bronze bars

Patina: Bringing Out the Best in Bronze Bars and Tubes


Metals are the most abundant material on the planet. The Earth’s core, itself, is a gigantic ball of iron. You can find them in almost every building, vehicle, or machine, as well as most of the everyday items you use. They comprise 77 percent of the Periodic Table of Elements—and these are just the pure metals. The alloys produced by combining two or more of them are not yet included. Simply put, metals play a critical role in how the world runs, and yet a lot of people know very little about them.

There’s more to the metals that make up your doorknob and window frame than you probably know. If you take a closer look at them, you’ll find some fascinating facts that can make you understand how vital metals are to human life. One of the most interesting things about metals is their susceptibility to corrosion, a process that results from electrochemical reactions between materials and substances in their environment.


Understanding Corrosion

When a metal is placed in an unstable environment, its chemical composition changes, particularly when it makes contact with a reactant, a substance it reacts to. Different metals react to different substances and how they react varies according to their classification. Ferrous metals, for example, slowly transform into rust when exposed to oxygen.

Non-ferrous metals or those metals that do not contain iron, on the other hand, react by forming a protective outer layer called patina. The best example of a metal that undergoes this type of corrosion is copper and all its alloys. When exposed to oxygen, copper’s surface turns green over time.

Have you ever wondered why the Statue of Liberty has a green color despite lack of coating? That’s mainly because its cladding is made entirely of copper. After over 140 years of exposure to the elements, its copper covering has long reached the final stage of its transformation, which is colored green.


When You Don’t Always Want Green

While the green color of corroded copper looks appealing to some, it does not to others. If anything, they think the color doesn’t fit to certain decorative applications and they prefer dark brown, black, or anything in between. In that case, they prefer an alloy of copper where copper’s properties are not that prominent, so they choose bronze.

Bronze has been used for making statues, ornaments, and all kinds of accessories for thousands of years. Hundreds of bronze sculptures have been unearthed and displaced in many museums all over the world. It’s their thick layer of patina that preserved them for so long, some of them are still intact and need little polishing to look their best again.

Unfortunately, it might cost you a fortune to have any of these artifacts displayed in your own house. The good news is that these are not the only bronze sculptures available out there. There are bronze sculptures that, despite being created more recently, have almost the same distinct color and shade as those of the ancient artifacts. You may wonder how those who made them were able to achieve that. Well, the secret is to speed up corrosion.


How to Speed Up Bronze’s Corrosion

It’s actually no secret that bronze’s beautiful patina can be expedited. In fact, the technique called “intentional patination” became so popular that it has created a whole new industry. It involves exposing bronze to a variety of chemicals until the desired color and shade are achieved. The process is quite simple; anyone can try it at home if they don’t want to spend a lot on purchasing an already patinated bronze furniture or sculpture.

All you have to do is prepare your bronze sculpture by cleaning its surface and making sure it is free from any foreign elements that might get in the reactant’s way. Ferric nitrate is the safest and most cost-efficient choice for a reactant. However, direct application on bronze can cause rapid reaction, which is why it is advisable to apply an undercoat of bismuth nitrate.

The corrosion is usually aided by change in temperature, and so it is important to heat the bronze while applying the ferric nitrate. After covering the entire surface, start applying cupric nitrate to add complexity. Let the coating sit overnight and then wax the surface for finishing. The wax serves as a shield to preserve the color of the patina you’ve forced to come out.


Copper Supplies from the Right Supplier

If you are planning on a project that involves the use of copper alloys, particularly bronze bars, make sure you will get your materials from a trusted supplier, such as Rotax Metals. This is the only way to ensure that you will be able to achieve the right patina for your bronze. Whether it’s a simple bronze or a special one like Muntz metal, it helps you get it from the right source.



The Artificial Patination of Bronze Sculpture, vam.ac.uk
What Is Patina?, thebalance.com
Patina Formulas for Brass, Bronze and Copper, sciencecompany.com

Bronze Bars and Brass Channels: The Evolution of Copper

evolution of copper

Copper is a major driver of trade, so much so that it has long been used to determine or predict the status of global economy. With telecommunication, transportation, and construction taking a new height, demand for copper is expected to go up as well. One apparent reason for this is that there’s no other metal that can substitute copper or any of its alloys. So it’s safe to say that the metal will not be obsolete anytime soon.

The term copper, when used for economic purposes, represents all products that has copper as the base material. In truth, there are quite many copper alloys that have established themselves well to a point of creating whole new industries. Each of these alloys come in a variety of types of their own and with a set of unique properties that are useful for so many applications. Copper in its pure form, however, has its own valuable properties and benefited industries to boot.



Archaeological finds have long proven that copper is the first metal discovered and utilized by man. Its first practical application dates back 10,000 years. After several millennia of experiment, ancient metallurgists found out about the many unique properties of copper and put them to good use. Some of these properties are malleability and ductility, which makes copper the staple material for weapon, jewelry, and cookware making.

Today, copper is utilized for many of its other properties. Electrical wires and most electronic components are made of copper thanks to the metal’s high electrical and thermal conductivity. It also exhibits antimicrobial properties, and so many water filtration and conveyance systems are made of copper as well.



When copper is combined with zinc, a gold-like metal called brass is produced. It’s resemblance with gold is so striking you can easily mistake it for the latter in any given situation. Those who are into gold-based interior design or architecture can save a significant amount of money by using brass instead of the real thing. Nonetheless, the color as well as the properties may change by increasing or reducing the amount of zinc in the alloy.

Perhaps the most popular application of brass is the manufacture of musical instruments. In fact, an entire family of musical instruments is named after it. Compared to other metals, it produces the best sound. Apart from having an amazing acoustic property, brass is also prized for its machinability, making it a good material for various types of machine parts.



One of the most widely held metals in history, bronze is actually just an alloy of copper. It is produced by combining copper and tin. Like brass, this combination also results in a material that has a good acoustic property, although bronze is often used for making bells instead of other musical instruments. Other elements, such as arsenic, phosphorus, aluminum, and silicon, are sometimes added to produce other versions of bronze to be utilized for special applications.

Bronze plays a crucial role in the design and construction of heavy machinery. Because it exhibits low friction and does not spark when struck against other metals, it is suitable for making gear and bearing. Of course, sculptures all around the world relish bronze’s amazing ability to expand while solidifying from a liquid state. This makes the metal easy to carve and press.

Now that you have basic knowledge of copper and two of its best alloys, it will be much easier for you to shop around for the materials you need for your project. Whether you need bronze bars and brass channel suppliers, you can get the highest quality from a reputable supplier like Rotax Metals. They specialize in copper supplies.



Copper: Preliminary Data for July 2017, ICSG.org
Learn About the Common Uses of Copper, TheBalance.com

Different Extrusion Methods—The Making of Bronze and Brass Extrusions

extrusion methods

Metals have been part of man’s daily life since the ancient times. Today, it’s present everywhere from within the pavement you’re walking on to the electronics inside the computer you are reading this article from. It’s hard to imagine a world without metal. Most people, however, know little about how these metals emerged in the first place, where they came from, and how they were manufactured.

There are a number of methods for manufacturing metal supplies. The oldest and still practiced today is casting. It involves melting and purifying metal and pouring it into a mold. As demands for metal evolve year after year so is metalworking. New techniques with higher efficiency and better results have emerged. One of these new and more efficient techniques is extrusion.


What is extrusion?

Extrusion is a metalworking technique that involves the application of high pressure on a metal billet through a die that has a smaller opening and a differently-shaped cross-section. The die is made of a metal that is harder and tougher than the metal to be extruded through it to ensure that it will remain unchanged whether the process is cold or hot working.


Types of Extrusion

Many builders and artisans prefer extrusion for a number of reasons. It produces top surface quality and precision, and it is much faster than other metalworking techniques. To meet even more definitive and intricate specifications, extrusion has been developed into different specifications. Here are the different types of extrusion still practiced today.

  • Cold Extrusion. When extrusion is performed while the metal billet is at room or near room temperature, the process is called cold extrusion. Because the metal billet hasn’t undergone severe chemical change, the resulting material is expected to have not experienced oxidation, has high strength, closer tolerances, and better surface finish. Materials that are commonly cold extruded include copper, aluminum, and steel. The best examples of products of cold extrusion are collapsible tubes, fire extinguisher cases, shock absorber cylinders, and gear blanks.
  • Hot Extrusion. When extrusion is performed while the billet is about its recrystallization temperature, the process is called hot extrusion. At this temperature, the metal is no longer solid and is easier to push through the die. Unfortunately, because the billet is soft, it requires proper treatment to accurately achieve the desired shape and cross-section. One disadvantage of hot worked metal is that it may not be as compact as cold worked metals.
  • Warm Extrusion. Heating the metal at a temperature halfway between the room temperature and recrystallization point produces extrusion of satisfying quality. This type of extrusion is called warm extrusion. This method could work for both ferrous and non-ferrous metals. Products of warm extrusion are expected to have proper balance of toughness and ductility.

If you go to your local metal supply store, you’ll find tubes and pipes of unconventional cross-sections and shapes. These are most likely products of extrusion. Not all metal extrusions, however, have the same quality. Those offered by top suppliers like Rotax Metals are very likely to be of the most desirable quality. So if you are looking to purchase brass extrusions or even bronze bars, make sure to turn to the right supplier.




Metal Extrusion, thelibraryofmanufacturing.com

Product categories