I have used Silver PMC3 to make some end caps. I have fired them
all ready and they are ready to be used as is; but I would really
like to fire them again using a Raku glaze which is mainly used for
ceramics. There are no instructions as to firing temperature that
came with the glaze. Can someone tell me what temperature should I
fire the silver again with the glaze on it. I don’t want to go to
high and melt the silver.
According to Tim McGreights book on Precious Metal Clay, he says that
firing the PMC3 again with a ceramic glaze can be done; but there
were no temperature there either. I have already tried 1450 degrees
F. Supposedly when the glaze is hot enough it will look wet and
glossy. At that point, I am suppose to put it in a can of
combustible material such as dried leaves, paper shavings, etc. and
let it smolder; but I can’t seem to get it to the point where it has
the wet glossy look. Can someone guide me as to proper temperature
to use in my kiln that will not melt my silver end caps. This is
very new to me.
I have seen silver jewelry made with raku glazes, but they were
definately “immature”-- bubbly, craggy and matt. My past experience
with raku suggests to me that the usual glazes mature higher than
your melting point-- 1800 or so, if I remember right. In any case, I
think your best bet might be to look up a ceramic supply catalog
such as Aftosa, Minnesota-Midwest Clay, or search under “ceramic
supply” and take a look at their pre-mixed glazes. Temp info should
be given. If you are really determined, you could probably find a
company or, better yet, a potter who will work with you to formulate
something that melts in the right range. The best potters all mix
their own glazes and understand how to adjust firing temp.
Ceramic glazes come in many types and fire at different
temperatures. Ceramicists tend to use a system called “cones” for
determining firing temperature–this dates back to the days before
modern pyrometers were available. Chances are, your Raku glaze has
“cone xxx” on the label. If we know that, we can go to a chart and
determine the actual temperature in degrees. What does the label
say?
Thanks so much for the suggestions. I checked the place that I
bought the glaze from. There was no mention on their site as to cone
for this particular glaze. I will look again carefully at the bag
and see if there is any mention of that. I like your suggestion
about mixing a glaze that will work at a temperature that won’t melt
my silver work. I will email again when I have found out more
Thanks again! Jeanne
You can do Raku with enamels, which will work with PMC. I haven’t
done that but there was an article several years ago in Glass on
Metal by a friend of mine, Jean Tudor, who lives in Washington. Like
ceramics, the hot enameled silver piece is dropped into a bucket of
organic material to give an irridescent surface.
Thanks so much for that suggestion. I still haven’t gotten back out
to my shed where I store my supplies to take a closer look at the
label. Unfortunately, I have to also hold down a full-time day job;
but this coming weekend, I will again, work with the jewelry making
and look at labels; and also to check out other enameling supplies.
Thanks for responding! Jeanne
Just a note about the irridescent surfaces one might hope to get by
using a raku process-- enclosing a hot piece in a container of
combustible material to create a powerful reduction: To get those
amazing colors, your glaze or enamel must contain copper in some
form. The colors are just the same as the ones formed by playing a
torch over copper, though in glass (glaze or enamel) they are much
more durable.