construction and firing high fire kilns. You may be
bombarded with info, so choose carefully.
When I start a kiln, I lay the kiln shelves on the floor and then add
walls 1 row of brick, etc to make sure the combustion area and bag wall
have enough room. You can leave space for burner ports and flue. Now
you have the footprint of the kiln. =20
If you are building a stoneware kiln I would use K-23 insulators for the
walls. It is a little harder to build a kiln with a hard brick interior
and a soft brick exterior. To keep the walls from separating when using
all soft brick walls I use 3 rows of stretcher style construction and
then one row of stringer type construction. The stringer row holds the
2 rows together. Then I use 3-4 rows of the stretcher coarse then
repeat the stringer rows and stringer rows.=20
I can send pictures etc. also. =20
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of jonathan
byler
Sent: Wednesday, April 16, 2008 10:17 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: kiln foundations
with no mortar, how do you guys level stuff, or do you just get the
pick of the cement blocks?
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 16, 2008, at 7:00 AM, Dannon Rhudy wrote:
>> Jon Byler wrote:
>> "Does anyone have any recommendations/suggestions for building the
>> base of a kiln? I am building on slab, but want to raise everything
>> up a bit for ease of firing and to protect the slab.
> am looking at building with cinder blocks on their
>> sides, ..........
>
> I agree with Vince on this matter. Current cinder
> block is really meant to be used with the holes up,
> not sideways. All the stress tests are done that way
> and there's only experience to tell if they have sufficient
> strength laid on the side. Finding out it doesn't work
> is not an experience you want to have. I've done it
> both ways, and never had a problem, but I have certainly
> noted that the quality of cinder block is not what it was.
> If you are concerned with ventilation, then a piece of
> expanded metal lath can be laid down on top of the
> cinder block, with or without the cement board that
> Vince recommends. I never use mortar.
>
> regards
>
> Dannon Rhudy
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
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________________________________________________________________________
______
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here:
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Moderator of the list is Mel Jacobson who may be reached at
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Vince Pitelka on fri 18 apr 08
Michael Wendt wrote:
"Below is a table of values a single
block on its side could support with different
assumed strengths:
100 psi 3000 pounds per block on side
500 psi 15000 pounds per block on side
1000 psi 30000 pounds per block on side
3000 psi 90000 pounds per block on side
even if the blocks are quite weak, they are
plenty strong on their sides and also have the
smooth face with no holes to contend with."
Michael -
It would be nice if all cinder blocks really lived up to those specs, but of
course they do not. Some are incredibly brittle and crumbly. They might
serve just fine in construction when the holes are facing upwards, but on
their sides they would be risky, even when just supporting the weight of a
kiln. None of this "evidence" accomplishes anything in defending the case
of kiln foundation blocks on their sides. A few sheets of cement board are
a minimal expense to cover the blocks facing upwards. I am still waiting
for some sort of compelling evidence that placing the blocks on their sides
sufficient advantage to make it worth the risk. I have never seen any
advantage at all to having the blocks on their sides, as long as the kiln
floor is built properly.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Edouard Bastarache Inc. on fri 18 apr 08
Vince,
I heard of a girl in Quebec who build a casted
concrete
base with steel rods over a concrete floor.
At the first firing the base exploded probably
because
of moisture remaining in the base.
Eveything was kaput...
So, good design is important.
I prefer the design used in the steel ibndustry
Gis revido,
(A la revoyure)
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.pshcanada.com/Toxicology.htm
http://www.flickr.com/photos/30058682@N00/
http://www.flickr.com/photos/potier/20321056/
http://perso.orange.fr/smart2000/livres.htm
http://myblogsmesblogs.blogspot.com/
jonathan byler on fri 18 apr 08
i saw it in a book once. does that count???
seriously, vince, thanks for the tips. now we just need to take
delivery of the last load of bricks, and more importantly finish
jumping through the bureaucratic hoops needed to get the hole in the
roof and the proper gas regulator, and we might just get this kiln
built.
jon
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 17, 2008, at 9:53 PM, Vince Pitelka wrote
>
> I am just curious if anyone actually has any concrete (bad pun)
> evidence that laying the blocks on their sides serves any real
> purpose.
> - Vince
>
David Woof on sat 19 apr 08
Hi Vince and Michael, I know you both know what you are speaking of, so I=
just wish to clarify seemingly interchangeable terms that might confuse so=
me folks new to constructing kilns, or constructing anything.=20
=20
Cinder blocks are composed of cinders, either ground up industrial coal fir=
ed clinker waste or mined from natural mountains of volcanic cinders. These=
cinders are cemented together with enough concrete to give them a ridged s=
hape and meet certain and varied construction ratings. One can see the cind=
er matrix.=20
=20
True concrete blocks are an entirely different block, denser. harder, thick=
er in internal dimensions, considerably stronger, and heavier in actual we=
ight than cinder block.
_________________________________________
=20
I can add to Edouard's mention of a cast concrete base exploding. Quite so=
me years ago a friend decided he would fly in the face of conventional wisd=
om and forego the raised kiln floor and so with a brick floor laid directly=
on the poured concrete pad he proceeded to build his kiln.
=20
He had cone 9 down when the heat had penetrated to the concrete and it expl=
oded. He was walking about 30 feet away when he heard the explosion and tu=
rned to see, and duck, a basket ball size glowing pot that ignited his wint=
er lawn after the near miss to his head. the kiln fell back in on itself an=
d became a monument of fused pots, bricks and concrete shards.
=20
It is good to see the questions from new folks planning and desiring to bui=
ld kilns. We used to ride the learning curve with the seat of our pants to=
gain the information that is now so abundant.
Risk is the well worn tool for those who quest for new discoveries, but it'=
s wise to search the accumulated knowledge and know the consequences of est=
ablished rules broken before forging ahead into the unknown.
=20
Best regards to all
=20
David
=20
David Woof Studio
=20
Clarkdale, Az. =20
=20
=20
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John Britt on sat 19 apr 08
Vince,
I have not seen any evidence that having the cinderblocks on their sides
is a problem...for IFB kilns. All the stories involve hard bricks, large
chimenys, massive wood kilns, etc. Unless, of course, I missed something.
The problem is that you want everyone to believe the logic of your method
and switch to it.( and your logic is fine.) But there is no problem to
the current method which is, in fact, working very well.
You are only injecting the fear that it may not work. But to get people to
change from the known, you need a compelling reason. (It has always worked
in the past so why should I change?)Is the possibiility that it may not
work enough? Inspite, of the evidence that it does work.
But, because what you say makes logical sense, I will try your method on
my next kiln, and see if there is any discernable difference. I do use the
cement board anyway and am always testing for new methods and reasons.
Will let you know,
John Britt
www.johnbrittpottery.com
Michael Wendt on sat 19 apr 08
Vince,
In order to be sold for construction,
blocks have to meet minimum codes.
The Uniform Building Code book I have
(Table 24-4) lists the minimum design load
at 150 PSI. Typical manufacturing wants to
exceed that value by a margin to avoid
liability issues. Further, the webs constitute
63% of the section area of the block.
The sides only add 37% more cross
sectional area.
Now as to the why on their sides:
Blocks sitting upright on a concrete slab
capped with cement board are closed
cells. Heat radiated through the bottom
of the kiln will build up when compared
to blocks laid on their sides so that air
flow can cool the slab.
Its funny that so many people have
mentioned experiencing concrete explosions.
When I worked in a foundry, that was the main
concern with respect to hot metal spills.
Floors were covered deep with sand to
avoid metal reaching the concrete which
explodes like a grenade when heated too
quickly and shoots chunks out.
Concrete is never dry. Like clay, it contains
chemically combined water which it releases
as steam if heated.
Since blocks are plenty strong on their sides and
since it would only take one explosion to injure
you an cause you financial loss, I see no reason
to take a chance and set them upright.
If you are worried about seismic stability, run
the end courses 90 degrees to the floor deck
so you eliminate the flexural stability issue
in both directions.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Vince wrote
Michael -
It would be nice if all cinder blocks really lived up
to those specs, but of
course they do not. Some are incredibly brittle and
crumbly. They might
serve just fine in construction when the holes are
facing upwards, but on
their sides they would be risky, even when just
supporting the weight of a
kiln. None of this "evidence" accomplishes anything in
defending the case
of kiln foundation blocks on their sides. A few sheets
of cement board are
a minimal expense to cover the blocks facing upwards.
I am still waiting
for some sort of compelling evidence that placing the
blocks on their sides
sufficient advantage to make it worth the risk. I have
never seen any
advantage at all to having the blocks on their sides,
as long as the kiln
floor is built properly.
- Vince
Janet Moe on sat 19 apr 08
I have never seen any
advantage at all to having the blocks on their sides,
as long as the kiln
floor is built properly.
- Vince
This has been a timely discussion as we are getting
ready to build the gas kilns in our new studio soon.
My partner has fired gas kilns for 30 years and
believes in the idea of placing the cinder blocks on
their sides for the ventilation under the kiln. I have
only built one kiln which I never quite finished
before deciding to move. I had the cinder blocks
facing upwards with cement board on top being
convinced by previous discussions on clayart.
One thing my partner said is that it is nice to be
able to stick your toes in the block when loading the
kiln in order to get closer. I'm thinking it may be an
idea to just put a couple of blocks on their side in
the front for this purpose.
I would like to hear from people why they believe it
is necessary for the ventilation under the kiln.
My thoughts so far are that either way works. The
stories of explosions all seem to be when the kiln is
built directly on the concrete pad with no cinder
blocks.
Janet, on Vancouver Island
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Vince Pitelka on sat 19 apr 08
Edouard wrote:
"I heard of a girl in Quebec who build a casted concrete
base with steel rods over a concrete floor.
At the first firing the base exploded probably because
of moisture remaining in the base.
Everything was kaput..."
Edouard -
As I understand it, in volumetric concrete castings, the moisture is in
there permanently. The concrete doesn't really dry out, and subjecting it
to intense heat is always a very dangerous proposition. When I worked as a
mechanic and welder, if I was cutting steel with a torch, and the spatter
was falling in a concentrated area on the concrete floor, it would start to
pop and spot, and that was indoors on the surface of a slab that had been
cast fifteen years before that.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Vince Pitelka on sat 19 apr 08
David Woof wrote:
"Cinder blocks are composed of cinders, either ground up industrial coal
fired clinker waste or mined from natural mountains of volcanic cinders.
These cinders are cemented together with enough concrete to give them a
ridged shape and meet certain and varied construction ratings. One can see
the cinder matrix.
True concrete blocks are an entirely different block, denser. harder,
thicker in internal dimensions, considerably stronger, and heavier in
actual weight than cinder block."
David -
I am sure that this is technically correct, but the reality is that many
people refer to all of them as cinder blocks. We have a concrete company
that makes what they call "cinder blocks" from Portland cement and coarse
sand. No cinders. There is barely enough Portland cement in the mix to
bind the sand particles, and the resulting blocks are very brittle. Every
time I see pallets of these blocks delivered to a local construction site,
there are always a few broken ones in each pallet, just from the shock
experienced in delivery. It doesn't instill much faith in the strength of
the blocks.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Vince Pitelka on sat 19 apr 08
Michael Wendt wrote:
"In order to be sold for construction,
blocks have to meet minimum codes.
The Uniform Building Code book I have
(Table 24-4) lists the minimum design load
at 150 PSI. Typical manufacturing wants to
exceed that value by a margin to avoid
liability issues."
Michael -
That is true, but as I understand it, the blocks are tested in the position
in which they will be used - with the holes facing upwards. No one tests
them laying on their sides. So they only have to meet specs when they are
standing with the holes facing upwards, which is how they are always used in
the building trades.
And regarding heat buildup, it is a non-issue if the floor is built
properly. Regardless of how you build your foundation, you do not want
excessive heat to accumulate beneath the refractory floor. If the floor
thickness was inadequate and enough heat soaked through to make the surface
of the concrete block pop, it would still happen if the block was on its
side. With the holes facing upwards and a sheet of cement board on top, any
heat that comes through the floor will dissipate much more easily into the
spaces in the blocks, and there is no chance at all that heat would
accumulate in those spaces to the point where the concrete would explode.
It takes direct contact with extreme heat for that to happen.
So as you can see, there is almost no chance of a concrete explosion if the
blocks are laid with the holes face-up, and there is a risk if they are laid
on their sides. I know this is counter-intuitive, with those open passages
beneath the kiln with the blocks laid on their sides, but when you really
examine everything that is going on, laying the blocks with the holes face
up makes a stronger, safer foundation.
Again, whatever the testing standards and codes are, I have seen a lot of
brittle, poor-quality concrete block out there. Within my own personal
experience, I have seen this at major building supply places locally, in
Massachusetts, in Los Angeles, and in central Arizona, and in Washington
State, so this is a very widespread problem.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Steve Mills on sun 20 apr 08
As the majority of the kilns I've built have been outside, I've always use hollow Cement blocks on their sides. More than anything to prevent damp from wicking up into the Kiln, but also to prevent the foundations from being a heat sink.
As my wood-fire Kilns have all the primary air coming in through the floor, an interface to prevent heat damage is not needed. Otherwise I use a layer of IFBs for that. Another way would be to use Engineering bricks for the base. In the UK these come with three large holes through each brick. They are strong, fired fairly high, and would allow the passage of air through them. I will be using them in my next indoor kiln.
The firebox floor in my woodfire kilns is always made out of perforated red house bricks, and they cope with that extremely well - no failures! so an engineering red brick support floor should also be problem free.
Steve
Bath
UK
Janet Moe wrote:
This has been a timely discussion as we are getting
ready to build the gas kilns in our new studio soon.
My partner has fired gas kilns for 30 years and
believes in the idea of placing the cinder blocks on
their sides for the ventilation under the kiln. I have
only built one kiln which I never quite finished
before deciding to move. I had the cinder blocks
facing upwards with cement board on top being
convinced by previous discussions on clayart.
One thing my partner said is that it is nice to be
able to stick your toes in the block when loading the
kiln in order to get closer. I'm thinking it may be an
idea to just put a couple of blocks on their side in
the front for this purpose.
I would like to hear from people why they believe it
is necessary for the ventilation under the kiln.
My thoughts so far are that either way works. The
stories of explosions all seem to be when the kiln is
built directly on the concrete pad with no cinder
blocks.
Janet, on Vancouver Island
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---------------------------------
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Larry Kruzan on sun 20 apr 08
A kiln that measures six foot on a side, five foot tall (6'x 6'x 5') made
from IFB, has 9" walls that carry 3000 pounds The weight of the arch is
included). I am not counting the floor for these calculations. I know this
because of the shipping weights of my kiln bricks.
So, a 3000 pound load distributed along a 9" wall, 21.5' long (21.5x12=258
sq. inches) is 3000 pounds / 258 sq inch = 11.62 pounds per square inch.
A hard brick kiln would weight around 3 to 4 times as much - not much more
than 50 PSI.
If I stand on the side of a block, on my tippy toes there would be a contact
area of 8 inches. I weigh 250 pounds. 250/8=31.5 psi. I have little doubt
that the block will hold me in either direction without crumbling away.
How much does a piano weight at its point of contact with the Floor - much
more than our kilns is my guess, yet they are safely standing in many homes
with plywood under the carpet.
Give it a rest Vince.
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Vince Pitelka
Sent: Saturday, April 19, 2008 8:58 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: [CLAYART] kiln foundations
Michael Wendt wrote:
"In order to be sold for construction,
blocks have to meet minimum codes.
The Uniform Building Code book I have
(Table 24-4) lists the minimum design load
at 150 PSI. Typical manufacturing wants to
exceed that value by a margin to avoid
liability issues."
Michael -
That is true, but as I understand it, the blocks are tested in the position
in which they will be used - with the holes facing upwards. No one tests
them laying on their sides. So they only have to meet specs when they are
standing with the holes facing upwards, which is how they are always used in
the building trades.
And regarding heat buildup, it is a non-issue if the floor is built
properly. Regardless of how you build your foundation, you do not want
excessive heat to accumulate beneath the refractory floor. If the floor
thickness was inadequate and enough heat soaked through to make the surface
of the concrete block pop, it would still happen if the block was on its
side. With the holes facing upwards and a sheet of cement board on top, any
heat that comes through the floor will dissipate much more easily into the
spaces in the blocks, and there is no chance at all that heat would
accumulate in those spaces to the point where the concrete would explode.
It takes direct contact with extreme heat for that to happen.
So as you can see, there is almost no chance of a concrete explosion if the
blocks are laid with the holes face-up, and there is a risk if they are laid
on their sides. I know this is counter-intuitive, with those open passages
beneath the kiln with the blocks laid on their sides, but when you really
examine everything that is going on, laying the blocks with the holes face
up makes a stronger, safer foundation.
Again, whatever the testing standards and codes are, I have seen a lot of
brittle, poor-quality concrete block out there. Within my own personal
experience, I have seen this at major building supply places locally, in
Massachusetts, in Los Angeles, and in central Arizona, and in Washington
State, so this is a very widespread problem.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
____________________________________________________________________________
__
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots2@visi.com
Kim Overall on sun 20 apr 08
Classic Vince
Totally Classic
It was so funny and well said I
had my husband read it and he chuckled, too.
Kim in Houston
(taking in all these notes about kiln building)
larry on sun 20 apr 08
Having be en a masonry contractor for the past 39 years I am amused by the =
discussion here. To make this very simple since the block are 8x8x16 altern=
ate them so that one block is laid on its side and one block is laid the tr=
aditional way, make sure the corners are laid the traditional way, then if =
you are still concerned place a 3 inch x 3 inch angle steel around the outs=
ide of the kiln supporting the weight of the arch so it distributes the wei=
ght evenly. The key is even distribution of the weight, as the block laid h=
oles up or holes side to side does not really matter. Avoid rapid changes s=
uch as sharp blows to the block or extremely rapid temperature changes. Mod=
ern concrete block are quite strong. An alternate would be that you build a=
complete angle steel frame with cross supports then place cement board and=
elevate the entire kiln on critically placed concrete block. Then you will=
never have a moisture problem and will have a complete free flow of air. A=
lthough I am a masonry contractor now days the kilns I build are raised off=
the ground on steel frames so if for some reason they need to be moved the=
y can easily. Just my thoughts. =0D=0A=0D=0ALarry Andre=0D=0A=0D=0A--------=
--------------------------------=0D=0AFrom: "Larry Kruzan" MCAST.NET>=0D=0ASent: Sunday, April 20, 2008 9:04 AM=0D=0ATo: CLAYART@LSV.C=
ERAMICS.ORG=0D=0ASubject: Re: kiln foundations =0D=0A=0D=0AA kiln that meas=
ures six foot on a side, five foot tall (6'x 6'x 5') made=0D=0Afrom IFB, ha=
s 9" walls that carry 3000 pounds The weight of the arch is=0D=0Aincluded).=
I am not counting the floor for these calculations. I know this=0D=0Abeca=
use of the shipping weights of my kiln bricks.=0D=0A=0D=0ASo, a 3000 pound =
load distributed along a 9" wall, 21.5' long (21.5x12=3D258=0D=0Asq. inches=
) is 3000 pounds / 258 sq inch =3D 11.62 pounds per square inch.=0D=0A=0D=
=0AA hard brick kiln would weight around 3 to 4 times as much - not much mo=
re=0D=0Athan 50 PSI.=0D=0A=0D=0AIf I stand on the side of a block, on my ti=
ppy toes there would be a contact=0D=0Aarea of 8 inches. I weigh 250 pound=
s. 250/8=3D31.5 psi. I have little doubt=0D=0Athat the block will hold me =
in either direction without crumbling away.=0D=0A=0D=0AHow much does a pian=
o weight at its point of contact with the Floor - much=0D=0Amore than our k=
ilns is my guess, yet they are safely standing in many homes=0D=0Awith plyw=
ood under the carpet.=0D=0A=0D=0AGive it a rest Vince.=0D=0A=0D=0ALarry Kru=
zan=0D=0ALost Creek Pottery=0D=0Awww.lostcreekpottery.com=0D=0A=0D=0A-----O=
riginal Message-----=0D=0AFrom: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] O=
n Behalf Of Vince Pitelka=0D=0ASent: Saturday, April 19, 2008 8:58 PM=0D=0A=
To: CLAYART@LSV.CERAMICS.ORG=0D=0ASubject: Re: [CLAYART] kiln foundations=
=0D=0A=0D=0AMichael Wendt wrote:=0D=0A"In order to be sold for construction=
,=0D=0Ablocks have to meet minimum codes.=0D=0AThe Uniform Building Code bo=
ok I have=0D=0A(Table 24-4) lists the minimum design load=0D=0Aat 150 PSI. =
Typical manufacturing wants to=0D=0Aexceed that value by a margin to avoid=
=0D=0Aliability issues."=0D=0A=0D=0AMichael -=0D=0AThat is true, but as I u=
nderstand it, the blocks are tested in the position=0D=0Ain which they will=
be used - with the holes facing upwards. No one tests=0D=0Athem laying on=
their sides. So they only have to meet specs when they are=0D=0Astanding w=
ith the holes facing upwards, which is how they are always used in=0D=0Athe=
building trades.=0D=0A=0D=0AAnd regarding heat buildup, it is a non-issue =
if the floor is built=0D=0Aproperly. Regardless of how you build your foun=
dation, you do not want=0D=0Aexcessive heat to accumulate beneath the refra=
ctory floor. If the floor=0D=0Athickness was inadequate and enough heat so=
aked through to make the surface=0D=0Aof the concrete block pop, it would s=
till happen if the block was on its=0D=0Aside. With the holes facing upward=
s and a sheet of cement board on top, any=0D=0Aheat that comes through the =
floor will dissipate much more easily into the=0D=0Aspaces in the blocks, a=
nd there is no chance at all that heat would=0D=0Aaccumulate in those space=
s to the point where the concrete would explode.=0D=0AIt takes direct conta=
ct with extreme heat for that to happen.=0D=0A=0D=0ASo as you can see, ther=
e is almost no chance of a concrete explosion if the=0D=0Ablocks are laid w=
ith the holes face-up, and there is a risk if they are laid=0D=0Aon their s=
ides. I know this is counter-intuitive, with those open passages=0D=0Abene=
ath the kiln with the blocks laid on their sides, but when you really=0D=0A=
examine everything that is going on, laying the blocks with the holes face=
=0D=0Aup makes a stronger, safer foundation.=0D=0A=0D=0AAgain, whatever the=
testing standards and codes are, I have seen a lot of=0D=0Abrittle, poor-q=
uality concrete block out there. Within my own personal=0D=0Aexperience, I=
have seen this at major building supply places locally, in=0D=0AMassachuse=
tts, in Los Angeles, and in central Arizona, and in Washington=0D=0AState, =
so this is a very widespread problem.=0D=0A- Vince=0D=0A=0D=0AVince Pitelka=
=0D=0AAppalachian Center for Craft=0D=0ATennessee Tech University=0D=0Avpit=
elka@dtccom.net; wpitelka@tntech.edu=0D=0Ahttp://iweb.tntech.edu/wpitelka=
=0D=0A=0D=0A_______________________________________________________________=
_____________=0D=0A__=0D=0AClayart members may send postings to: clayart@=
lsv.ceramics.org=0D=0A=0D=0AYou may look at the archives for the list, post=
messages, change your=0D=0Asubscription settings or unsubscribe/leave the =
list here:=0D=0Ahttp://www.acers.org/cic/clayart/=0D=0A=0D=0AModerator of t=
he list is Mel Jacobson who may be reached at=0D=0Amelpots2@visi.com=0D=0A=
=0D=0A_____________________________________________________________________=
_________=0D=0AClayart members may send postings to: clayart@lsv.ceramics=
.org=0D=0A=0D=0AYou may look at the archives for the list, post messages, c=
hange your=0D=0Asubscription settings or unsubscribe/leave the list here: =
http://www.acers.org/cic/clayart/=0D=0A=0D=0AModerator of the list is Mel J=
acobson who may be reached at melpots2@visi.com=0D=0A=0D=0A
jonathan byler on mon 21 apr 08
I think that you could spec from a local block manufacturer what mix
they should use. they may also not be curing the blocks properly.
all cement products, when cured properly increase in strength over
time. Takes about 28 days to reach so called "maximum strength", but
they keep getting stronger the longer you wait. Those blocks may
have been from a poor mix, or they may have just dried too fast.
hard to say. regardless, buying materials from a reputable supplier,
even if it costs a bit more shows much better economy than to buy
from the guys who do a hack job of it. tearing down your kiln (or
house) to fix a crappy foundation is a pricey way to go about saving
a few bucks up front.
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 19, 2008, at 7:50 PM, Vince Pitelka wrote:
> David Woof wrote:
> "Cinder blocks are composed of cinders, either ground up industrial
> coal
> fired clinker waste or mined from natural mountains of volcanic
> cinders.
> These cinders are cemented together with enough concrete to give
> them a
> ridged shape and meet certain and varied construction ratings. One
> can see
> the cinder matrix.
> True concrete blocks are an entirely different block, denser. harder,
> thicker in internal dimensions, considerably stronger, and heavier in
> actual weight than cinder block."
>
> David -
> I am sure that this is technically correct, but the reality is that
> many
> people refer to all of them as cinder blocks. We have a concrete
> company
> that makes what they call "cinder blocks" from Portland cement and
> coarse
> sand. No cinders. There is barely enough Portland cement in the
> mix to
> bind the sand particles, and the resulting blocks are very brittle.
> Every
> time I see pallets of these blocks delivered to a local
> construction site,
> there are always a few broken ones in each pallet, just from the shock
> experienced in delivery. It doesn't instill much faith in the
> strength of
> the blocks.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net; wpitelka@tntech.edu
> http://iweb.tntech.edu/wpitelka
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://
> www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
jonathan byler on mon 21 apr 08
well, concrete blocks, and concrete backer board are all made of
concrete/cement of some sort, and as such all contain chemical water,
so no matter on their sides or straight up and down, you still have
to build a decent floor as vince stated. Putting the expanded metal
down seems like a good idea, but again, I'm not sure if you built the
floor right, if you would even need that. I am getting tempted to
weld up a serious steel frame, but some bureaucrats have just decided
to take a huge bite out of our budget...
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 19, 2008, at 4:22 PM, Janet Moe wrote:
> I have never seen any
> advantage at all to having the blocks on their sides,
> as long as the kiln
> floor is built properly.
> - Vince
>
> This has been a timely discussion as we are getting
> ready to build the gas kilns in our new studio soon.
> My partner has fired gas kilns for 30 years and
> believes in the idea of placing the cinder blocks on
> their sides for the ventilation under the kiln. I have
> only built one kiln which I never quite finished
> before deciding to move. I had the cinder blocks
> facing upwards with cement board on top being
> convinced by previous discussions on clayart.
>
> One thing my partner said is that it is nice to be
> able to stick your toes in the block when loading the
> kiln in order to get closer. I'm thinking it may be an
> idea to just put a couple of blocks on their side in
> the front for this purpose.
>
> I would like to hear from people why they believe it
> is necessary for the ventilation under the kiln.
>
> My thoughts so far are that either way works. The
> stories of explosions all seem to be when the kiln is
> built directly on the concrete pad with no cinder
> blocks.
>
> Janet, on Vancouver Island
>
>
>
> __________________________________________________________________
> Looking for the perfect gift? Give the gift of Flickr!
>
> http://www.flickr.com/gift/
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://
> www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
Clayart SCtag on mon 21 apr 08
Yes, to the quality of the blocks as our supplier sells block for
construction and discounted block which do not meet those specks as gardening
blocks that will not be in a structure..
Meg
In a message dated 4/21/2008 3:47:48 P.M. Eastern Daylight Time,
jebyler2@GMAIL.COM writes:
I think that you could spec from a local block manufacturer what mix
they should use. they may also not be curing the blocks properly.
all cement products, when cured properly increase in strength over
time. Takes about 28 days to reach so called "maximum strength", but
they keep getting stronger the longer you wait. Those blocks may
have been from a poor mix, or they may have just dried too fast.
hard to say. regardless, buying materials from a reputable supplier,
even if it costs a bit more shows much better economy than to buy
from the guys who do a hack job of it. tearing down your kiln (or
house) to fix a crappy foundation is a pricey way to go about saving
a few bucks up front.
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 19, 2008, at 7:50 PM, Vince Pitelka wrote:
> David Woof wrote:
> "Cinder blocks are composed of cinders, either ground up industrial
> coal
> fired clinker waste or mined from natural mountains of volcanic
> cinders.
> These cinders are cemented together with enough concrete to give
> them a
> ridged shape and meet certain and varied construction ratings. One
> can see
> the cinder matrix.
> True concrete blocks are an entirely different block, denser. harder,
> thicker in internal dimensions, considerably stronger, and heavier in
> actual weight than cinder block."
>
> David -
> I am sure that this is technically correct, but the reality is that
> many
> people refer to all of them as cinder blocks. We have a concrete
> company
> that makes what they call "cinder blocks" from Portland cement and
> coarse
> sand. No cinders. There is barely enough Portland cement in the
> mix to
> bind the sand particles, and the resulting blocks are very brittle.
> Every
> time I see pallets of these blocks delivered to a local
> construction site,
> there are always a few broken ones in each pallet, just from the shock
> experienced in delivery. It doesn't instill much faith in the
> strength of
> the blocks.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net; wpitelka@tntech.edu
> http://iweb.tntech.edu/wpitelka
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://
> www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
______________________________________________________________________________
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots2@visi.com
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
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Hank Murrow on mon 21 apr 08
On Apr 21, 2008, at 10:40 AM, jonathan byler wrote:
> well, concrete blocks, and concrete backer board are all made of
> concrete/cement of some sort, and as such all contain chemical water,
> so no matter on their sides or straight up and down, you still have
> to build a decent floor as vince stated. Putting the expanded metal
> down seems like a good idea, but again, I'm not sure if you built the
> floor right, if you would even need that. I am getting tempted to
> weld up a serious steel frame, but some bureaucrats have just decided
> to take a huge bite out of our budget...
Dear Jon;
If there is an auto or aircraft repair program at Auburn or a nearby
Community College, you might be able to get the welding/fabricating
done for free if you pay for materials.
Cheers, Hank in Eugene.
Duff bogen on mon 21 apr 08
Cement blocks in their normal orientation are 7.5" matching 3 bricks at 2.5"
a nice match for laying out a design
DRB
Seattle
jonathan byler wrote:
well, concrete blocks, and concrete backer board are all made of
concrete/cement of some sort, and as such all contain chemical water,
so no matter on their sides or straight up and down, you still have
to build a decent floor as vince stated. Putting the expanded metal
down seems like a good idea, but again, I'm not sure if you built the
floor right, if you would even need that. I am getting tempted to
weld up a serious steel frame, but some bureaucrats have just decided
to take a huge bite out of our budget...
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 19, 2008, at 4:22 PM, Janet Moe wrote:
> I have never seen any
> advantage at all to having the blocks on their sides,
> as long as the kiln
> floor is built properly.
> - Vince
>
> This has been a timely discussion as we are getting
> ready to build the gas kilns in our new studio soon.
> My partner has fired gas kilns for 30 years and
> believes in the idea of placing the cinder blocks on
> their sides for the ventilation under the kiln. I have
> only built one kiln which I never quite finished
> before deciding to move. I had the cinder blocks
> facing upwards with cement board on top being
> convinced by previous discussions on clayart.
>
> One thing my partner said is that it is nice to be
> able to stick your toes in the block when loading the
> kiln in order to get closer. I'm thinking it may be an
> idea to just put a couple of blocks on their side in
> the front for this purpose.
>
> I would like to hear from people why they believe it
> is necessary for the ventilation under the kiln.
>
> My thoughts so far are that either way works. The
> stories of explosions all seem to be when the kiln is
> built directly on the concrete pad with no cinder
> blocks.
>
> Janet, on Vancouver Island
>
>
>
> __________________________________________________________________
> Looking for the perfect gift? Give the gift of Flickr!
>
> http://www.flickr.com/gift/
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://
> www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
______________________________________________________________________________
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here: http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.com
---------------------------------
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jonathan byler on mon 21 apr 08
fortunately, In addition to overseeing the ceramics studios, I also
run the sculpture shop here. Welding is no problem. What is a
problem is the current price of steel! I am still thinking about
making the base out of structural steel tubing and angle iron. All
depends on the budget, which got eaten up by the $10,000 hole in the
roof. If I wouldn't get fired for doing it, I would climb up there
and put in the chimney myself!
jon
jon byler
3-D Building Coordinator
Art Department
Auburn University, AL 36849
On Apr 21, 2008, at 4:10 PM, Hank Murrow wrote:
> On Apr 21, 2008, at 10:40 AM, jonathan byler wrote:
>
>> well, concrete blocks, and concrete backer board are all made of
>> concrete/cement of some sort, and as such all contain chemical water,
>> so no matter on their sides or straight up and down, you still have
>> to build a decent floor as vince stated. Putting the expanded metal
>> down seems like a good idea, but again, I'm not sure if you built the
>> floor right, if you would even need that. I am getting tempted to
>> weld up a serious steel frame, but some bureaucrats have just decided
>> to take a huge bite out of our budget...
>
> Dear Jon;
>
> If there is an auto or aircraft repair program at Auburn or a nearby
> Community College, you might be able to get the welding/fabricating
> done for free if you pay for materials.
>
> Cheers, Hank in Eugene.
>
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://
> www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
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