Llewellyn Kouba on tue 1 jun 04
This winter I made 97 tile pavers. They are stoneware approx. 9.5 x
13.5. In one load of bisque I blew 7 of them up and in a subsequent
smaller load I had more problems. I assumed they were not dry enough so
waited 2 months and still have a few cracking. I am trying to figure out
what goes wrong? I know the one inch thick is some of the problem. I used
a heavy molochite grog at 13%. It may be that some of the mix when applied
into the plaster mold was on the dry side and where ever I placed a wad
that is where it separated or cracked in the kiln? any one have
experiences they can relate with the thicker work. I guess I am going to
have to take some loss on a bigger project like this and count it just
that. Painful in labor and $ but seems like that is how it is going to
go. I need almost 100 total but by the time I redo for loss I will be higher.
Llewellyn Kouba
Abbey Pottery
Llewellyn Kouba on tue 1 jun 04
Also forgot to mention that I have glazed 7 of them and they are fine. Once
they are through the bisque procedure I do hope I won't have any further
problems? I would NOT want to have a glazed item blow and have never had
this happen ever and would not want to find out. I am assuming if the
pavers make it through the bisque I am home free. Any input would be
appreciated.
Llewellyn Kouba
Llewellyn Kouba on wed 2 jun 04
Michael,
Thanks much for the input on the pavers. I fired today and didn't push the
kiln but I certainly didn't have that many hours but will make a note of it
for future. Also once the pavers are bisqued did you also do the glaze
fire very slow as well? or could you fire them pretty much as regular
ware. Did you encounter any problems with the glaze load or just the
bisque I would assume. Also I placed my pavers side ways on the kiln shelf
so if any of the shelves were badly bowed then the tile would have less
curved surface to rest on. They just fit that way without any sticking
over. I'll let you know how many the total fire had and how many loss.
Hope not too many in this firing.
Llewellyn
At 11:41 AM 6/2/2004 -0700, you wrote:
>Llewellyn ,
>I ran into high losses doing the pavers
>for the Sacajawea Memorial at Salmon,
>Idaho too.
>The way I solved it was to slow the
>firing rate to 24 hours of prewarming
>the tiles at a low candle followed by a
>very slow rise rate. I takes 3 times
>longer to fire such things as is does
>regular pots. The loss rate fell to zero
>after I slowed the firing down.
>One added side note:
>We freeze-thaw tested the pavers
>over dozens of cycles by soaking
>them in a bucket of water during the
>day, then popping them into the
>freezer each night. After 30 such cycles,
>they showed no sign of spalling so I figure
>they will last a long time in the ground.
>Regards,
>Michael Wendt
>Wendt Pottery
>2729 Clearwater Ave
>Lewiston, Idaho 83501
>USA
>wendtpot@lewiston.com
>www.wendtpottery.com
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
Michael Wendt on wed 2 jun 04
Llewellyn ,
I ran into high losses doing the pavers
for the Sacajawea Memorial at Salmon,
Idaho too.
The way I solved it was to slow the
firing rate to 24 hours of prewarming
the tiles at a low candle followed by a
very slow rise rate. I takes 3 times
longer to fire such things as is does
regular pots. The loss rate fell to zero
after I slowed the firing down.
One added side note:
We freeze-thaw tested the pavers
over dozens of cycles by soaking
them in a bucket of water during the
day, then popping them into the
freezer each night. After 30 such cycles,
they showed no sign of spalling so I figure
they will last a long time in the ground.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
John Britt on thu 3 jun 04
Stephani,
Are you making your own clay? And what cone are you firing to? Also what
is the climate where the tile will be installed?
Hoping to help,
JOhn Britt
www.johnbrittpottery.com
Michael Wendt on thu 3 jun 04
Llewellyn,
They seemed to do fine in a normal glaze
load cycle after they were bisqued. I made
sure they didn't hang over the edge of the
shelf.
How are you making yours? I threw mine
on the cloth bats so recommended by Vince,
Dannon and many others and they helped
keep them dead flat.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Llewellyn wrote:
Also once the pavers are bisqued did you also do the glaze
fire very slow as well? or could you fire them pretty much as regular
ware. Did you encounter any problems with the glaze load or just the
bisque I would assume. Also I placed my pavers side ways on the kiln shelf
so if any of the shelves were badly bowed then the tile would have less
curved surface to rest on. They just fit that way without any sticking
over. I'll let you know how many the total fire had and how many loss.
Hope not too many in this firing.
Llewellyn
Llewellyn Kouba on thu 3 jun 04
Michael,
What size pavers did you do when you worked on the Sacajawea Memorial ? how
thick etc. I would like to try and find some kind of ball park estimate
what an 9x13 ( 8 x 11 finished ) would be valued at? ..total for.100
tiles. Any clue. These are fired to cone 9 gas reduction. I need to put
a value on these for the books here even though I made them for myself etc.
Llewellyn Kouba
Abbey Pottery
At 11:41 AM 6/2/2004 -0700, you wrote:
>Llewellyn ,
>I ran into high losses doing the pavers
>for the Sacajawea Memorial at Salmon,
>Idaho too.
>The way I solved it was to slow the
>firing rate to 24 hours of prewarming
>the tiles at a low candle followed by a
>very slow rise rate. I takes 3 times
>longer to fire such things as is does
>regular pots. The loss rate fell to zero
>after I slowed the firing down.
>One added side note:
>We freeze-thaw tested the pavers
>over dozens of cycles by soaking
>them in a bucket of water during the
>day, then popping them into the
>freezer each night. After 30 such cycles,
>they showed no sign of spalling so I figure
>they will last a long time in the ground.
>Regards,
>Michael Wendt
>Wendt Pottery
>2729 Clearwater Ave
>Lewiston, Idaho 83501
>USA
>wendtpot@lewiston.com
>www.wendtpottery.com
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
Stephani Stephenson on thu 3 jun 04
Hi Llewellyn and Michael
I will also be undertaking a project for about 800 square feet of
large pavers ....project still in the concept stage and I have not yet
detailed the bid
with my client.
I know I will need to account for a greater deal of R and D time on
this project.I will need to narrow down my choice of clay, and also do
some tests with adapting the body for this project. I will also be
making different sizes, of rectangles and squares , some may be as
large as 18" square, though I may have to retreat to 14" square as the
largest size.the largest ones will likely need to be 'built' with some
walls anbd hoolowd on the backside, as opposed to a single slab...
needless to say I will hav e to experiment with the best solution on
the largest ones.
Figuring the bid is indeed difficult as I need to consider that there
may indeed be a higher incidence of cracking and warping, as you
describe, Michael, just due to the increased size.Pavers will possibly
have colorant mixed into the body as well.
My pavers will not be glazed so the issue of freeze/thaw with regards
to glaze fit is not an issue, but I will still need to test for
freeze/thaw rigourously.
Seems like the key is striking a good balance....enough grog in body
to allow for good performance in the warping/shrinking/ non slip
surface categories. yet not allowing the body to become too porous, so
that it stays within acceptable limits on absorption.
Mine will not be in a climate as harsh as Idaho or the Dakotas with
regard to freeze/thaw, but will be in a climate that does have some
mild winter conditions on occasion, so exterior and must be serviceable
when wet, and durable.
I would love to see your tiles at the memorial, sometime, Michael. I
bet they are gorgeous, and also yours Llewellyn.
Stephani Stephenson
steph@revivaltileworks.com
http://www.revivaltileworks.com
Frank Bales on fri 4 jun 04
Llewellyn, wow, sounds like quite a project. You wouldn't happen to have
any photos would you? Not that I could help you figure out your problem.
I'm just a beginner, but such a project is just fascinating to me. My first
thought is what kind of clay body do commercial tile pavers use? --FrankB
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Llewellyn
Kouba
This winter I made 97 tile pavers. They are stoneware approx. 9.5 x
13.5. In one load of bisque I blew 7 of them up and in a subsequent
smaller load I had more problems. I assumed they were not dry enough so
waited 2 months and still have a few cracking. I am trying to figure out
what goes wrong? I know the one inch thick is some of the problem. I used
a heavy molochite grog at 13%. It may be that some of the mix when applied
into the plaster mold was on the dry side and where ever I placed a wad
that is where it separated or cracked in the kiln? any one have
experiences they can relate with the thicker work. I guess I am going to
have to take some loss on a bigger project like this and count it just
that. Painful in labor and $ but seems like that is how it is going to
go. I need almost 100 total but by the time I redo for loss I will be
higher.
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