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Bronze casting


#1

Hello Everyone!

I am planning on coming out with a line of bronze pieces. I also
want to make some brooches as well and I have never ever soldered
bronze before and I was wondering how much of a pain would it be to
attach a pin back. Also can I solder steel backs on easily or base
metal to bronze?? Last question, is bronze lighter or heavier then
sterling silver??

Thanks in advance!!
PS still trying to find a bronze chain source… any leads??

dd


#2

According to my charts, true bronze has a S.G. of 8.8 (sterling is
10.4). It solders like copper (flux is your friend).

If you are going for historical accuracy, I can tell you from my own
reading and research, that a lot of pieces identified as bronzes in
museum catalogs are as likely brasses, leaded brasses and
"gunmetal", as being “bronze”. That’s one of the reasons that
archeologists and museums have taken to using the phrase “copper
alloy”. Both the Museum of London, and the Metropolitan Museum have
done metallurgical analysis of a broad spectrum of their pieces, and
found that the alloys are all over the map. The problem was that a
lot of past catalogers had a tendency to look at any copper alloy
that wasn’t clearly copper or yellow brass, and stuck a “bronze” tag
on it.

Ron Charlotte – Gainesville, FL
@Ron_Charlotte1 OR afn03234@afn.org


#3

Dede, I work in base metal (although not bronze) and see no reason
you should have any difficulty soldering steel pin-backs onto
bronze. The melting point of bronze is 1945 degrees Fahrenheit,
which means that almost any solder (silver or base metal) should be
suitable. If you want a matching solder for a visible seam, I have
little to suggest (I’m still looking for a really good color match
for Nugold). Try the 1/16" rods in welding supply stores, hammer
them out and cut them into little squares for solder.

I trust you are aware of potential vocabulary problems. Certain
metal supply places refer to brass (copper:zinc) as “jewelers’
bronze” even though bronze is an alloy of copper and tin.

The specific gravity of bronze is 8.8; that of sterling silver is
10.4. (All these handy little figures come from Tim McCreight’s
books.) HTH – Judy Bjorkman


#4

dd:

I have made lots of jewelry in cast bronze and also fabricated
brass. It is actually easier to work with than Sterling Silver.

As far as soldering findings to bronze, the findings themselves are
often the problem not the bronze. Soldering surgical steel is a
trick. Bronze works well with fusion findings also.

Ken Gastineau
Gastineau Studio
Berea, Kentucky


#5
If you want a matching solder for a visible seam, I have little to
suggest (I'm still looking for a really good color match for
Nugold).  

Years ago I was given a piece of a master record which was cut on a
bronze plater. This, I was told, had a lower melting point than most
bronzes used in jewelry. I have saviored that piece and , though I
have not worked with bronze that much, it has worked fine in giving
a fairly good color match to a solder seam. I don’t know if any
would be available or where one might search for it, since I do
think the technology has changed sometime ago, but you never know.
If it’s only a small piece you require, I’ll be happy to send it to
you. Joe Dule


#6

I am cross posting this from another group. I’m sure that answers
will come from orchid. You can send directly to Mike or just post as
usual and I’ll send them on to the group,artmetal.

marilyn smith

Hi All,

  I know there are a few of you who have fairly extensive bronze
  casting experience and I hope someone can help us out with
  some info. We have been using 2 casters for our product...one
  has been handling our gold and silver, the other recently
  started casting our pieces in bronze. We have had excellent
  service and consistently high quality from our gold/silver
  caster. The caster who has picked up our bronze work, however,
  has sent us a high percentage of pieces with extensive
  porosity and isvery reluctantto consider that the porosity may
  be due to something other than the waxes we send and the way
  they have been sprued. We have been successfullycasting these
  same waxes with the same spruing for over five years with
  several different casters so we're fairly confident that we
  have things reasonably nailed down on our end. 

  Anyway, the caster who has been handling our gold/silver is
  taking pity 

  on us and is going to "lower" himself, risk his hard-earned
  reputation 

  as a precious metals caster and take a crack at our bronze. He
  has never cast bronze before and asked me if I could help him
  do a little homework. We have been casting Everdur (silicon)
  bronze. Specific questions: 

  1) What is the recommended temp. at melt? 

  2) Recommended flask temp.? 

  3) What percentage (if any) new casting grain addition when
  recycling metal? 

  We are talking about small, jewelry size pieces (mostly flat,
  5/8"-13/4" oval/round pieces) and using a vacume casting
  system. Any help or pointers would really be appreciated and if
  someone with experience casting small bronze items would be
  willing to talk to him on the phone even better. He's not a
  rookie at this, just wants to know 

  as much as possible before jumping in with both feet! 

Thanks in advance,
Mike Dibble
Black Horse Design
www.black-horse-design.com


#7

I am a small manufacturer of high-end Guitar Tuning Machines. For
this I cast the base-plates in bronze using a modified vacuum casting
process. While the quality is the casting is good, I would like to
improve the surface quality by using a combination of vacuum and
centrifugal casting. Has anyone experience with that process?

Thanks
Jorg


#8

Jorg,

I would like to know more. I am planning on setting up a foundry for
casting bronze statutes.

Jerry


#9

Dear Jerry,

I would like to know more. I am planning on setting up a foundry
for casting bronze statutes. 

Statues are usually done in the art casting process where a shell is
created to do the casting. Unless you need really fine detail and
exceptional surface quality and dimensional accuracy that process
works quite satisfactorily.

If you have further questions feel free to ask.

Best
Jorg