I just bought a pound of Rio Grande’s “Ancient Bronze” casting grain
for experimentation. I’m thinking of using it either as a supplement
to my line of silver animal charms, or just to cast my one-offs and
test carvings for mold-making. Before I set about ruining things,
I’d appreciate any suggestions anyone might have on working with
this stuff. Thanks in advance!
Kathy Johnson
Feathered Gems Pet Jewelry
http://www.featheredgems.com
If it is true Ancient Bronze, it is a mixture of copper and tin. Can
be reactive to skin oils/acids and the high copper can create a
problem with some molding rubbers via the copper salts that will form
on the surface and inhibit RTV catalization (giving you a sticky mold
surface).
Do some testing before you go crazy with it.
John Dach
Greetings:
I use it both in my historical line, and for my students. There’s
nothing tricky about it. Other than a slight color difference, it
handles a lot like Everdur or Herculoy. (Two more ‘standard’ jewelry
bronzes. They’ve both got Zinc in them, so they’re technically red
brasses, but that’s another argument.)
It’s a little on the viscous side when casting, but nothing
horrible. (Molten silver is about as runny as milk, while most
bronzes are closer to real (thin) maple syrup, if that makes any
sense. It’s on the thicker end of that scale.) Works just fine with
either centrifuge or vacuum casting. It’s more formable than standard
bronzes due to the fact that it really is a bronze, and thus has
no zinc to harden it. I’m not sure what you’re doing with it, so I
don’t know what else to tell you. Do not fear it. Play, and learn.
For whatever that all’s worth.
Brian
Brian,
Just to clear one thing you stated about Everdure having zinc in it.
It doesn’t, just Herculoy does. Everdure is very easy to weld (TIG
mostly) as no zinc and it is a bit healthier to melt and work with
because of the lack of zinc. Everdure is a bit more difficult to
patinate than Herculoy, again because it it, Everdure, does not
contain any reactive zinc. As to coloration of any of these 3
alloys, ancient bronze can give some absolutely beautiful reds and
oranges compared to the Everdure or Herculoy. All of these alloys
art “thicker” than silver when poured, but the zinc in Herculoy does
make for a bit easier casting.
John Dach
Hi,
Ahh! interesting…so…Rio Grande’s Ancient Bronze (casting grain) is 90% copper, and 10% tin…no zinc…
Ancient Bronze Casting Grain - RioGrande
so I am thinking/ hoping it is able to be pulse arc welded…(as the above poster mentioned…) as one alternative to soldering with non-matching solders…
(zinc is problematic for welding because it’s boiling point is very low (1664.6 F) whereas the boiling point of tin is 4715.6 F, and copper is 4643.6 F)
the brasses I am seeing are copper/ ZINC/ and possibly other elements…and Bronzes are copper/ TIN/ and possibly other elements…(it is the other elements that I am trying to avoid…)
some of the bronze strip and wire that I am seeing have other elements in them…
the Rio Grande Ancient Bronze seems to be only copper/ tin…I think I will get some casting grain and attempt to make some wire and sheet…cleanliness seems to be a factor…I must research further!
Julie
Hi,
interesting post from the past…regarding bronzes and brasses…i thought i would repost/ share
julie
Wow I bought this too several months ago. Would love to see any casting results from you guys so that I know what I’m getting into…So my understanding from this conversation is that the zinc free bronze won’t react as well to patina solutions…? I purchased two varieties from Sculpt Nouveau has anyone here tried that brand’s solution on ancient bronze castings…?
It’s not that bronze (copper-tin) won’t react as well, just that it reacts differently from brass (copper-zinc).
McMaster-Carr, an industrial supplier, has very good information on the different copper alloys and what their uses are.
The most comprehensive book I know of on the subject of patination is Hughes and Rowe’s The Colouring, Bronzing, and Patination of Metals. It is out of print but used copies can be found from time to time. It is also available to read online at the Internet Archive. The file cannot be downloaded as it is still under copyright, but there is no time limit on how long you can read it online.You need to set up a free account, and only one account can “borrow” it at any given time, so you may get a “currently unavailable, try again later” message.
I use “Special H silicon bronze” from Belmont Metals Inc. to cast belt buckles I sell on Etsy. Melts at a higher temp by torch or gas furnace. Very recastable. I just keep reusing the sprues and buttons. If I need to do any repairs, I laser weld with bronze TIG wire. I get a nice black with Berg selenium toning solution. (used for photographic toning prints) I get this from B & H Photo in New York. Apply full strength to work with a brush or cue tip and heat with a torch. Hot, but not red. Wash off and then do a little more if necessary. Stays on good. Does not come offf in ultrasonic.
