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Onglaze Question Percentage Of What?


Babs

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I've been reading an old Ceramics Monthly mag, highly recommended so informative, and onglaze recipes by  John Fassbinder had me wondering .

The colourants are written up as %s and I can't see what they are percentages of......Be kind to old ladies.

Eg

Blue/Brown:

2% Manganese Dioxide;

1% Cobalt Oxide;

1/2%Rutile and

1/2% talc.

This was fired to a Cone 10 reduction.

Another question.

Can Talc be used as an onglaze ingredient at lower temps?

he revives them by adding water.

So what are these chemicals percentages of?

Or are they written as this incase someone wants to use them as colourants in glazes?

His onglazes melt into the glazes beautifully

Babs

 

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It's a percentage of the total glaze that you are mixing. If you have a glaze test of 100 grams-2% manganese would be 2 grams. That is if you were adding it to a glaze. I would try it at 1% assuming it was a glaze test. Mix it up in a cup based on a total of 100 grams, then brush it on. The talc is there as a flux to cause it to melt into the glaze surface.

TJR.

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bciske, no base glaze... just the onglaze recipes. It stated that he just kept his onglazes in old coffee mugs and added water as he needed...I thought initiallly that it would be in 100ml  water, but wouldn't matter and I gues this is the case.

TJR I am taking from your comment that I'd mix a ratio of 1:2:0.5:0.5  in order of listings which is what I usually do for onglazing

So the talc is ok as a flux at C6? I usually use neph syn or a frit.

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Question:  Which "old" CM issue has this article?

 

Without more details about the article, my take is that %s means percent solids in the water-solids mixture.  100 grams water + x %s grams of the specific ingredients.  In effect the onglaze decoration is an oxide wash over the glaze already applied to the pot (cups in this case).  Unlike a single component oxide wash, his onglaze concoction needs several oxides (or ingredients) in a particular ratio to produce his desired effect.  The  %s nomenclature assures that the wash, when thoroughly suspended, provides the ingredients in the needed ratios.

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bciske, no base glaze... just the onglaze recipes. It stated that he just kept his onglazes in old coffee mugs and added water as he needed...I thought initiallly that it would be in 100ml  water, but wouldn't matter and I gues this is the case.

TJR I am taking from your comment that I'd mix a ratio of 1:2:0.5:0.5  in order of listings which is what I usually do for onglazing

So the talc is ok as a flux at C6? I usually use neph syn or a frit.

 

Looking at his work, I'm inclined to think it for an oxide wash or for decorating . . .

 

post-2190-0-77472400-1429303732_thumb.png

post-2190-0-77472400-1429303732_thumb.png

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The Ceramics Monthly is November 1979.

Thanks everyone. I think the amount of water will be variable and JF , as he allows it to sit in old coffee mugs, just knows what consistency he needs.

He uses these mixes for onglaze dec. which melt into the glaze, I'll post a pic later.

IS it ok to photo out of a mag to post here?

This guy throws/threw one piece goblets from the hump.  solid stem and foot, does anyone do this now?

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