Nancy LT Hamilton 3/28/24
Bronze is one of my favorite metals for jewelry making, teaching, and making models. Phosphor bronze has a warm gold color that mimics 14k gold. It makes a nice accent with silver, creating a color contrast. Working with bronze is similar to working with sterling silver – although it’s a bit harder and work hardens a tad faster than sterling. Bronze has a range of melting temperatures higher than sterling (893° C – 1640° F). Bronze ( 950° C to 996° C- 1742° F – 1825° F – depending on the alloy). This temperature variance is great for beginners – there’s less chance of a “meltdown”. Phosphor bronze – one that is made with around 89% – 95.5% copper, 3.5% – 10% tin, and 1% phosphorus will give you greater freedom to work the metal as it hardens slower than a bronze made with zinc. This means less annealing! It is more ductile and easier to work with than alloys with zinc.
*Note: I always enjoyed working with Rio Grande’s bronze. I’m not sure of the exact alloy, though. I know that it was a Copper/tin/phosphorus alloy. If anyone knows the exact proportions, or if I’ve got that wrong, please let me know! Thanks.
There are a zillion bronze alloys, and not all of them will work for jewelers! Read on…
So, what is the best bronze for jewelers to use? IMHO, one with an alloy close to the one Rio used to carry. It’s a phosphor bronze either C51000 or C54400. (C544 at Online Metals). C54400 is an alloy of around 88% – 95.5% copper, .5% – 11% tin, and .01 – 1% phosphorus. (These alloys drive me nuts! So many variations!!!) Online metals carrys it in varying gauges. If you are casting with bronze, one of my favorites is available at Rio Grande. It’s called Ancient Casting Grain and is 90% copper, 10% tin. Here’s the link. Rio has a variety of other casting grains.
Brass, bronze, and copper also have antimicrobial properties! I have heard of hospital research using bronze or brass equipment to combat hospital-borne viruses and bacteria. That’s pretty amazing. Also see Copper Facts: Antimicrobial Copper
Avoid bronze that is alloyed with lead. Lead’s periodic table symbol is Pb – (in BOLD under Types of Bronze below). Watch out for leaded commercial bronze #C31400
Bronze Links
Best Bronze for Jewelry – Post on Ganoksin
Copper Development Association
A Guide to Different Types of Bronze Alloys – Metal Tech International
Everything You Need to Know About Bronze – Rotax Metals
Tips for Working with Bronze
Bronze often has a copper-colored coating on it after soldering or even annealing. This can be fixed by placing it into Super Pickle. Super pickle is simply a 1/2 measure of hot, sodium bisulfate pickle mixed with 1/2 hydrogen peroxide. Drop the metal into the super pickle and wait a moment or two. You can watch as the copper dissipates – it happens so quickly! Don’t leave the metal in the super pickle unless you want a matte finish, as the SP will etch into the bronze – chewing away the copper. Leave the SP out overnight; pour it back into your pickle pot the next day. The hydrogen peroxide will have reverted to water by then.
Air cool bronze slowly, as rapid cooling may cause fracturing and/or crumbling. In other words, don’t quench it when its super hot! The annealing temperature is around 260° C (500° F) depends on the alloy.
Chart from Fire Mountain Gems – Melting Points of Metals

Traditionally, bronze is an alloy of copper (88%) and tin (12%). Brass is copper and zinc. Other metals are added to copper and are still called “bronze,” so be careful about the type you choose for jewelry making. Some of the other metals (also metalloids and non-metals) that are added to bronze are manganese, aluminum, nickel, lead, phosphorus, etc. Modern bronzes can cross the line into more brass-related metals, so understanding the alloys used in the bronze that you purchase is essential. Often, bronze is called a copper alloy. Be careful with this, as this can also refer to types of brass.
See the periodic table for symbols – (Link to the National Library of Medicine)
Types of Bronze
Alloy numbering system: Brasses (C20000 – C49999) Bronzes (C50000 – C69999) The C stands for copper-based. The copper-based system runs from C00001 – C99999. There are also Wrought and Cast numbering systems. Cast metal is harder, more brittle, and less malleable than wrought metal. The numbering system for wrought copper alloys is C50000 – C 70000, and for cast copper alloys, C80000 – C90000. See the Engineer’s Edge for more classifications.
- Aluminum Bronze – various alloys (link to Wikipedia – also see the Copper Development Association)
- Architectural bronze – 55% – 59% copper, 40% zinc, 3% lead (considered a brass alloy) (link to Architectural Metal Polishing)
- Arsenical bronze – Arsenic is often found naturally with copper. Arsenic lowers the electrical conductivity of copper (link to Wikipedia)
- Bearing Bronze 81% – 85% copper, 6.3% – 7.5% tin, 6% – 8% LEAD, 1% – 4% zinc, 1% nickel, less than 1% antimony & iron – (Link to Sequoia Brass and Copper)
- Bell Bronze – aka C91300, Cymbal Bronze – is generally 76% – 80% copper and 18% -24% tin. Used for musical instruments, pistons, bearings, bushings, etc. Highly rigid because of the high tin content.
- Bismuth bronze – Copper and tin with 1% – 6% bismuth – very corrosion resistant.
- Commercial bronze – Aka C23000, 90% copper, 10% zinc (Link to Atlas Bronze) Avoid LEADED commercial bronze (C31400)
- Gilding metal – Aka C22000 red brass or C23000 commercial bronze. Used for bullet casings. Alloy falls in the range of red brass and commercial bronze. Alloys I’ve seen run from 95% copper, 5% zinc to 85% copper, 15% zinc. Anneals at 800° F to 1450° F (427° C – 788° C). Cool slowly. (Link to Wikipedia)
- Gunmetal – Aka C23000 or red brass. Casts and machines well, corrosion resistant by steam and seawater – approx. 88% copper, 8% – 10% tin, 2% -4% zinc. Modified gunmetal can include LEAD
- High-silicon bronze “A” – C65500.This high-strength engineering alloy is highly resistant to many corrosives, including salt and fresh water, most acids, alkalies, salts, and organic chemicals. It is used for electrical conduits, tie rods, rivets, nails, etc.
- High tin Bronze – C92700 thermal conductivity and high ductility. It doesn’t work harden as easily as bronzes made with mostly zinc.
- Jeweler’s bronze – Aka commercial bronze. Actually BRASS. 85% copper, 15% zinc
- Jeweler’s manganese bronze – Actually BRASS. Casts well, yellow gold, pouring range 1700°F – 2100°F (926.67° C – 1148.89° C). 60% copper, 35% zinc 5% manganese, and other metals. (Link to Belmont Metals)
- Manganese bronze – see above
- NuGold – Actually BRASS. 85% copper and 15% zinc (Link to Contenti)
- Phosphor bronze – .5% – 11% tin, .01% – .35% phosphorus, can also contain .5% – 3.0% LEAD – check with the manufacturer to be sure yours doesn’t contain LEAD – (link to Wikipedia). This is approximately the alloy that I use. Online Metals carries it.
- Red Brass – Aka C21000, C22000, C23000 (same as Red brass), 90% copper, 10% zinc, and C23000 (same as Commercial bronze), 85% copper, 15% zinc and 80% copper, 30% zinc. It also falls in the range of Gilding Metal.
- Silicon bronze – C65100. Predominantly (around 96%)copper with trace amounts of manganese, zinc, tin and sometimes aluminum or Pb – LEAD: 0.05% max. Corrosion and pitting resistance. Used for tubing, welding rods, hydraulic products, etc. (link to Britannica )
- Sintered bronze – SAE 841. Iron 1.0% max, tin 9.5% – 10.5%, carbon/graphite – 0.3% max, other elements 1.0% max, the rest, copper. A bearing material. Used for equipment, hydraulics, and mining.
- Speculum bronze – usually 66% copper, 33% tin – makes a white alloy that is very brittle. Historically, it was used to create reflective surfaces like mirrors (link to Wikipedia)
Bronze alloys are designated by a number system called the Unified Numbering System. Following is a partial, and in some cases, an abbreviated numeric chart of some bronzes found on Online Metals (they can send small pieces and will cut to size – but they don’t have high tin bronze [see below])
The Copper Development Association, Inc. lists pretty much all of the copper UNS numbers and their alloys – among other things. Look up any of them there – my brain hurts and I think I’m done with this page for now!
- 220 – Aka commercial bronze—it is actually BRASS as it has a higher zinc content than tin (90% cu, 10% Zn). Rich color, excellent formability, corrosion resistance, and high strength. Used for medals, medallions, jewelry, hardware, lighting fixtures, kickplates, push plates, weather stripping, and marine hardware.
- 510 – Phosphor Bronze – High formability, fatigue resistance, and corrosion-resistant springs. .5% – 11% tin, .01% – .35% phosphorus, can also contain .5% – 3.0% LEAD the rest copper
- 544 – Phosphor Bronze – High formability, fatigue resistance, and corrosion-resistant springs. .5% – 11% tin, .01% – .35% phosphorus, can also contain .5% – 3.0% LEAD the rest copper
- 614 -C 61400. Max: Lead 0.01%, zinc 0.20%, iron 3.5%, phosphorus 0.015, Aluminum 8.0%, Manganese 1/0%
- 623 – C62300. Aluminum bronze. 9% aluminum.
- 630 – Nickel aluminum bronze – corrosion resistant, very high strength that also requires superior toughness and ductility.
- 632
- 642 – Silicon aluminum bronze – self-lubricating properties and high strength
- 651
- 655 – Silicon bronze – corrosion resistance, high machinability, bearing properties. Si: 2.80–3.80%, Mn: 0.50–1.30%, Fe: 0.80% max., Zn: 1.50% max., Pb – LEAD: 0.05% max., Cu: balance – usually around 96% depending
- 673
- 863 – Manganese bronze – If strength and longevity are required in heavily lubricated environments.
- 932 – Bearing bronze – when excellent machining and anti-friction are required also good wear resistance.
- 937
- 954 – Aluminum bronze – When high strength, excellent corrosion, and wear resistance are required. Ease in casting. Aluminum 4% – 11.5%, Nickel .8% – 6%, iron .5% – 6%, Manganese 5% – 2%, zinc 5% max, arsenic .4% max, the rest in copper
- C54520
- C89835 – Bismuth Bronze – When lead-free material is needed, very corrosion resistant. Copper and tin with from 1% – 6% bismuth
- C95510
- SAE 841 – Sintered bronze – High strength, temperature resistance, and wear resistance with oil impregnation.
- SAE 863 – Manganese bronze – The SAE designation means that it is cast. (Society of Automotive Engineers – SAE) – If strength and longevity are required in heavily lubricated environments.