Brad Sondahl on fri 19 nov 99
I've been thinking about the theory that zinc gets vaporized in
reduction firing. But I don't have a reduction kiln. So here's a
simple test for someone who does. Post the results to the group...
Fire a small bowl without glaze to your final temperature.
Weigh it accurately on the triple beam balance.
Add an exact amount of zinc oxide to the bowl.
Fire the bowl and zinc, and note the results, particularly weighing it
when finished.
If there is a significant loss of weight, the zinc is likely vaporizing
as theorized.
This test does not necessarily show what would happen in a glaze, as it
might be protected from some of the reducing effects by the melted glaze
surrounding it.
Anyway, let me know if you try the test.
--
Brad Sondahl
http://www.camasnet.com/~asondahl/bradindex.html
Sondahl homepage http://www.camasnet.com/~asondahl
Original literature, music, pottery, and art
David Hendley on mon 22 nov 99
I've been doing 'zinc reduction tests' for several months.
The most dramatic result:
I filled a small bowl (very small, about 1 1/2" diameter)
with a teaspoon of zinc oxide, and fired it to cone 10
in heavy reduction.
I didn't weigh anything, but the zinc was gone after firing.
The only hint that it was ever present was a little white
flashing on the bowl.
It obviously vaporized.
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: Brad Sondahl
To:
Sent: Friday, November 19, 1999 11:15 AM
Subject: zinc and reduction test
| ----------------------------Original message----------------------------
| I've been thinking about the theory that zinc gets vaporized in
| reduction firing. But I don't have a reduction kiln. So here's a
| simple test for someone who does. Post the results to the group...
| Fire a small bowl without glaze to your final temperature.
| Weigh it accurately on the triple beam balance.
| Add an exact amount of zinc oxide to the bowl.
| Fire the bowl and zinc, and note the results, particularly weighing it
| when finished.
| If there is a significant loss of weight, the zinc is likely vaporizing
| as theorized.
| This test does not necessarily show what would happen in a glaze, as it
| might be protected from some of the reducing effects by the melted glaze
| surrounding it.
| Anyway, let me know if you try the test.
|
| --
| Brad Sondahl
| http://www.camasnet.com/~asondahl/bradindex.html
| Sondahl homepage http://www.camasnet.com/~asondahl
| Original literature, music, pottery, and art
|
| |
|
