Earl Krueger on sun 25 apr 04
On Apr 25, 2004, at 06:17 US/Pacific, Bruce Girrell wrote:
> my MFT-inspired Stak-O-Brix kiln
Bruce, by "Stak-O-Brix" I take it to mean you used no mortar
between them. True or not? (couldn't find Stak-O-Brix in
the archive).
What are the advantages/disavantages of "gluing" the bricks
together? The books don't seem to talk about that very
much.
Earl K...
Bothell, WA, USA
Jennifer Boyer on sun 25 apr 04
I mortared soft bricks together when I built my first kiln. This made
the bricks unusable for a rebuild. I've rebuilt this kiln twice when
moving my studio.... I imagine others too have had to move their
perfectly servicable kilns well before a rebuild would have been
necessary. In my second rebuild I didn't mortar the softbrick and was
glad, since I needed to move the kiln again and could use all the
bricks to do the 3rd rebuild.
It could be that the kiln isn't as tight loose-stacked as it would be
mortared. I've done some filling of cracks with fiberfax...
Jennifer
On Apr 25, 2004, at 11:40 AM, Earl Krueger wrote:
> On Apr 25, 2004, at 06:17 US/Pacific, Bruce Girrell wrote:
>> my MFT-inspired Stak-O-Brix kiln
>
> Bruce, by "Stak-O-Brix" I take it to mean you used no mortar
> between them. True or not? (couldn't find Stak-O-Brix in
> the archive).
>
> What are the advantages/disavantages of "gluing" the bricks
> together? The books don't seem to talk about that very
> much.
>
> Earl K...
> Bothell, WA, USA
>
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************************
Jennifer Boyer
Thistle Hill Pottery
Montpelier, VT
http://thistlehillpottery.com
Dave Finkelnburg on sun 25 apr 04
Earl,
If I may interject, with mortar you have tight seal, a major advantage
in a reduction kiln. This assumes minimal mortar is used. Since mortar is
weaker than the insulating brick over the life of the kiln, too much mortar
can cause problems over time.
The thinner the kiln walls, the greater advantage mortar provides in
strength as well as seal. For 9-inch kiln walls, as in Bruce's kiln, you'd
have to have a huge (1/2-cm, 1/4-inch or so) gap somewhere to get much gas
flow (leakage) through the gap.
One disadvantage of mortar is you can't take the kiln down easily and
rebuild it in another configuration if you change your other mind about the
design you like.
Good potting!
Dave Finkelnburg, on a sunny spring day in Idaho
----- Original Message -----
From: "Earl Krueger"
Sent: Sunday, April 25, 2004 9:40 AM
> Bruce, by "Stak-O-Brix" I take it to mean you used no mortar
> between them. True or not? (couldn't find Stak-O-Brix in
> the archive).
> What are the advantages/disavantages of "gluing" the bricks
> together? The books don't seem to talk about that very
> much.
pdp1@EARTHLINK.NET on sun 25 apr 04
Hi Dave, all...
Could one not use say, as thin Kaowool or the like, in lieu
of Mortar?
To have one's layed-up seams snug?
Phil
el ve
----- Original Message -----
From: "Dave Finkelnburg"
> Earl,
> If I may interject, with mortar you have tight seal, a
major advantage
> in a reduction kiln. This assumes minimal mortar is used.
Since mortar is
> weaker than the insulating brick over the life of the
kiln, too much mortar
> can cause problems over time.
> The thinner the kiln walls, the greater advantage
mortar provides in
> strength as well as seal. For 9-inch kiln walls, as in
Bruce's kiln, you'd
> have to have a huge (1/2-cm, 1/4-inch or so) gap somewhere
to get much gas
> flow (leakage) through the gap.
> One disadvantage of mortar is you can't take the kiln
down easily and
> rebuild it in another configuration if you change your
other mind about the
> design you like.
> Good potting!
> Dave Finkelnburg, on a sunny spring day in
Idaho
Bruce Girrell on sun 25 apr 04
> Bruce, by "Stak-O-Brix" I take it to mean you used no mortar
> between them. True or not? (couldn't find Stak-O-Brix in
> the archive).
Exactly. The kiln if cube shaped, like a Minnesota Flat Top and uses an MFT
type roof. No mortar anywhere.
> What are the advantages/disavantages of "gluing" the bricks
> together? The books don't seem to talk about that very
> much.
The main reason that I started building my kilns like this (this is now my
third) is that we have been planning on moving "soon" and I wanted to be
able to disassemble the IFB and take it with me.
Just off the top of my head, here is what I could think of for advantages
and disadvantages
Advantages:
1) semi-portability - the kiln can be dismantled fairly easily
2) ease of construction - the bricks are simply placed on top of one another
and rubbed a little to take off any high spots and to seat them
3) thermal expansion is distributed along the joints, which are free to
move, so no big cracks develop
4) expandability - as with any MFT, if you decide that you need more height,
raise the roof and add a few more courses of brick. With a little more work,
you could dismantle a wall or two and add more width and/or length
Disadvantages:
1) lots-o-leaks - if you want a completely sealed kiln environment, this is
not the design to use. Use one of Hank Murrow's beauties instead. Most of
the time I'm firing in reduction so I have a positive kiln pressure and
outside air can't get in anyway
I'm not sure what other disadvantages it has. Probably the more experienced
kiln builders can think of something. It serves my purposes, though.
Eighteen cubic feet internal volume. I use two Ransome B3 burners and have
to keep them throttled back to 3 psi to avoid zooming past cone 10 (actually
this is right in line with Marc Ward's BTU/hr charts, maybe just a touch on
the efficient side). Swinging door on the front to allow use as a raku kiln
as well.
Bruce "any other questions?" Girrell
Paul Herman on sun 25 apr 04
Hello Earl and All,
Several people have noted that after using mortar, it's impossible to
recycle your bricks for the next kiln. The wet stuff that comes in a can
has cement in it, and makes your $3.00 bricks a "one time" proposition.
If you make your own kiln mortar, without cement in it, you CAN clean
the old bricks easily.
I use this mortar, measured by volume:
1 kaolin
1 fireclay
1 grog or silica sand *
* (a refractory grog like Kyanite would propably be best)
When you take down the brickwork to repair or rebuild, the clay based
mortar scrapes off easily with a putty knife, leaving a nice, clean,
reusable brick. I also believe that by NOT cementing the whole wall into
one monolithic unit, the bricks can move individually as they heat and
expand, and you get less wall cracks.
Oh, and keep the joints as thin as possible.
Good building,
Paul Herman
40 degrees West X 120 North
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
>Subject: Re: Stak-O-Brix kiln - To morter or not?
>Date: Sun, Apr 25, 2004, 10:03 AM
>
>> What are the advantages/disavantages of "gluing" the bricks
>> together? The books don't seem to talk about that very
>> much.
Dave Finkelnburg on mon 26 apr 04
Phil,
You have an interesting, creative thought! I have never considered this
possibility. The kaowool would compress more in the tight places, less in
the loose spots, so improve the seal, and yet still not permanently alter
the brick. However, the use of kaowool or the like would be time-consuming,
I would think.
All the best!
Dave Finkelnburg
----- Original Message -----
From:
Sent: Sunday, April 25, 2004 1:27 PM
> Could one not use say, as thin Kaowool or the like, in lieu
> of Mortar?
> To have one's layed-up seams snug?
Roger Korn on mon 26 apr 04
I've been using a mix of 16- screened IFB grog and local kaolin, 3 to 1 by weight, as a
patching mortar and kiln lid coating. The ratio is important: the amount of kaolin must be just enough to fill
the interstices between the grog particles. That way, no shrinkage or cracking occurs,
either in drying or in firing. And the mortar bond is weaker than the bricks, so no shear
failure occurs in the bricks as the bricks expand and contract over firing cycles. The problem
with cementing the bricks is that you then have large monolithic expances of kiln wall that
are heating and cooling unevenly enough that stresses build up until the bricks fail, resulting
in fractures that run across many bricks.
For general consumption, I'll try using EPK instead of the local kaolin that I dig from a road cut
and see if the 3:1 ratio (grog:kaolin) still works. The Verde Valley where I live offers about any
material you need, because of the varied geology, so I tend to dig materials instead of buying them
- still not efficient if I was a real potter like Paul, but it provides me with entertainment and
gives me a way to integrate Earth Science and Ceramics for curriculum modules that are salable
in the local secondary education market - we have lots of charter schools around here, so I get away
without formal teaching certification.
Roger Korn
Paul Herman wrote:
Several people have noted that after using mortar, it's impossible to
recycle your bricks for the next kiln. The wet stuff that comes in a can
has cement in it, and makes your $3.00 bricks a "one time" proposition.
If you make your own kiln mortar, without cement in it, you CAN clean
the old bricks easily.
I use this mortar, measured by volume:
1 kaolin
1 fireclay
1 grog or silica sand *
* (a refractory grog like Kyanite would propably be best)
When you take down the brickwork to repair or rebuild, the clay based
mortar scrapes off easily with a putty knife, leaving a nice, clean,
reusable brick. I also believe that by NOT cementing the whole wall into
one monolithic unit, the bricks can move individually as they heat and
expand, and you get less wall cracks.
Oh, and keep the joints as thin as possible.
Good building,
Paul Herman
--
McKay Creek Ceramics
In OR: PO Box 436
North Plains, OR 97133
503-647-5464
In AZ: PO Box 463
Rimrock, AZ 86335
928-567-5699
Ivor and Olive Lewis on mon 26 apr 04
Dear Friends,
If the purpose of the "Mortar" is to eliminate passage ways between
the interior and the exterior of the kiln to prevent the ingress of
air which would negate and spoil a reducing atmosphere then an
"Adhesive" material should not be used.
I have found that a refractory paste such as thick Kaolin or an
ungroged Fireclay slip is ideal. In addition, I suggest that as they
are being laid, bricks should be dipped into plain water before the
Kaolin slurry is spread on them. The aim is to get the minimum
separation between the mating faces of bricks and ensure each is
sealed to its neighbour.
Using a fine silica sand is an interesting idea. With repeated firings
this will slowly degenerate due to quartz inversion, ensuring that
there is no adhesive activity and guaranteeing the separation of the
bricks when the kiln is dismantled
Best regards
Ivor Lewis. Redhill, South Australia
of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Lee Love on mon 26 apr 04
Dave Finkelnburg wrote:
> One disadvantage of mortar is you can't take the kiln down easily and
>rebuild it in another configuration if you change your other mind about the
>design you like.
>
Another alternative is to use fireclay as a mortar. It cleans up
easier than mortar but gives you some seal. And too, only the hot face
becomes hard, allowing the rest to flex with the kiln. Olsen speaks
about this effect in his kiln book.
--
Lee in Mashiko, Japan http://mashiko.org
Hank Murrow on mon 26 apr 04
On Apr 26, 2004, at 8:28 AM, Roger Korn wrote:
> The Verde Valley where I live offers about any
> material you need, because of the varied geology, so I tend to dig
> materials instead of buying them
> - still not efficient if I was a real potter like Paul, but it
> provides me with entertainment and
> gives me a way to integrate Earth Science and Ceramics for curriculum
> modules that are salable
> in the local secondary education market - we have lots of charter
> schools around here, so I get away
> without formal teaching certification.
Dear Roger;
When I think of those kids getting to see rocks in their native beds,
processing them, and making pots with them..............well it chokes
me up. Great work!
Cheers, Hank
Steve Mills on thu 29 apr 04
As usual coming late to a thread:
I always dry lay hard bricks, but many kiln builders I know *mortar*
IFBs with 1mm or 2mm Ceramic Fibre Paper; seals them up a treat, and
stops them *wearing* with kiln expansion and contraction. In both cases
everything is held together by the kiln frame, or in my case with angle-
iron on the corners and threaded rods tying them together. It goes
without saying that alteration or rebuild is dead easy.
Steve
Bath
UK
In message , pdp1@EARTHLINK.NET writes
>Hi Dave, all...
>
>
>Could one not use say, as thin Kaowool or the like, in lieu
>of Mortar?
>
>To have one's layed-up seams snug?
>
>
>Phil
>el ve
--
Steve Mills
Bath
UK
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