high fire with no bisque firing?????

We're going to fire some hand-made tiles to cone 4 or 5, but intend that
they should be unglazed. Is there any reason to go through the usual
cycle of bisque-firing, cool down, and then high fire if the ceramics
will not be glazed? We were thinking that it would save time if we went
directly to the high fire, perhaps with a hold at the lower temperature,
or a very slow ramp rate from cone 04 on up.

Thanks

Paul


--
E. Paul Wileyto, Ph.D.
Assistant Professor of Biostatistics
Tobacco Use Research Center
School of Medicine, U. of Pennsylvania
3535 Market Street, Suite 4100
Philadelphia, PA 19104-3309

215-746-7147
Fax: 215-746-7140

http://mail.med.upenn.edu/~epw/

Paul,
It certainly would save time and a lot of energy too. I see no reason
at all to go through the twice firing process. I have to admit that I
do not know to which temp cone 4 or 5 corresponds (In france we tend to
loosely refer to the temp at which they fall rather than the number),
but if the tiles are to be un glazed the only real worry that you would
have is if you take the clay up to vitrification point without going
slow enought to give time for carbon and sulphur burn out. This would
result in bloating.

You could just attatch the tail end of a high fire onto a normal bisque
fire.

Happy firing, Alistair.

St Amand en Puisaye, France.


E. Paul Wileyto wrote:
We're going to fire some hand-made tiles to cone 4 or 5, but intend that
they should be unglazed. Is there any reason to go through the usual
cycle of bisque-firing, cool down, and then high fire if the ceramics
will not be glazed? We were thinking that it would save time if we went
directly to the high fire, perhaps with a hold at the lower temperature,
or a very slow ramp rate from cone 04 on up.

Thanks

Paul


--
E. Paul Wileyto, Ph.D.
Assistant Professor of Biostatistics
Tobacco Use Research Center
School of Medicine, U. of Pennsylvania
3535 Market Street, Suite 4100
Philadelphia, PA 19104-3309

215-746-7147
Fax: 215-746-7140

http://mail.med.upenn.edu/~epw/

Follow the same regime for a Bisque firing, but extend the finish
temperature to the desired cone.
Remember to ventilate the kiln thoroughly until it ceases to smell
sulphurous to prevent carbon build-up in the clay; this is the main
cause of bloating and blistering.
If you have a vent hole in the lid it really helps. Almost all US top
loading kilns imported into the UK have this modification as standard.

Steve
Bath
UK


In article , E. Paul Wileyto
writes

We're going to fire some hand-made tiles to cone 4 or 5, but intend that
they should be unglazed. Is there any reason to go through the usual
cycle of bisque-firing, cool down, and then high fire if the ceramics
will not be glazed? We were thinking that it would save time if we went
directly to the high fire, perhaps with a hold at the lower temperature,
or a very slow ramp rate from cone 04 on up.

Thanks

Paul



--
Steve Mills
Bath
UK

I think you can successfully once fire your tiles. I do something
similar. I make toad houses out of red clay (cone 4-6) and I was
bisque firing and then glaze firing although I didn't glaze them and I
thought it would save time and energy if I could once fire them so I
did and it works great. I even started putting a green glaze on the
toad sprig on the roof and the archway into the door when the thing was
bone dry then once fired to cone 6 and you can't tell the difference
that I didn't bisque. Good luck with your project.
Sandi








Steve Mills wrote:
Follow the same regime for a Bisque firing, but extend the finish
temperature to the desired cone.
Remember to ventilate the kiln thoroughly until it ceases to smell
sulphurous to prevent carbon build-up in the clay; this is the main
cause of bloating and blistering.
If you have a vent hole in the lid it really helps. Almost all US top
loading kilns imported into the UK have this modification as standard.

Steve
Bath
UK


In article , E. Paul Wileyto
writes

We're going to fire some hand-made tiles to cone 4 or 5, but intend that
they should be unglazed. Is there any reason to go through the usual
cycle of bisque-firing, cool down, and then high fire if the ceramics
will not be glazed? We were thinking that it would save time if we went
directly to the high fire, perhaps with a hold at the lower temperature,
or a very slow ramp rate from cone 04 on up.

Thanks

Paul



--
Steve Mills
Bath
UK

Thanks very much for your help. We will let you know how it goes.

Paul (& Carol)

Red Deer wrote:
I think you can successfully once fire your tiles. I do something
similar. I make toad houses out of red clay (cone 4-6) and I was
bisque firing and then glaze firing although I didn't glaze them and I
thought it would save time and energy if I could once fire them so I
did and it works great. I even started putting a green glaze on the
toad sprig on the roof and the archway into the door when the thing was
bone dry then once fired to cone 6 and you can't tell the difference
that I didn't bisque. Good luck with your project.
Sandi








Steve Mills wrote:
Follow the same regime for a Bisque firing, but extend the finish
temperature to the desired cone.
Remember to ventilate the kiln thoroughly until it ceases to smell
sulphurous to prevent carbon build-up in the clay; this is the main
cause of bloating and blistering.
If you have a vent hole in the lid it really helps. Almost all US top
loading kilns imported into the UK have this modification as standard.

Steve
Bath
UK


In article , E. Paul Wileyto
writes
We're going to fire some hand-made tiles to cone 4 or 5, but intend that
they should be unglazed. Is there any reason to go through the usual
cycle of bisque-firing, cool down, and then high fire if the ceramics
will not be glazed? We were thinking that it would save time if we went
directly to the high fire, perhaps with a hold at the lower temperature,
or a very slow ramp rate from cone 04 on up.

Thanks

Paul


--
Steve Mills
Bath
UK



--
E. Paul Wileyto, Ph.D.
Assistant Professor of Biostatistics
Tobacco Use Research Center
School of Medicine, U. of Pennsylvania
3535 Market Street, Suite 4100
Philadelphia, PA 19104-3309

215-746-7147
Fax: 215-746-7140

http://mail.med.upenn.edu/~epw/

"E. Paul Wileyto" wrote in message
...

We're going to fire some hand-made tiles to cone 4 or 5, but intend that
they should be unglazed. Is there any reason to go through the usual
cycle of bisque-firing, cool down, and then high fire if the ceramics will
not be glazed? We were thinking that it would save time if we went
directly to the high fire, perhaps with a hold at the lower temperature,
or a very slow ramp rate from cone 04 on up.

I have fired some very small, thin stuff glazed direct to high fire (1260).

Depending on how thick your tiles are, I would also be very careful to make
sure they were dry all the way through - ie maybe dry-fire them to 120 C for
a while to make sure all water is thoroughly out of them before going
further up in temperature.

I am curious. What are these tiles for? Decoration? Why aren't you glazing
them?

Marianne