Dave Finkelnburg on wed 16 feb 00
Tom's comment below is correct. In that case, 100 grams of pure Copper
Carbonate is equivalent to about 72 grams of pure Black Copper Oxide, not
the number I previously posted. I apologize for the error, and thank Tom
for the correction! Based on Vince's comment about Red Copper Oxide not
being wettable, calculating that ratio is pointless! :-)
From: Tom Buck
> Your MW for copper carb is out because the green stuff is NOT
>CuCO3 but CuCO3.Cu(OH)2, ie, a double compound combined in a crystalline
> til later. BFN. Peace. Tom B.
>Tom Buck ) >
vince pitelka on thu 17 feb 00
In response to this post, and several others I received, I must appologize
for making the following declaration is such a definitive and absolute
fashion. As I have been informed, if you add just a smidgeon of dish
detergent, the red copper oxide will blend just fine. As Tom Buck pointed
out to me, there are a number of circumstances when it is advantageous to
use red copper oxide. In Tom's own words "Why use Cu(I)2O (red oxide)? 1)
If the base glaze is a bit touchy (on a cusp), then adding less colourant
oxide may keep it ok, and you
still get the colour you want. Granted this is reaching somewhat. 2)If you
have kiln problems (eg not enough reduction should the wind be in the
wrong direction), then using red oxide may help in achieving a pot with
some red colour. 3) You may find a cheaper source of red oxide compared to
copper carbonate basic (the green powder). 4) Some Raku people who use a
copper oxide wash on the outside of their pots find they get a more
"exciting" result using the red oxide...the wash is approx 80% red oxide +
a source of B2O3 and SiO2."
My Original Post:
> << Red copper oxide has absolutely no affinity for water - it does not mix
> water-suspensions. No matter how much you blend it, it just comes right
> back to the surface. So the answers to your questions are moot.
> Best wishes -
> - Vince
> Hi Vince,
> I just ordered some Red Copper Oxide for a raku glaze and couldn't figure
> why it wasn't mixing, and just read your post. That answers my question.
> it mix with something else? Should I just brush it on and raku as normal?
> What is your experience with this oxide? Thanks.
> Vicki in Cool, CA
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