Paul Lewing on wed 24 mar 10
On Mar 24, 2010, at 4:14 PM, gina mars wrote:
Hi All, I made a batch of my favorite purple glaze today. Somehow, I
screwed up and used magnesium carbonate instead of manganese carb.
Will this ruin the glaze completely? It's an old eggplant glaze,
You don't say how much manganese carbonate the recipe called for but
since that's a colorant, I doubt it was more than 5%. But there are
still several ways this could affect the outcome. However, there is
going to be no way to tell without testing it, but you have nothing to
lose, and maybe you've just invented the next great glaze.
If your glaze also has cobalt in it, the magnesium may make that go
pink or lavender. It wouldn't have much effect on any other
colorant. But of course, now your glaze has no manganese in it
either, so it's not going to get any purple color from manganese. I'd
test what you've got before I added any manganese back into it. You
might like it better without.
Magnesium is a flux at high temperatures. You don't say what
temperature this glaze is, but if it's midrange, a 5% addition of
magnesium might matte it quite some. If it's cone 10, it might not
make much difference. If it does make a difference, it will be toward
making it more matte, I would guess.
Magnesium carbonate is really fluffy stuff, as I'm sure you've noticed
by now and will never forget for as long as you live. It's what they
use to make those beady crawl glazes. This could be the most dramatic
effect of this change. When you do your test, if you notice that the
dry layer of glaze is cracked, you're likely to get crawling. Again,
maybe it will b e something you'll like to use.
Happy testing.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com
gina mars on wed 24 mar 10
Hi All, I made a batch of my favorite purple glaze today. Somehow, I
screwed up and used magnesium carbonate instead of manganese carb.
Will this ruin the glaze completely? It's an old eggplant glaze, Gina
Mars
www.marspottery.net
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