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Casting - black silver


#1

I cast two pieces , an orchid and a rose, in fine silver, since I
enamel these silver flowers. Using centifugal casting, melting the
metal with a torch — they were cast separately, in two flasks.
The rose metal looked normal, silver, while the orchid metal was
dark, evenly black. I have been trying to remove the black surface
with pickle and an hour in my tumbler ,with little improvement. Any
help and an idea of why this happened would be appreciated.


#2

Do you mean to say you burned out two flowers literally? Or wax
models or? When I see a discolored surface like you describe, I
consider the burnout temperatures and timing, and perhaps metal
temperature. Way too hot can cause odd reactions with investments in
general, though fine silver should be fairly resistant to that.

Daniel Ballard


#3

I started with live flowers ,burned them out and cast them. Then I
made a mold of the silver flowers, made waxes, and used the waxes
for this part. It was the orchid wax that resulted in the black
silver. I now think that I heated the flask too much while I was
melting the fine silver. Its higher melting point probably made the
process too long.


#4

Hi, It sounds like you cast the orchid in sterling, which when cast
comes out black as we all know. If you are using metal from the
same source for both pieces, then perhaps one of your burnouts was
incomplete, and you have burned particles in your finished casting.
Fine silver does not oxidize. Oxidation happens in reaction to
copper (at least when you’re talking about silver). It is therefore
highly suspicious that your “fine” silver, was actually sterling,
and if it is sterling, then a few minutes in the pickle should clean
it right up.

— david thorp


#5

Now that’s interesting. I’ve been trying to cast bleeding heart
flowers, and the investment mushed them. I’ve frozen them, and
sprayed them with Krylon, to no effect. I’ve thought of doing an
alginate mold, but am not sure how to proceed.

Janet Kofoed


#6

Janet, freezing and spraying really destroys them. Use the natural
flower, fully hydrated. Have the investment yogurt consistency.
Spoon the investment in when you get to the area of the flower.
Allow it to dry without disturbing the flask — no vibrator! Marion


#7

Just as another possible method for creating fine silver flowers…

PMC works great for producing duplicates of organic materiasl, such
as flowers. It can be thinned into “slip” or paste and painted right
onto the flower, twig, bud, etc. After painting 7 or 8 coats, you
fire the piece as usual, burning out the organic and sintering the
silver clay. I have an article scheduled for the Spring 2003 issue of
Studio PMC that has some pretty good photos of fine silver orchids,
magnolia buds, wisteria pods, etc. made with this method, as well as
instructions. We’ve also done other articles in the past about using
PMC with organics. If you want to check it out further, visit the PMC
Guild website at www.pmcguild.com, and look in the magazine archives,
or visit the forum.

Suzanne

Suzanne Wade
Writer/Editor
Phone: (508) 339-7366
Fax: (928) 563-8255
@Suzanne_Wade1
http://www.rswade.net


#8

Janet,

I Have successfully cast bleeding heart flowers many times, though
it has been a number of years since I did it last. Do not freeze
them. Simply pick them, spray then with a good lacquer, let it dry
and cast. The problem you are having may be due to freezing them
first or it may be with the Krylon. I don’t remember what I lacquer
I used. They came out just beautiful.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2