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Copper or bronze casting


#1

Hello Orchidians, I’m a relatively new subscriber and have been an
avid “read-only” participant until now. What a tremendous resource
this is! And what a terrific community of generous, interesting
folks. Now I find that I have a question I’d like to put out there.

I’ve been using a fair amount of copper in my work lately, generally
heat-patinated and in combination with other metals. Some time ago I
bought some little knobbly copper spheres at my local rock shop. They
look more or less like copper wasabi peas. I fell in love with them,
used them in some pieces, went back to buy more and – alas! –
Down-to -Earth Dave at the rock shop said that (a) he didn’t really
know what they were (b) the guy who brought them in was a stranger
and © he’d never seen him or the peas again and didn’t know where
to get more. I’ve searched the net, corresponded with rock hounds,
etc etc but no dice. No more copper wasabi peas. So. I am not a
casting person. But in desparation I’ve decided to get a mold made
from an actual wasabi pea (of which there is a virtually
inexhaustable supply at Whole Foods), and try to get some cast. My
questions (“FINALLY,” I hear you saying) are these:

The common wisdom is that you can’t cast copper, or at least nobody
does. Is this true? If it isn’t true, who does it? I want at least
the surface of the peas to be copper, and thick enough that it can
take and retain patination with heat. Harry at Alpine Casting told me
that he doubted that plating with copper would deposit a skin thick
enough to allow for decent heat patination or longevity.

The other possibility is to get them cast in bronze. But it would
have to be a really red-brown bronze, not the yellow-ish silicon
bronze all the casters seem to use. But what bronze, and from whom?

Does anyone have suggestions for me on either front? I’d prefer the
copper but I’d settle for the bronze. I’m in the Chicago area, where
you’d think one could find anything. If only one knew where to
look…

Thanks to all, in advance, Carla in Evanston, IL, home of the bunny
vortex (bet you didn’t know that this is where they make ALL the
bunnies – the factory is actually in my yard)


#2

Copper is cast but it does have problems with oxygen or hydrogen
adsorption. The bronze alloys reduce this problem and increase
other properties. You can make casting grain like you would make
silver grain by pouring molten copper. I would suspect that what
you bought was Phos-copper shot that was made to add to bronze
melts to deoxidize them. This can be bought from suppliers to the
foundry industry. Jesse


#3
    The common wisdom is that you can't cast copper, or at least
nobody does. Is this true? 

Somewhat, it is a difficult “dirty” metal to cast by itself.

 If it isn't true,  who does it? 

I don’t really know.

    The other possibility is to get them cast in bronze. But it
would have to be a really red-brown bronze, not the yellow-ish
silicon bronze all the casters seem to use. But what bronze, and
from whom? 

“Ancient Bronze” an alloy of about 85% copper and 15% tin is
somewhat reddish and can take on a beautiful reddish patina with
heating. It can be bought but is pretty easy to alloy yourself
(copper {wire scrap} and tin {pewter suppliers re ROTO METALS in San
Francisco, but there are others especially on the East coast and
England, areas where pewter is cast}). There are other alloys (red
bronze, red brass etc, check out copper alloy suppliers (Atlas
Metals in Denver Colorado is one of many).

    Does anyone have suggestions for me on either front? I'd
prefer the copper but I'd settle for the bronze. I'm in the Chicago
area, where you'd think one could find anything. If only one knew
where to look... 

Post this to the ArtMetal.com community via the techtalk area or
sign up (free) and post to the list. A Metal workers in the arts
list (jewelers, sculptures, casters, fabricators) with a great base
of knowledge.

    Thanks to all, in advance, Carla in Evanston, IL, home of the
bunny vortex (bet you didn't know that this is where they make ALL
the bunnies -- the factory is actually in my yard) 

What do these “beads” look like? Are the hollow and or rough
round?? If so they may be made via dropping molten metal in a long
tube or pipe (no wind) so the metal cools before hitting the ground
(roundish but generally solid forms) or molten metal dropped into
water (roundish forms but most often hollow). If either of these
shapes (varied diameters but could be screened and the “odd sized
stuff” re melted and re poured).

Just some thoughts. Also the bit about thickness of the copper
taking on a patina, not much is needed, the bigger problem is
wearing it off.

John Dach


#4

This is a little off the subject from the original post, but I just
wanted to mention that copper is cast in Nepal.It is used
fortraditional Buddhist statues.

I spent two years there working with a family that does wax work and
casting. So I had a good chance to see a number of castings.I take
that back, they really put me to work, so I wasn’t just seeing, I was
doing.Anyways,I would say that the alloy used is 90-95% copper w=
ith
some pieces of bronze (of indeterminate alloy, I have even seen old
faucets go into the mix) . The benefits of using the copper come
when they do the finishing work on the statues.The copper allows fo=
r
a greater amount of detail and deeper patterns. They will planish the
entire surface with smoooth punches.Then, they will use chasing
tools to add all of the details of the cloth, face, hands, and
hair.The copper also allows them to create their preferred coloring
for the statues.They will gild portions of the statue (yes, with
mercury) and then color the rest of the metal with a warm
reddish-brown color, finally adding paint for the details on the
face.

Most of the statues that are in the average shops are tourist (low)
grade.However, many Tibetans with means are eager to acquire statue=
s
of the highest quality, so there are a few producers of masterpieces.
Can you tell I am really en thusiastic about this subject?!?If an=
y
of you are venturing to Nepal, I would be happy to send you to the
heart of the metals community.Oh, and you can see some of the
sculptures I made in Nepal at www.artnatasha.net

Warmest wishes to all

Natasha Wozniak

natasha@natashajewelry.com

www.artnatasha.net