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topic 17977

How to make bronze p3



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A discussion started in 2002 but continuing through 2018

February 1, 2012

Q. I want to know which is the best copper alloys for the investment casting. And what is the proportion of copper and other metals. and I also want to know which bronze suitable for this castings.

Ankit Adeshara
- Baroda, Gujarat, India

March 23, 2012

Q. Okay, bronze is 90% Cu and 10% Sn. Or perhaps it's 88% Cu and 12% Sn. But how is this percentage defined? Percent by mass (mass fraction)? Or percent by relative number of atoms (mole fraction)?

Jim Luschen
- San Diego, California, USA


March 25, 2012

A. Hi Jim.

Bronze, and all alloys, and most mixtures are described by mass fraction. Compounds, in contrast, are often described by mole fraction: H2O (water), is two atoms of hydrogen to one atom of oxygen.

I suppose the reason is that chemical compounds react with each other molecule by molecule, whereas mixture proportions are more conveniently described by weight. Sometimes, though, mixtures are described by volume fraction: in making cookies, you might use two cups of flour to one cup of sugar.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey



March 27, 2012

Q. "Moses then made a serpent out of bronze and raised it as a standard, and anyone who was bitten by a serpent and looked at the bronze serpent survived."

How did he do this in the desert living as sort of a nomad?

John Flynn
- Sun Prairie, Wisconsin, USA


March 27, 2012

A. Hi John. The bronze age preceded the iron age in every culture; it's not high technology at all, so casting bronze serpents was easy enough for nomads.

But curing snakebite by lasering antidote in through the eyes is very advanced technology, and probably would have to be ascribed to divine intervention rather than the science of an ancient nomadic culture :-)

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


March 27, 2012

thumbs up signCool!

John Flynn
- Sun Prairie, Wisconsin, USA



May 31, 2012

info... While copper/tin is what's used for making for making Bronze today, copper/arsenic was commonly used in ancient times. In fact it was probably the most common type of bronze in the early bronze age. Arsenic is very poisonous and that's probably why copper/tin bronzes became more common later in the bronze age.

In addition to using homemade charcoal-fired furnaces to melt copper, tin and bronze, you can also build charcoal furnaces to smelt (smelting: To extract a metal from it's naturally occurring ore) copper tin and even iron. Smelting doesn't require temperatures that would melt the metal being extracted. It works by a chemical process called "reduction" where oxygen is removed from the metal oxide in the ore. The reducing agent in these furnaces is the carbon monoxide gas from the charcoal fire.

www.youtube.com/watch?v=Fwo3rNLhlmI

Rod Brandon
- Tucson, Arizona


June 13, 2012

Q. I am glad I stumbled upon this site as it provides some interesting and verifiable information on bronze casting. I am writing a fiction novel and have been searching for answers to these questions, but I am lacking the proper knowledge of metal working to figure out how the bronze hardens. What I mean by this is that after a sword is cast, it is then worked, or forged by the smith, hardened, for use. I have come across other sites that have shown how late Bronze Age swords were just as effective as early Iron Age swords due to advances in metal working, and increasing knowledge. The answer I have come across seems to be saying that bronze hardens after being worked over with a hammer, the exterior of the metal being harder then the center, making a sword more effective. I guess I am looking more for confirmation that bronze hardens when hammered, effectively tempering the blade.

Dwayne Wallage
- Halifax, NS, Canada


September 25, 2012

A. About bronze vs. iron. My understanding is that bronze is quite hard as cast. Early iron, on the other hand, was relatively impure cast iron which is very brittle. Only when forging was invented as a technique did iron become better. However the raw materials are more common. Roman officers had bronze swords while the troops had iron ones, I've been told.

Ian Chandler
- Cambridge, UK


December 5, 2012

A. You CAN use pennies to make bronze if they are pre-1982 which are all copper. Then you take a little tin (on top) and put it on a hotplate. I've seen it done before without a fancy kiln or oven type thing. It's fairly simple but just keep in mind that melting pennies IS illegal :D

Lexii Valentine
- USA


January 2014

Hi Lexii, although it's theoretically illegal, when the intention is education it's not going to be a practical problem. What WILL be a problem is buying thousands of pennies, melting them down, and selling them for their copper value -- which exceeds their face value :-)

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


January 20, 2013

A. I came across a series of three DVDs that explore the process of making bronze, including full do-it-yourself instructions for making a backyard foundry. I found these videos at Survival.com. Respected outdoorsman Ron Hood went to Romania researching the roots of bronze-making. Although I'v not seen this particular video I've watched his primitive knifemaking video that includes making your own forge. His videos are always well done and informative. http://www.survival.com/?page_id=76

Bo Gulledge
- Louisville, Kentucky, USA


May 23, 2013

Q. Hi, I'm 13 and was wondering where did people get the stuff to make bronze at. HELP! I need good answers. Thanks.

Taylor Cave
- Dayton, Ohio, USA



January 5, 2014

Q. I have an ornate, many-armed chandelier that was roughly handled and bent. Can I heat parts of it to gently return to its original position. Maybe use a torch? What do you recommend I do to restore it?

Margaret Piper
- North Little Rock, Arkansas


January 2014

A. Hi Margaret. And you're sure this chandelier is solid bronze?

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


January 7, 2014

Q. I think so, because it is an antique, very old.

Margaret Piper
- north little rock arkansas


January 7, 2014

A. Bronze is very brittle and hard to work. If you try to bend your piece around much it is apt to break.

dave wichern
Dave Wichern
Consultant - The Bronx, New York


January 9, 2014

A. Try to heat it to dark red colour ,when it is cold try to bend it but very very carefully. Repeat process several times and don't use too much force. Old bronze is very brittle metal. Best approach -- try to find professional metals conservator. Hope it helps and good luck!

Goran Budija
- Zagreb, Croatia


January 1, 2016

A. The way they learned to make brass in the ancient world happened by a process of elimination. They grew things. And kept them in earthen pots. When sugar goes bad from fruit it creates alcohol which degrades into acid. It changes things in the earthen vessels. By watching they probably dipped different utensils into the pots. Or things just to see what it would do to the thing. By this process you could primitively create brass through electroplating. Which would be improved on over thousands of years. Metal being smelted or superheated and mixed in liquid form was not possible till much later. 6870 years ago till 2018 years ago was a primitive time in most societies and a endeavor like smelting was probably in the infancy of anything we would call a process. 2018 years ago to about 1400 would be the time that I'd focus on to look for advancing metallurgy. And solid metallurgy from 1400 to present.

Matthew Bugg
- Wellington, colorado, usa


December 8, 2016

A. You can make a homemade furnace it little dangerous but be safe; wear protective gear as on leather gloves, have proper tongs and safety glasses. You can use charcoal or propane or other gases and make sure to have a good air flow. I use a hair dryer and I would prefer to use a graphite crucible.

Robert h. [last name deleted for privacy by Editor]
- Mason, west Virginia, usa


December 7, 2017

Though bronze is most often made from copper and around 10-15% tin you can also make aluminum bronze. Aluminum bronze is a little tougher than regular copper/tin and has a bit more of a 14-22 kt gold color. It's the same process as regular bronze but you use 8-11% aluminum instead of tin. If you have the means you can also add up to 4% nickel and 2% silicon which will also make the bronze more durable.

To produce the amount of heat needed, just under 2000 °F to pour bronze, you can use an old steel rim or old brake drum from the junk yard as the fire bowl, some (ungalvanized) pipe and a T fitting. Find a friend or family member with a welder and weld the fitting to the center hole of the drum or rim so that ash can fall straight out the bottom. Screw a piece of pipe into the horizontal part of the fitting and shove a blow dryer into it. Screw a pipe cap loosely into the bottom hole so the air will travel into the bowl.

Once that is done, put a small metal plate with holes drilled in it over the air supply so your fuel doesn't fall in but plenty of air can come out. Load it with charcoal, coal or smithing coke over a ball or newspaper and light the paper. When it is lit petty good turn the blower on and let it heat up. Getting a coal fire started well take practice and coke is even harder do it's often easier to start the fire with charcoal or wood then add the coke or coal after until you get it figured out. You can also wrap duct tape around the opening where the hairdryer is so you don't lose as much air pressure.

The fire produced is hot enough to melt steel so please be very very careful. I would invest in a clay/graphite crucible, and they are not too Spendy and will make your life easier. Always always always wear eye protection, preferably brazing goggles and a face shield. Always wear cotton or natural fiber clothing like wool because synthetic cloth will melt to your skin; and always use welding gloves when handling molten metal and a larger welding apron. Water is your enemy with molten metals also. Do not quench (cool in water or other liquid) until you are 110% sure the metal is no longer molten. Patience is very important here, kiddos. Always use tongs to remove and pour the crucible. It may not be glowing red but it will burn the meat off your hands down to the bone. I am very sure these guys can fill in what I forgot but have fun and be very safe.

I love hearing about younger generations showing interest in the old metallurgical arts. I'm a blacksmith by trade, making Damascus knives, but at times I cast parts for my knives and just because it's fun. I would love to pass some knowledge on to inquisitive minds. Best of luck kiddos :)

Daniel Price
Owner of Tine Anam Blacksmithing - Mansfield, Texas, USA


July 6, 2018

A. This is an extremely old thread … but if anybody really wants to know how to cast bronze and a couple of recipes search youtube.

opinion! I was looking to increase my bronze making abilities and came across this thread. Horrible how people treat a sponge-like mind …

Phillip R Amburgey
- Garden City, Michigan, United States.


July 2018

A. Hi Phillip. Thanks for the update. I would call a thread spanning 16 years "long-enduring" rather than "extremely old" :-)

Youtube is great, but I also see a value in dialogs where dozens of people contribute and we get lots of perspectives balancing each other.

I'm not understanding who you feel was horribly treated though.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"



December 4, 2018

Q. Can anyone tell me if adding 90% (by mass) copper plumbing pipe to 10% old pewter tankard will produce a reasonably machinable bronze? thanks in advance ; Paul (50 years old and still learning)

Paul Hucknall
- Settle, North Yorkshire, UK


December 6, 2018

A. Hi Paul
That should work but I would melt the copper first and then add the pewter. You will not be able to get the pewter hot enough to melt the copper without serious oxidation of the tin.
Copper melts about 1083 °C tin 232 °C and bronze 913 °C

Assuming the pewter is modern it will be mostly tin and the lead content will help machinability.
The other minor metals in pewter will tend to make your bronze near old formulations where such things were not easily controllable.

But a simpler way might be to visit your local scrap yard and collect worn out bronze bearing shells.

geoff smith
Geoff Smith
Hampshire, England


December 8, 2018

thumbs up sign Thanks Geoff,
I will visit a scrap yard, but also try the other as I have a lot of copper and pewter available, although I guess the scrap yard would take the copper anyway...

Paul Hucknall [returning]
- Yorkshire, UK



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