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volcanic ash glazes...of the raku variety...

updated wed 30 apr 97


Lori Leary on sat 19 apr 97

In teaching raku classes, I have sometimes found it a headache to juggle
glazes with various maturing temperatures. After reading Mel Jacobson's
article on volcanic ash glazes in the November/December Claytimes, I had
an idea.....What would happen if I altered the proportions of Volcanic
Ash and Gerstley to create a base raku glaze? For those that have not
read the article, Mel discusses using a 60/40 Volcanic Ash/Gerstley mix
and firing from a range of ^1 to ^6.

For raku, I changed the proportions to 20/80 Volcanic Ash/Gerstley.
Using this base glaze over Highwater's Phoenix resulted in pots with the
best crackle I have ever seen in a raku glaze. The surface ranged from
satin to glossy, depending on how high I fired. I then tried various
oxides and stains. For example, with 2% copper carbonate, I have gotten
lovely blue/green crackle, copper lusters, and copper reds, depending on
how I handled the post-firing reduction.

My students enjoy mixing their own recipes, I no longer have to worry
about glazes with different maturing temperatures, and it is easy to
fill out my purchase orders. And best of all....we make good pots.

Lori Leary
Pawleys Island, SC USA

Dannon Rhudy wrote:
> -------------Original message----------------------------
> Jeff
> There is an article in Claytimes dealing with some of the uses
> of volcanic ash as a glaze ingredient. It was two issues ago,
> I think, or perhaps three.
> Mel Jacobson wrote the article.
> Dannon Rhudy