gary navarre on wed 4 apr 12
Vince's caution and suggestion is an adequate alternative to w=3D
Jon,=3D0A=3D0A=3DA0Vince's caution and suggestion is an adequate alternativ=
e to w=3D
hat I tried once and proved to myself didn't work too good. Here is a littl=
=3D
e bit of what I shot as best I could of what happened to the cement block I=
=3D
used as fill behind firebrick & blanket as part of the floor ...=3D0A=3D0A=
http=3D
://public.fotki.com/GindaUP/ca/kpap/kbhd/ =3D0A=3D0A=3D0AOne was behind 9" =
of sol=3D
id refractory foundry block and it became a wreck after 4-5 firings so I di=
=3D
dn't use any in the rebuild up here. I built on top of stone and gravel and=
=3D
the floor is 4.5" hard brick on edge. If I rebuild again I'd set a layer f=
=3D
lat so the floor would be about 7" thick and/or IFB if I had some extra.=3D=
A0=3D
=3D0A=3D0A=3DA0I'm curious how you will hook up a Bourry box.=3D0A=3D0A=3DA=
0=3D0AGary Nav=3D
arre=3D0ANavarre Pottery=3D0ANavarre Enterprises=3D0ANorway, Michigan, USA=
=3D0Ahttp=3D
://www.NavarrePottery.etsy.com=3DA0=3DA0=3DA0=3DA0=3DA0 <...... New Pots=3D=
0Ahttp://www=3D
.youtube.com/GindaUP=3D0Ahttp://public.fotki.com/GindaUP/=3D0A=3D0A=3D0A=3D=
0A________=3D
________________________=3D0A From: jonathan byler =3D0=
ATo:=3D
Clayart@LSV.CERAMICS.ORG =3D0ASent: Wednesday, April 4, 2012 8:47 PM=3D0AS=
ubje=3D
ct: [Clayart] wood kiln progress.=3D0A =3D0AI have finally gotten half of t=
he f=3D
oundation laid for our wood kiln.=3D0ABefore I proceed to the next stage of=
a=3D
ctually laying the floor, I=3D0Ahave a quick question for the more experien=
ce=3D
d out there.=3DA0 I plan to=3D0Abuild a kiln similar to Lee Love's and Euan=
cra=3D
ig's, where the firebox=3D0Agoes under the floor.=3DA0 unlike theirs, howev=
er, =3D
I will be putting a=3D0Abourrey box on the front and moving the door to the=
s=3D
ide.=3DA0 since there=3D0Awill be little or no cool secondary air coming in=
to t=3D
he space under=3D0Athe kiln floor, and I am planning to try to preheat all =
co=3D
mbustion air=3D0Aby building a heat exchanger in the chimney, I am concerne=
d =3D
about the=3D0Apossible heat buildup between the firebox floor and the cemen=
t =3D
block=3D0Athat forms the foundation.=3D0A=3D0AI have 4" tall x 8" x=3DA0 16=
" cement=3D
blocks running under the floor, and=3D0Awill put a layer of durock board o=
n =3D
top of this to give me as level a=3D0Abuilding surface as possible.=3DA0 I =
was =3D
wondering if two layers of=3D0Ahardbrick will be adequate if I stagger the =
jo=3D
ints so as not to leave=3D0Aany direct paths for heat to radiate through to=
t=3D
he concrete block, or=3D0Awhether I should put something else there, such a=
s =3D
a layer or two of=3D0Ainsulating castable refractory or a layer or two of s=
of=3D
t bricks.=3DA0 I am=3D0Atrying to conserve soft bricks since I have those i=
n so=3D
mewhat limited=3D0Asupply, but a relatively large source of hard firebricks=
.=3D
=3DA0 from there=3D0Aon up I don't foresee any issues, but I am concerned a=
bout=3D
2000+=3D0Adegree temperatures in the channels under the floor blowing up t=
he=3D
=3D0Aconcrete block or worse the pad underneath.=3D0A=3D0AAny thoughts or a=
dvice =3D
would be welcome.=3D0A=3D0Athanks,=3D0Ajon
jonathan byler on wed 4 apr 12
I have finally gotten half of the foundation laid for our wood kiln.
Before I proceed to the next stage of actually laying the floor, I
have a quick question for the more experienced out there. I plan to
build a kiln similar to Lee Love's and Euan craig's, where the firebox
goes under the floor. unlike theirs, however, I will be putting a
bourrey box on the front and moving the door to the side. since there
will be little or no cool secondary air coming into the space under
the kiln floor, and I am planning to try to preheat all combustion air
by building a heat exchanger in the chimney, I am concerned about the
possible heat buildup between the firebox floor and the cement block
that forms the foundation.
I have 4" tall x 8" x 16" cement blocks running under the floor, and
will put a layer of durock board on top of this to give me as level a
building surface as possible. I was wondering if two layers of
hardbrick will be adequate if I stagger the joints so as not to leave
any direct paths for heat to radiate through to the concrete block, or
whether I should put something else there, such as a layer or two of
insulating castable refractory or a layer or two of soft bricks. I am
trying to conserve soft bricks since I have those in somewhat limited
supply, but a relatively large source of hard firebricks. from there
on up I don't foresee any issues, but I am concerned about 2000+
degree temperatures in the channels under the floor blowing up the
concrete block or worse the pad underneath.
Any thoughts or advice would be welcome.
thanks,
jon
Vince Pitelka on wed 4 apr 12
Jonathan Byler wrote:
I have 4" tall x 8" x 16" cement blocks running under the floor, and will
put a layer of durock board on top of this to give me as level a building
surface as possible. I was wondering if two layers of hardbrick will be
adequate if I stagger the joints so as not to leave any direct paths for
heat to radiate through to the concrete block, or whether I should put
something else there, such as a layer or two of insulating castable
refractory or a layer or two of soft bricks. I am trying to conserve soft
bricks since I have those in somewhat limited supply, but a relatively larg=
e
source of hard firebricks. from there on up I don't foresee any issues, bu=
t
I am concerned about 2000+ degree temperatures in the channels under the
floor blowing up the concrete block or worse the pad underneath. Any
thoughts or advice would be welcome."
Hi Jon. Sorry for the way this sounds, but this is not the time to skimp o=
n
brick. Put down a layer of softbrick, and then two layers of hardbrick. N=
o
less than three layers of brick in the floor. Three layers of hardbrick
would probably be satisfactory, but two layers of hardbrick on top of one
layer of softbrick would be much better. Remember that two layers of
hardbrick is only 5" thick, and that isn't much insulation. Back when I wa=
s
in undergraduate school at Humboldt State a guy I knew built a salt kiln on
a concrete slab with two layers of hardbrick in the floor. Just after he
finished salting the slab exploded. Fortunately everyone was well back fro=
m
the kiln and no one was injured or worse, but all the pots and shelves were
a total loss and the bricks all had to be broken apart. I really learned a
valuable lesson there. Keep heat away from concrete, including cement boar=
d
and concrete block. They won't explode the way solid cast concrete can, bu=
t
they will lose their structural integrity if exposed to too much heat.
Don't take any chances.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/
Steve Mills on thu 5 apr 12
Jonathan,=3D20
In the kiln we built in SC with our friend Ruth Ballou (double Bourry down =
d=3D
raft), the base "sandwich" is (in order) concrete pad, membrane, hollow con=
c=3D
rete blocks, reclaimed IFBs, hard-brick tiles.=3D20
The hollow blocks is something I always do, as it helps disperse moisture w=
i=3D
cking upwards, and cool air flowing through them is also helpful in retaini=
n=3D
g the integrity of the base.=3D20
The addition of the membrane was perhaps a bit " belt and braces (suspender=
s=3D
to you)" and with hindsight possibly uneccessary, but it's there for 'a' t=
h=3D
at.=3D20
Steve M.=3D20
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 5 Apr 2012, at 03:47, jonathan byler wrote:
> I have finally gotten half of the foundation laid for our wood kiln.
> Before I proceed to the next stage of actually laying the floor, I
> have a quick question for the more experienced out there. I plan to
> build a kiln similar to Lee Love's and Euan craig's, where the firebox
> goes under the floor. unlike theirs, however, I will be putting a
> bourrey box on the front and moving the door to the side. since there
> will be little or no cool secondary air coming into the space under
> the kiln floor, and I am planning to try to preheat all combustion air
> by building a heat exchanger in the chimney, I am concerned about the
> possible heat buildup between the firebox floor and the cement block
> that forms the foundation.
>=3D20
> I have 4" tall x 8" x 16" cement blocks running under the floor, and
> will put a layer of durock board on top of this to give me as level a
> building surface as possible. I was wondering if two layers of
> hardbrick will be adequate if I stagger the joints so as not to leave
> any direct paths for heat to radiate through to the concrete block, or
> whether I should put something else there, such as a layer or two of
> insulating castable refractory or a layer or two of soft bricks. I am
> trying to conserve soft bricks since I have those in somewhat limited
> supply, but a relatively large source of hard firebricks. from there
> on up I don't foresee any issues, but I am concerned about 2000+
> degree temperatures in the channels under the floor blowing up the
> concrete block or worse the pad underneath.
>=3D20
> Any thoughts or advice would be welcome.
>=3D20
> thanks,
> jon
Steve Mills on thu 5 apr 12
Vince=3D20
I completely agree with you about the neccesity of IFBs and avoidance of ce=
m=3D
ent board, but I've never had a problem with concrete blocks in that situat=
i=3D
on, though I have to say I use hollow ones where possible. =3D20
I have several kilns still working hard and well after a fair number of yea=
r=3D
s that sit on them, and three that are on solid blocks.=3D20
With Ruth's kiln in SC the hollow blocks used are identical to those availa=
b=3D
le in the UK.=3D20
Glad to hear you are walking straight and true again.=3D20
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 5 Apr 2012, at 04:32, Vince Pitelka wrote:
> Keep heat away from concrete, including cement board
> and concrete block. They won't explode the way solid cast concrete can, =
b=3D
ut
> they will lose their structural integrity if exposed to too much heat.
> Don't take any chances.
> - Vince
>=3D20
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net
> http://iweb.tntech.edu/wpitelka/
wileyhill@COMCAST.NET on thu 5 apr 12
I have experience in building exactly one kiln, so take this from whence it=
came, but I agree with Vince. In addition to the concrete issue, a friend =
relayed stories of firing kilns without insulating brick in the floor that =
were a serious PITA to get to temp as the ground is a great heat sink. Ever=
camped on the ground without enough stuff under you in the fall? Brrr!
If all of your firebox is under the floor, as in an Olsen fastfire design- =
the kiln should fire quickly and with less fuel, but I would expect much le=
ss ash-and-flash woodfire effects. I fire a Bourry box design venting right=
into the chamber without even a step and I get great results especially up=
front.
Where do you live? If you are close, then I have enough broken/spare softbr=
ick that you can have that would probably form a full base for you for the =
cost of gas to come get them. (I'm in S.NH)
Paul Haigh
Wiley Hill Mudworks
Web: http://wileyhill.com
Facebook: http://www.facebook.com/pages/Wiley-Hill-Mudworks/108145139230652
etsy: http://www.etsy.com/shop/WileyHillMudworks
Roland Beevor on thu 5 apr 12
Gary
Thanks for posting those pictures, very interesting.
Was this kiln only used a few times? I wonder whether
the concrete would have fared better with more
insulating material rather than fire brick, which would
absorb a lot of heat?
Cheers
Roly
On 05/04/2012 06:22, gary navarre wrote:
> Vince's caution and suggestion is an adequate alternative to w
> Jon,
>
> Vince's caution and suggestion is an adequate alternative to what I tri=
ed once and proved to myself didn't work too good. Here is a little bit of =
what I shot as best I could of what happened to the cement block I used as =
fill behind firebrick& blanket as part of the floor ...
>
> http://public.fotki.com/GindaUP/ca/kpap/kbhd/
>
>
> One was behind 9" of solid refractory foundry block and it became a wreck=
after 4-5 firings so I didn't use any in the rebuild up here. I built on t=
op of stone and gravel and the floor is 4.5" hard brick on edge. If I rebui=
ld again I'd set a layer flat so the floor would be about 7" thick and/or I=
FB if I had some extra.
>
> I'm curious how you will hook up a Bourry box.
>
>
> Gary Navarre
> Navarre Pottery
> Navarre Enterprises
> Norway, Michigan, USA
> http://www.NavarrePottery.etsy.com<...... New Pots
> http://www.youtube.com/GindaUP
> http://public.fotki.com/GindaUP/
>
>
>
> ________________________________
> From: jonathan byler
> To: Clayart@LSV.CERAMICS.ORG
> Sent: Wednesday, April 4, 2012 8:47 PM
> Subject: [Clayart] wood kiln progress.
>
> I have finally gotten half of the foundation laid for our wood kiln.
> Before I proceed to the next stage of actually laying the floor, I
> have a quick question for the more experienced out there. I plan to
> build a kiln similar to Lee Love's and Euan craig's, where the firebox
> goes under the floor. unlike theirs, however, I will be putting a
> bourrey box on the front and moving the door to the side. since there
> will be little or no cool secondary air coming into the space under
> the kiln floor, and I am planning to try to preheat all combustion air
> by building a heat exchanger in the chimney, I am concerned about the
> possible heat buildup between the firebox floor and the cement block
> that forms the foundation.
>
> I have 4" tall x 8" x 16" cement blocks running under the floor, and
> will put a layer of durock board on top of this to give me as level a
> building surface as possible. I was wondering if two layers of
> hardbrick will be adequate if I stagger the joints so as not to leave
> any direct paths for heat to radiate through to the concrete block, or
> whether I should put something else there, such as a layer or two of
> insulating castable refractory or a layer or two of soft bricks. I am
> trying to conserve soft bricks since I have those in somewhat limited
> supply, but a relatively large source of hard firebricks. from there
> on up I don't foresee any issues, but I am concerned about 2000+
> degree temperatures in the channels under the floor blowing up the
> concrete block or worse the pad underneath.
>
> Any thoughts or advice would be welcome.
>
> thanks,
> jon
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.1913 / Virus Database: 2409/4915 - Release Date: 04/04/12
>
>
>
gary navarre on thu 5 apr 12
I don't know Roland, I decided to invest my time and money in a 4.5" firebr=
=3D
ick floor with a layer of clay on top of gravel with stones underneath for =
=3D
drainage and to prevent kiln damp. The kiln down below was only fired about=
=3D
4-5 times and that is how much damage occurred so I'd insulate the hell ou=
=3D
t of the floor if you want the kiln up off the ground for easier loading. I=
=3D
wear construction knee pads to load so my knees don't take such a beating =
=3D
as when I was a kid in my late '40's.=3D0A=3D0A=3DA0=3D0AGary Navarre=3D0AN=
avarre Pot=3D
tery=3D0ANavarre Enterprises=3D0ANorway, Michigan, USA=3D0Ahttp://www.Navar=
rePott=3D
ery.etsy.com=3DA0=3DA0=3DA0=3DA0=3DA0 <...... New Pots=3D0Ahttp://www.youtu=
be.com/Ginda=3D
UP=3D0Ahttp://public.fotki.com/GindaUP/=3D0A=3D0A=3D0A=3D0A________________=
__________=3D
______=3D0A From: Roland Beevor =3D0ATo: gary na=
varr=3D
e =3D0ACc: Clayart@LSV.CERAMICS.ORG =3D0ASen=
t: T=3D
hursday, April 5, 2012 8:46 AM=3D0ASubject: Re: [Clayart] wood kiln progres=
s.=3D
=3D0A =3D0AGary=3D0A=3D0AThanks for posting those pictures, very interestin=
g.=3DA0 =3D
=3D0AWas this kiln only used a few times?=3DA0 I wonder whether =3D0Athe co=
ncrete=3D
would have fared better with more =3D0Ainsulating material rather than fir=
e =3D
brick, which would =3D0Aabsorb a lot of heat?=3D0A=3D0ACheers=3D0ARoly=3D0A=
=3D0A=3D0AOn 0=3D
5/04/2012 06:22, gary navarre wrote:=3D0A>=3DA0 Vince's caution and sugges=
tion=3D
is an adequate alternative to w=3D0A> Jon,=3D0A>=3D0A>=3DA0 Vince's cauti=
on and s=3D
uggestion is an adequate alternative to what I tried once and proved to mys=
=3D
elf didn't work too good. Here is a little bit of what I shot as best I cou=
=3D
ld of what happened to the cement block I used as fill behind firebrick&=3D=
A0=3D
blanket as part of the floor ...=3D0A>=3D0A> http://public.fotki.com/Ginda=
UP/c=3D
a/kpap/kbhd/=3D0A>=3D0A>=3D0A> One was behind 9" of solid refractory foundr=
y bloc=3D
k and it became a wreck after 4-5 firings so I didn't use any in the rebuil=
=3D
d up here. I built on top of stone and gravel and the floor is 4.5" hard br=
=3D
ick on edge. If I rebuild again I'd set a layer flat so the floor would be =
=3D
about 7" thick and/or IFB if I had some extra. =3D0A>=3D0A>=3DA0 I'm curio=
us how=3D
you will hook up a Bourry box.=3D0A>=3D0A>=3DA0 =3D0A> Gary Navarre=3D0A> =
Navarre Po=3D
ttery=3D0A> Navarre Enterprises=3D0A> Norway, Michigan, USA=3D0A> http://ww=
w.Nava=3D
rrePottery.etsy.com<...... New Pots=3D0A> http://www.youtube.com/GindaUP=3D=
0A> =3D
http://public.fotki.com/GindaUP/=3D0A>=3D0A>=3D0A>=3D0A> __________________=
________=3D
______=3D0A>=3DA0 From: jonathan byler=3D0A> To: Claya=
rt@LSV=3D
.CERAMICS.ORG=3D0A> Sent: Wednesday, April 4, 2012 8:47 PM=3D0A> Subject: [=
Clay=3D
art] wood kiln progress.=3D0A>=3D0A> I have finally gotten half of the foun=
dati=3D
on laid for our wood kiln.=3D0A> Before I proceed to the next stage of actu=
al=3D
ly laying the floor, I=3D0A> have a quick question for the more experienced=
o=3D
ut there.=3DA0 I plan to=3D0A> build a kiln similar to Lee Love's and Euan =
crai=3D
g's, where the firebox=3D0A> goes under the floor.=3DA0 unlike theirs, howe=
ver,=3D
I will be putting a=3D0A> bourrey box on the front and moving the door to =
th=3D
e side.=3DA0 since there=3D0A> will be little or no cool secondary air comi=
ng i=3D
nto the space under=3D0A> the kiln floor, and I am planning to try to prehe=
at=3D
all combustion air=3D0A> by building a heat exchanger in the chimney, I am=
c=3D
oncerned about the=3D0A> possible heat buildup between the firebox floor an=
d =3D
the cement block=3D0A> that forms the foundation.=3D0A>=3D0A> I have 4" tal=
l x 8"=3D
x=3DA0 16" cement blocks running under the floor, and=3D0A> will put a lay=
er o=3D
f durock board on top of this to give me as level a=3D0A> building surface =
as=3D
possible.=3DA0 I was wondering if two layers of=3D0A> hardbrick will be ad=
equa=3D
te if I stagger the joints so as not to leave=3D0A> any direct paths for he=
at=3D
to radiate through to the concrete block, or=3D0A> whether I should put so=
me=3D
thing else there, such as a layer or two of=3D0A> insulating castable refra=
ct=3D
ory or a layer or two of soft bricks.=3DA0 I am=3D0A> trying to conserve so=
ft b=3D
ricks since I have those in somewhat limited=3D0A> supply, but a relatively=
l=3D
arge source of hard firebricks.=3DA0 from there=3D0A> on up I don't foresee=
any=3D
issues, but I am concerned about 2000+=3D0A> degree temperatures in the ch=
an=3D
nels under the floor blowing up the=3D0A> concrete block or worse the pad u=
nd=3D
erneath.=3D0A>=3D0A> Any thoughts or advice would be welcome.=3D0A>=3D0A> t=
hanks,=3D
=3D0A> jon=3D0A>=3D0A>=3D0A>=3D0A> -----=3D0A> No virus found in this messa=
ge.=3D0A> Chec=3D
ked by AVG - www.avg.com=3D0A> Version: 2012.0.1913 / Virus Database: 2409/=
49=3D
15 - Release Date: 04/04/12=3D0A>=3D0A>=3D0A>
jonathan byler on thu 5 apr 12
my preheating scheme will do nothing at all to cool the air, since the
preheated air will hopefully be coming from waste heat in the stack if
all goes well.
concrete block on slab construction.
On Apr 4, 2012, at 9:49 PM, Hank Murrow wrote:
>
> On Apr 4, 2012, at 6:47 PM, jonathan byler wrote:
>
>> I have finally gotten half of the foundation laid for our wood kiln.
>
> Jonathan;
>
> Is your pad crushed rock or concrete?
>
> If concrete, there is a worry from excess heat. Also, concrete wicks
> moisture which causes excess fuel use.
>
> IF crushed rock there should be little worry in each case. And put a
> metal vapor barrier between any concrete and the brickwork.
>
>> I am concerned about 2000+
>> degree temperatures in the channels under the floor blowing up the
>> concrete block or worse the pad underneath.
>
> My guess is that the preheating will have the effect of cooling the
> floor as the incoming air is heated.
>
> Been there, and done most of it.
>
> Hank in Eugene
jonathan byler on thu 5 apr 12
what is this fiber board that you use? do you have a link to a
picture of a piece of this stuff? how much does it cost?
thanks,
jon
On Apr 4, 2012, at 10:37 PM, Bill Merrill wrote:
> Jonathon,
>
> In all the 50 or so kilns I have built, I never skimped on the
> floor. I use a fiber board on the concrete block, add a complete
> layer of insulators on their sides, so the brick are 4 1/2 ", then
> layer 2 rows of hard brick. This way no air will be sucked thru the
> floor and nothing can go wrong at the floor level. This is what I
> have done on wood and all the gas kilns I have built.
>
> I have fired wood kilns in Shigaraki and those kilns were well built
> on tamped hard pan earth and some had blocks under the floor, and
> were insulated from the top down. The kiln I fired in Shigaraki is
> owned by Shiho Kansaki. Many of those kilns have to refire pots as
> there are many cold spots in the upper part of the kiln. At the
> back of his kiln was a wall that the flues lead to a 30" chamber(the
> secret chamber) and then the gases exited thru the very back wall to
> the sloped chimney. It eventually was vertical b only about 4 feet
> tall, barily sticking from the ground. \Attached is my Flickr site
> which has pictures of my bourry box and other kilns I have built.
>
> Good luck with your endeavors and firings!!
>
> Bill
>
>
> http://www.flickr.com/photos/25594880@N04/ hweb/bin/redir.asp?URL=3Dhttp://www.flickr.com/photos/25594880@N04/
> >
>
>
> ________________________________
>
> From: Clayart on behalf of jonathan byler
> Sent: Wed 4/4/2012 6:47 PM
> To: Clayart@LSV.CERAMICS.ORG
> Subject: wood kiln progress.
>
>
>
> I have finally gotten half of the foundation laid for our wood kiln.
> Before I proceed to the next stage of actually laying the floor, I
> have a quick question for the more experienced out there. I plan to
> build a kiln similar to Lee Love's and Euan craig's, where the firebox
> goes under the floor. unlike theirs, however, I will be putting a
> bourrey box on the front and moving the door to the side. since there
> will be little or no cool secondary air coming into the space under
> the kiln floor, and I am planning to try to preheat all combustion air
> by building a heat exchanger in the chimney, I am concerned about the
> possible heat buildup between the firebox floor and the cement block
> that forms the foundation.
>
> I have 4" tall x 8" x 16" cement blocks running under the floor, and
> will put a layer of durock board on top of this to give me as level a
> building surface as possible. I was wondering if two layers of
> hardbrick will be adequate if I stagger the joints so as not to leave
> any direct paths for heat to radiate through to the concrete block, or
> whether I should put something else there, such as a layer or two of
> insulating castable refractory or a layer or two of soft bricks. I am
> trying to conserve soft bricks since I have those in somewhat limited
> supply, but a relatively large source of hard firebricks. from there
> on up I don't foresee any issues, but I am concerned about 2000+
> degree temperatures in the channels under the floor blowing up the
> concrete block or worse the pad underneath.
>
> Any thoughts or advice would be welcome.
>
> thanks,
> jon
>
>
>
jonathan byler on thu 5 apr 12
p.s. Thanks all for the advice. the base cement blocks to level the
slab are now half mortared in place, hopefully today I can be done
with that and move on to the rest of the construction.
On Apr 4, 2012, at 9:32 PM, Vince Pitelka wrote:
> Jonathan Byler wrote:
> I have 4" tall x 8" x 16" cement blocks running under the floor,
> and will
> put a layer of durock board on top of this to give me as level a
> building
> surface as possible. I was wondering if two layers of hardbrick
> will be
> adequate if I stagger the joints so as not to leave any direct paths
> for
> heat to radiate through to the concrete block, or whether I should put
> something else there, such as a layer or two of insulating castable
> refractory or a layer or two of soft bricks. I am trying to
> conserve soft
> bricks since I have those in somewhat limited supply, but a
> relatively large
> source of hard firebricks. from there on up I don't foresee any
> issues, but
> I am concerned about 2000+ degree temperatures in the channels under
> the
> floor blowing up the concrete block or worse the pad underneath. Any
> thoughts or advice would be welcome."
>
> Hi Jon. Sorry for the way this sounds, but this is not the time to
> skimp on
> brick. Put down a layer of softbrick, and then two layers of
> hardbrick. No
> less than three layers of brick in the floor. Three layers of
> hardbrick
> would probably be satisfactory, but two layers of hardbrick on top
> of one
> layer of softbrick would be much better. Remember that two layers of
> hardbrick is only 5" thick, and that isn't much insulation. Back
> when I was
> in undergraduate school at Humboldt State a guy I knew built a salt
> kiln on
> a concrete slab with two layers of hardbrick in the floor. Just
> after he
> finished salting the slab exploded. Fortunately everyone was well
> back from
> the kiln and no one was injured or worse, but all the pots and
> shelves were
> a total loss and the bricks all had to be broken apart. I really
> learned a
> valuable lesson there. Keep heat away from concrete, including
> cement board
> and concrete block. They won't explode the way solid cast concrete
> can, but
> they will lose their structural integrity if exposed to too much heat.
> Don't take any chances.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net
> http://iweb.tntech.edu/wpitelka/
>
>
>
Vince Pitelka on thu 5 apr 12
Steve Mills wrote:
"I completely agree with you about the neccesity of IFBs and avoidance of
cement board, but I've never had a problem with concrete blocks in that
situation, though I have to say I use hollow ones where possible. I have
several kilns still working hard and well after a fair number of years that
sit on them, and three that are on solid blocks. With Ruth's kiln in SC the
hollow blocks used are identical to those available in the UK."
Hi Steve -
I never said anything against building kilns up on a concrete block base or
foundation. Every kiln I have ever built has been up on a concrete block
base. I said that the kiln floor should be three layers of brick with at
least the bottom layer being softbrick. I like using two layers of
softbrick and then a layer of hardbrick for the hotface but on a salt, soda=
,
or wood kiln I would use one layer of softbrick and two layers of hardbrick=
.
I always use a double layer of 1/2" fiberglass-reinforced cement board on
top of the cinderblock to give a good, level base upon which to lay the
floor. I also always lay the cinderblock with the holes facing upwards,
because that is how they are engineered to be used and to have maximum
strength. I don't want to see a cinderblock crack a few years after I buil=
d
a kiln, and if you place the cinderblocks with the holes facing upwards
there will never be any chance of that. Some people place cinderblock with
the holes sideways thinking that this cools the space under the kiln, but
that shouldn't even be a consideration, because the whole point of a proper
kiln floor is that excessive heat will never gets through to the
cinderblocks. As long as the floor is adequate, there is no reason for
ventilation under the kiln.
I have never heard of cement board of cinderblocks (concrete blocks)
exploding from exposure to excessive heat, but they will deteriorate
completely from excess heat. A cast concrete slab or foundation, on the
other hand, will explode in spectacular fashion if exposed to excessive
heat. It is important for people to realize that cast concrete in a slab o=
r
cast foundation is never completely dry. It stores large amounts of
moisture for it's lifetime, and even an old slab will explode if exposed to
excess heat.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/
Edouard Bastarache on thu 5 apr 12
Vince,
I built mine with, like you, concrete blocks upright but fill with mortar
sand up to 1" to the rim. Then we leveled everything with a good layer of
mortar.
Its the way they start building bottoms of steel furnaces going from 90 to
150 tons of liquid steel, they have to be very strong.
Plejkore,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://smart2000.pagesperso-orange.fr/bloggs_edouard.htm
http://www.facebook.com/edouard.bastarache
jonathan byler on thu 5 apr 12
what's the advantage of two layers of hardbick as opposed to one?
less corrosive to the soft bricks?
On Apr 5, 2012, at 6:25 PM, Vince Pitelka wrote:
> Steve Mills wrote:
> "I completely agree with you about the neccesity of IFBs and
> avoidance of
> cement board, but I've never had a problem with concrete blocks in
> that
> situation, though I have to say I use hollow ones where possible. I
> have
> several kilns still working hard and well after a fair number of
> years that
> sit on them, and three that are on solid blocks. With Ruth's kiln in
> SC the
> hollow blocks used are identical to those available in the UK."
>
> Hi Steve -
> I never said anything against building kilns up on a concrete block
> base or
> foundation. Every kiln I have ever built has been up on a concrete
> block
> base. I said that the kiln floor should be three layers of brick
> with at
> least the bottom layer being softbrick. I like using two layers of
> softbrick and then a layer of hardbrick for the hotface but on a
> salt, soda,
> or wood kiln I would use one layer of softbrick and two layers of
> hardbrick.
>
>
> I always use a double layer of 1/2" fiberglass-reinforced cement
> board on
> top of the cinderblock to give a good, level base upon which to lay
> the
> floor. I also always lay the cinderblock with the holes facing
> upwards,
> because that is how they are engineered to be used and to have maximum
> strength. I don't want to see a cinderblock crack a few years after
> I build
> a kiln, and if you place the cinderblocks with the holes facing
> upwards
> there will never be any chance of that. Some people place
> cinderblock with
> the holes sideways thinking that this cools the space under the
> kiln, but
> that shouldn't even be a consideration, because the whole point of a
> proper
> kiln floor is that excessive heat will never gets through to the
> cinderblocks. As long as the floor is adequate, there is no reason
> for
> ventilation under the kiln.
>
> I have never heard of cement board of cinderblocks (concrete blocks)
> exploding from exposure to excessive heat, but they will deteriorate
> completely from excess heat. A cast concrete slab or foundation, on
> the
> other hand, will explode in spectacular fashion if exposed to
> excessive
> heat. It is important for people to realize that cast concrete in a
> slab or
> cast foundation is never completely dry. It stores large amounts of
> moisture for it's lifetime, and even an old slab will explode if
> exposed to
> excess heat.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net
> http://iweb.tntech.edu/wpitelka/
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