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Bronze and patina


#1

Hello Dear all, Please excuse me for asking questions about things I
unfortunately know very little about. However, two things have been
puzzling me and I cannot find the answers myself.

First, and most importantly, but here I have to admit my almost
complete ignorance (and there is not much about bronze in the
archives either), I feel attracted towards bronze and would like to
work with it, using centrifugal casting. Could someone please explain
a couple of essentials to me about casting bronze? This subject is
not covered (or only very slighlty) in any of the books I have. Is it
feasible without great trouble to solder bronze to Sterling silver
(using a Little Torch)? Which sort of solder should be used? And,
finally, could someone recommend a manufacturer of bronze to me?

Second, I saw a Sterling Silver brooch today (at a jeweler’s shop in
Pittsburgh). The brooch was finished with a moderately shiny blue
patina which looked very attractive to me. The blue itself made me
think of lapis, but it was not as dark. Does someone has any idea
about which patina had been used here? According to me - but I might
be wrong - it was not liver of sulphur, as I do not see how it is
possible to get a shiny blue with liver (I couldn’t ask the jeweler,
since he was busy with other customers and I had to run). Thank you,
I appreciate this group enormously. With very best regards, Will
Denayer (@W_Denayer).


#2

William,

    Hello Dear all, Please excuse me for asking questions about
things I unfortunately know very little about. 

That’s how we all learn – doesn’t much pay to ask questions about
things that you already know lots about :wink:

    Could someone please explain a couple of essentials to me about
casting bronze? This subject is not covered (or only very slighlty)
in any of the books I have. 

Try looking for books on sculpture rather than jewelry. Since
bronze casting (sand, lost wax, etc.) has a long and healthy heritage
in the sculptural arts, you will probably find much more written
about it there.

   Is it feasible without great trouble to solder bronze to
Sterling silver (using a Little Torch)? Which sort of solder should
be used? And, finally, could someone recommend a manufacturer of
bronze to me? 

Absolutely possible, and I find it quite easy. Use a regular torch,
clean and flux well, and solder as you normally would. I use silver
solder when soldering either bronze or copper to silver, because it
seems to be easier to “hide” and clean up.

As to source, I’ve gotten all my bronze sheet products from T.B.
Hagstoz in Philadelphia. I honestly don’t know whether they also
supply it in grain or scrap for sculptural casting, but if they don’t
I’m sure they would be happy to point you in the right direction.
They can be reached at 800-922-1006.

    According to me - but I might be wrong - it was not liver of
sulphur, as I do not see how it is possible to get a shiny blue
with liver 

If you play around with it, you can get a gorgeous iridescent blue
(as well as purple, rose, etc.) on silver with liver. Try it with
the liver relatively cold, and do repeated dips and rinses until you
get the color just right. You’ll be startled how many colors you can
go through this way before you start getting the characteristic
brown/blacks we associate with antiquing with liver. I have also
heard, but not tried myself, that adding a little ammonia to your
liver solution will produce more iridescence as you do this – if you
try it, make sure you do it cold, as you do NOT want to be breathing
hot ammonia fumes.

Good luck!
Karen Goeller
@Karen_Goeller


#3

William, We cast many of our designs in bronze and they make very
beautiful and unusual jewelry pieces. The bronze casting initially
started as a result of a mixup with our caster. A flask of our stuff
got accidently switched woth someone else’s who was casting in
bronze. The caster was very apologetic as she knew we were on a tight
deadline to get inventory ready for a show. We told her to go ahead
and ship the pieces to us and we would “play” with it and see how it
came out.

Well, we found that many of the pieces would take a beautiful flame
patina, giving irridescent shades of blue, blue green, violet, red,
gold and shades in between. Every piece will patina a little
differently and some just don’t seem to color at all. I suspect it’s
related to the difference in surface copper oxides from piece to
piece. Perhaps someone else knows a little more??

Anyway, the bronze items have become very popular sellers for us,
especially at fine art shows where many people are on the look out
for unusual or unique items. Also, some people just like the gold
tones but can’t necessarily afford to purchase gold jewelry. As far
as I’m aware, there is nothing different in the casting process other
than the melting point.

You are more than welcome to check our website to see some examples
of what’s possible. If you decide you want to give it a try, I can
contact our caster to find a source for casting grain and ask her if
she has any special tips for bronze casting.

Best Regards, Mike Dibble…in beautiful northern New Mexico with
sunny skies, snow, happy horses and greyhounds!

Black Horse Design
www.black-horse-design.com


#4

I have achieved the blue you talk of using diluted liver of sulphur.
In the diluted form it will not oxidize as quickly and will go
through the rainbow of colors (even purple). Have cold running water
near by to halt the reaction when you have attained the desired
color. I seal the finished work with a lacquer to halt any further
reaction (of course that is a little impractical for a jewelry
application.

Ron VanOstrand
http://www.auroragoldsmiths.com


#5

Has anyone found a laquer that will work on jewelry after
application of liver of sulphur? …

Thanks
Linda


#6
    Has anyone found a laquer that will  work on jewelry after
application of liver of sulphur? 

I don’t have any experience with it yet but Sculpt Nouveau
(www.sculptnouveau.com) sells a product called Incralac. It is
designed specifically for protecting patinas on outdoor sculptures. I
think they sell it in small quantities. If not, they can direct you
to a distributer who does. I know the manufacturer only sells in 5
gallon quantities! They claim it doesn’t chip, yellow or flake but I
imagine a frequently worn piece of jewelry might challenge its
durability.

Mike Dibble
Black Horse Design
www.black-horse-design.com


#7

Incralac works. A laquer that works on liver of sulfur colors
without distorting them is ‘Dead clear flat matt laquer’ from Star
industries. (Texas) Remember you can sign up for Thomasregister.com
as an individual and search US manufacturers by product and service.
Envirotex works well too for this, and forms an optically flat
surface when poured on. This is a two part thing, needs to be fresh,
and probably to be bought in large quanitities to be really good. It
is used on bar tops, and is ‘self-sealing’, that is a small scratch
will smooth over by itself 9hence the bar top use) best Charles

Charles Lewton-Brain/Brain Press Box 1624, Ste M, Calgary, Alberta,
T2P 2L7, Canada Tel: 403-263-3955 Fax: 403-283-9053 Email:
@Charles_Lewton-Brai1

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#8

Morning, Incralac is made by Wattyl and you should be able to buy it
from a paint/hardware store in 1L tins. Incralac is used in museums
to coat metals. It will yellow but it takes at least 10 years in a
museum environment. Incralac contains a compound called
Benzotriazole (BTA) that helps prevent corrosion(specifically
chlorides) of copper and its alloys. I usually dilute it (with
acetone 50/50) for dip coating medals. I am unsure of its wearing
properties as I work in a museum and the medals are court mounted and
no longer worn. I can tell you that anything that will scratch the
coating will also scratch the metal and any coating underneath it. I
think that the main worry would be the acidity of the persons’ skin.
While Incralac will offer some protection, I do not think it is
deisned to stand up to acidic conditions, however mild. I guess if
you’re going to use it, you may need to do some testing. Eileen
Procter Metals conservator Australian War Memorial