john schaeck on fri 9 feb 01
Hello, I'm another new person to the list and to ceramic work. I must
say that the sheer number of postings is overwhelming. My question:
I have started making tiles to serve as a baseboard in a spare bedroom
having tile flooring. This is a dry environment, but I am concerned
with the strength of my tile and its resistance to impact. At the same
time I want to use low fire glazes and underglazes for the bright and
large selection of colors. In the book Handmade Tiles by Frank Giorgini
he recommends bisque firing to cone 2 but doesn't specify the clay. I
have been using a cone 5 clay (Laguna WC-397) and bisque firing to cone
2 followed by cone 06 glaze firing. The idea being that even thought
the clay is not vitrified is it stronger than if fired at a lower
temperature or stronger than an earthenware clay fired to its
vitrification point. Is this true? Do I need to fire this clay to cone
04 bisque followed by cone 5 glaze fire to get the full benefit of using
a stoneware clay? -john in Tucson.
Cindy Strnad on sat 10 feb 01
Hello, John.
I'm not a tile expert, but it's my understanding that the main strength of a
tile is in the way it's laid. If you have a good surface under the tile and
good adhesion, I can't see where it would make a lot of difference (in
durability) whether you use low-fire or high-fire clay.
You might find, though, that with the clays and firing variations you're
using, that you have a hard time getting your glazes to fit properly. Again,
this isn't a problem as long as the glaze sticks permanently to the tile,
and you like the appearance.
Floor tiles will get a lot more wear than baseboard tiles. Maybe tiles for a
bath tub would need more careful firing, too, but for what you're doing, I
don't see you having much of a problem if the tile is flat, and is installed
well.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
STVC on sat 10 feb 01
John in Tuscon-
Since I do mostly architectural tiles and sculpture, hopefully this is one
of the few questions on this list I might be able to help with.
Your tiles should be plenty strong for your application with cone 2 firing,
depending on how wild you are with that vacuum cleaner, but a couple low
tech scratch and fracture tests should give you more confidence. Another
rough indicator of the presence of partial vitrification is slow to minimal
absorption of water dropped on the surface of your unglazed tile. If no
vitrification has occurred, water will be absorbed almost instantly, and
your tile will be weak. Even a small amount of vitrification throughout the
object will give a tremendous increase in strength.
I frequently "bisque" to partial vitrification (2050 deg F) for strength,
and glaze at lower temperatures.
Assuming large pyrometric cones, the temperature range equivalent of cone
2-5 is 2124-2185 degrees Fahrenheit for large Orton cones, a difference of
61 degrees F. Vitrification begins in most cone 5 bodies somewhere between
2000 and 2100 degrees F. Vitrification of a clay body occurs along a
continuum, and is affected by several factors. Target temperatures/cones
represent mature vitrification. Slower firing cycles will produce more
vitrification in thicker objects at sub target temperatures.
Steven Van Cleave
Vista, CA
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of john schaeck
Sent: Friday, February 09, 2001 6:09 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: tile strength
Hello, I'm another new person to the list and to ceramic work. I must
say that the sheer number of postings is overwhelming. My question:
I have started making tiles to serve as a baseboard in a spare bedroom
having tile flooring. This is a dry environment, but I am concerned
with the strength of my tile and its resistance to impact. At the same
time I want to use low fire glazes and underglazes for the bright and
large selection of colors. In the book Handmade Tiles by Frank Giorgini
he recommends bisque firing to cone 2 but doesn't specify the clay. I
have been using a cone 5 clay (Laguna WC-397) and bisque firing to cone
2 followed by cone 06 glaze firing. The idea being that even thought
the clay is not vitrified is it stronger than if fired at a lower
temperature or stronger than an earthenware clay fired to its
vitrification point. Is this true? Do I need to fire this clay to cone
04 bisque followed by cone 5 glaze fire to get the full benefit of using
a stoneware clay? -john in Tucson.
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Stephani Stephenson on sat 10 feb 01
John wrote
I have started making tiles to serve as a baseboard in a spare bedroom
having tile flooring. ... I am concerned
with the strength of my tile and its resistance to impact. At the same
time I want to use low fire glazes and underglazes for the bright and
large selection of colors. I have been using a cone 5 clay (Laguna
WC-397) and bisque firing to cone
2 followed by cone 06 glaze firing. Do I need to fire this clay to
cone
04 bisque followed by cone 5 glaze fire to get the full benefit of using
a stoneware clay? -john in Tucson.
John
Many functional, serviceable and durable tile is fired well below cone
5. Though highfired stoneware is stonger, its strength is not
absolutely necessary, for baseboard or even for counter, wall or floor
tile.
I think we overbuild somethimes. It is hard to imagine lower fired clay
holding up underfoot, but it has worked well for centuries.
We make cone 04- 02 tile and trim. We glaze the tiles raw and once
fire. We have experimented with custom clay bodies and now use a terra
cotta body similar to Laguna's cone 5 red sculpture body. I haven't
used the WC-397 so can't advise you on that particular body. If you are
firing to cone 2 and your cone 06 glazes fit, no crazing or shivering,
you should be OK. Remember, the tile will be bedded nicely in thinset or
some other adhesive.
Make sure your baseboard is well designed. No sharp edges, thin
projections or fragile outcroppings.
Try scratching your samples with a coin, stain them with cofee, dirt,
ink, and see if it wipes off, etc. . That will help you determine if the
glaze is suitable and durable. Just some personal observations, Good
luck!
Stephani Stephenson
http://www.alchemiestudio.com
http://home.earthlink.net/~mudmistress/
Rebecca Gregory on sun 11 feb 01
Hello Everyone! This is my take on the floor tile issue. Let me say that I
do work at Lowe's Home Improvement, and for those who don't know what Lowe's
is, it is like Home Depot. As far as floor tiles go, there are several
different ratings for them. There are tiles made specifically for wall
ornament only. These tiles are under fired white low fire clay.
The way I understand it is that reason most floor tiles are matte is the
slippery when wet with water or grease issue. The matte glazes do hide wear
and tear of high traffic a lot better than the glossy glazes. Also, the
substrate that the tile is put on does play a factor. The ceramic tile
industry recommends that a proper substrate (meaning subfloor) should be
laid. An 1.5" of exterior grade plywood can be used, as far as my rep from
American Olean tells me, but the most preferred substrate is Durarock or
Hardibacker. These substrates are concrete based.
Anyway, each tile produced commercially is suppose to have a rating for
durability as well as for whether it is meant to be used interior or
exterior. At the newer larger Lowe's, the tiles are now shown with their
ratings, and the employees are slowly but steadily learning what these
ratings mean. I really can't remember the rating system right off the
bat...My paperwork is at work, handy to explain what it all means to the
customers.
My experience, so far with customer preference, is that they like the matte
glazes more than the glossy anyway due to texture variances, color
variations, safety factors, and cleaning issues. Just my take on things,
and really probably doesn't make much sense nor necessary information to
anyone..
Take care!
Becky Gregory
Nashville Tn
----Original Message Follows----
From: Cindy Strnad
" but it's my understanding that the main strength of a
tile is in the way it's laid. If you have a good surface under the tile and
good adhesion, I can't see where it would make a lot of difference (in
durability) whether you use low-fire or high-fire clay."
This is Cindy's reply to John who asked about the durability of tile glazes
being glossy or matte.
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Janet Kaiser on sun 11 feb 01
Sorry... Cannot help until I understand... What
is a "baseboard" please?
Janet Kaiser
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
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