Marianne Lombardo on sat 1 dec 01
I came across this recipe, and tried it on Tucker's Mid Red stoneware. =
My firing had a slow cooldown to 1700F. The colors came out subtle and =
rich, nearly black background, with a lot of olive/tan mottling and =
streaking, and rich coppery red both where pooled on the bottom of bowl =
shape as well as in the carved patterns on vertical walls of the pot. =20
It seems to have survived a 24-hour vinegar test, although I'm going to =
continue the vinegar for 3 more days and see what happens.
Is it possible that a slow cooling can make a glaze more durable?
Rosies Red
29.7 Flint
5.0 EPK
19.8 Kona F-4 Feldspar
13.9 Talc
31.7 Gerstley Borate
plus 15.0 RIO
Marianne Lombardo
Peterborough, Ontario, Canada
Ron Roy on sun 2 dec 01
Hi Marianne,
The short answer is - yes - slow cooling can improve durability because
good melting is one of the factors. This aspect has not been tested however
- so the question remains - what kind of glazes can benefit and by how
much.
This glaze is short of alumina as so the resistance to alkalies would be
more likely - keep a test tile in the dish washer and a control tile out to
compare to see if any long term deterioration takes place.
Glaze degeneration from acid takes place on the inside glaze - alkali
degeneration takes place inside and out.
Next time you are in a restaurant check the china - many of those glazes
are not all that good - you will be able to tell which kind of attack is
happening - look for loss of shine.
RR
>I came across this recipe, and tried it on Tucker's Mid Red stoneware. My
>firing had a slow cooldown to 1700F. The colors came out subtle and rich,
>nearly black background, with a lot of olive/tan mottling and streaking,
>and rich coppery red both where pooled on the bottom of bowl shape as well
>as in the carved patterns on vertical walls of the pot.
>
>It seems to have survived a 24-hour vinegar test, although I'm going to
>continue the vinegar for 3 more days and see what happens.
>
>Is it possible that a slow cooling can make a glaze more durable?
>
>Rosies Red
>29.7 Flint
>5.0 EPK
>19.8 Kona F-4 Feldspar
>13.9 Talc
>31.7 Gerstley Borate
>plus 15.0 RIO
>
>Marianne Lombardo
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
Marianne Lombardo on mon 3 dec 01
Ron;
Thanks for the reply. I only made one test bowl, but next time I fire I
will do two more. One will go in the dishwasher and I'll just leave it
there. I suspect it probably won't stand up to long-term dishwashing, but
I'm curious now to try and see for sure.
The set of everyday china that we use at home that we bought about 4 years
ago has long lost it's shine, and the colours in the pattern have faded to
pastels.
> This glaze is short of alumina as so the resistance to alkalies would be
> more likely - keep a test tile in the dish washer and a control tile out
to
> compare to see if any long term deterioration takes place.
Marianne
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