We live in a metal-dependent world. While our ancestors could have done well with just wood and stone, it is after they discovered metals that the human race was able to ascend to the top of the food chain. Metals have since become the backbone of industrialization. And it’s going to take a while before we find equally efficient alternatives to metals.

If you make a list of typical household items that are made of metal or have metallic parts, you are in for a big surprise. In your kitchen alone, you’ll find dozens of them: fridge, stove, sink, faucet, cookware, and even the nails and hinges that keep your cabinets from falling apart – they are all made of metals. You will also notice that many of them have flat and thin structures, including the casing of your stove or fridge, your sink, and many of you cookware.

Are you curious to know how these sheet metals end up being components of those household items? Would you like to take a peek at the manufacturing process? If you’ve ever been to a copper sheet supplier before, you probably have an idea of how these items first looked like before fabrication.

What is sheet metal fabrication?

Before catching a glimpse of the sheet metal fabrication process, let’s first take a further step back to know where the raw materials used in this process come from. Knowing the origin of these materials helps us get a sense of the immensity of work involved in manufacturing familiar metallic products.

All metals turned into industrial supplies start out as ores. Every day, thousands of tons of ores are being extracted in mines around the world. These ores are transported to smelting facilities where they are processed to separate the metals from the dregs. The collected metals then sent to foundries where they are melted and cast into blocks or plates of different shapes and sizes. Some foundries produce finished products, while others produce raw materials that need further work. And that’s where sheet metal fabrication comes in.

Sheet metal fabrication is a subset of metal fabrication that focuses on sheet metal. It’s the multifaceted process of creating metal structures out of sheet metals. It starts with flattening raw metals to a specific thickness and breadth through rolling, pressing, or hammering. Once the metal sheet or plate is ready, it goes through any of the following methods, depending on the desired output.

• Cutting

  Possibly the most common of all processes involved in sheet metal fabrication, cutting produces metal pieces of precise dimensions, divide large sheets into several parts, and create accurate perforations. You can cut sheet metals manually using power tools or with laser cutters.

• Blanking

  This cutting method involves cutting out a portion of the sheet metal based on a stencil. The excess material is discarded or recycled.

• Bending

  Depending on the design, you may need to ben portions of the sheet metal cuts you’ve made. You can do this using press brakes and other tools. Large sheet metal suppliers like Rotax Metals use heavy-duty, cutting-edge equipment for bending metals parts.

• Galvanizing

  To increase sheet metals’ corrosion resistance, their surfaces are coated with zinc. A good example of galvanized sheet metal is corrugated metal roofing panels. The zinc coating works effectively in prolonging the life of your roof.

• Milling

  If the metal piece is still too thick and further reducing its thickness through rolling or stretching is impractical, milling is the next best course of action. It requires the use of a rotary cutter.

• Shrinking

  Sometimes, the finished product has small dents on its surface that count as a defect. You can get rid of these dents by heating and stretching the metal piece a little bit until all of the dips disappear.

Types of Sheet Metal

Any metal with a considerable level of malleability can be transformed into thin sheets or plates and eventually fabricated through the previously mentioned processes. Tough and rigid metals are often combined with soft metals to produce malleable but strong alloys. Below are some of the common types of sheet metals.

• Copper

  One of the most extensively used metals, copper possesses many valuable properties. Malleability is one of them, which is why copper is often cold-worked. Copper is also known for its high corrosion resistance, electrical conductivity, recyclability, and antimicrobial property. It combines well with other metals, too.

• Brass

  An alloy of copper and zinc, brass is also extremely malleable. It’s no wonder many metallic products that consist of tubes and plates, such as musical instruments and cookware, are made of brass. This metal is famous for its gold-like appearance, but you can produce different colors of brass by changing its content proportions.

• Bronze

  Another alloy of copper alloy, bronze is made of copper and tin. Both are corrosion resistance and extremely malleable, which is why bronze is a perfect material for a lot of machine parts and vehicle body. Many ships have bodies made of unique types of bronze.

• Stainless Steel

  This metal comes in a vast array of grades. Like copper and its alloys, stainless steel is also corrosion-resistant even though it contains iron. The most common types of stainless steel are austenitic stainless steel (containing chromium and nickel), ferritic stainless steel (containing high levels of chromium but little nickel), and martensitic (does not contain nickel).

• Aluminum

  There are many reasons why aluminum is a popular choice in both manufacturing and construction. For one, it’s corrosion-resistant like the previously mentioned metals. It also has an outstanding strength to weight ratio. And perhaps the most recognizable feature of this metal is its abundance. Aluminum is one of the most abundant elements on Earth.

Knowing which metals are malleable allows you to choose the right material for your sheet metal fabrication projects. Of course, each of these metals is available in different grades. To be sure which grade will work best for your projects, consult with expert brass suppliers. Explain the nuts and bolts of your project, and they can tell you the right type and grade of metal to use.

Over 80 percent of all known elements are metals. Experts classify them according to their physical and chemical properties, such as density, conductivity, melting point, and reaction to certain chemicals. Arguably, one of the simplest ways to classify metals is through their decomposition.

Like any other material, metals decompose when exposed to another element or compound. We call this process corrosion. While all metals corrode, some have higher corrosion resistance than others. In most cases, different metals corrode differently when exposed to the same chemical. For instance, iron turns into rust and zinc turns into a white powder when they come into contact with air or moisture.

In terms of corrosion, there are two broad classifications of metals – ferrous and non-ferrous. Ferrous metals contain iron, while non-ferrous metals do not. Iron is particularly notorious for being susceptible to corrosion. Oxygen is its main catalyst. When exposed to any oxygen-containing substance, such as air or water, oxygen atoms from that substance combine with iron atoms and form iron oxide or rust.

Does copper rust?

Copper is a non-ferrous metal. It doesn’t contain iron, so it won’t turn into rust when exposed to oxygen. Instead, when oxygen molecules land on copper’s surface, they combine with copper atoms and form copper oxide.

Unlike iron oxide, copper oxide does not disintegrate over time. It stays on copper’s surface and gradually thickens until it becomes copper carbonate. This new layer of material, commonly known in the metal world as patina, serves as a shield against the elements, preserving the unspoiled copper inside for a very long time.

The Pros and Cons of Copper Corrosion

Generally, corrosion is considered detrimental to metals because it takes away their useful properties. For instance, rust causes iron to lose its tensile strength, rendering it useless for construction applications as a result.

Corrosion of copper metal, on the other hand, is different. Instead of destroying the metal, it gives it an elegant and unique appearance. Furthermore, it doesn’t diminish copper’s key properties, such as workability and conductivity. If anything, the outer covering produced from corrosion gives copper added protection, allowing it to last for millennia.

Copper Alloys and the Effects of Corrosion

Copper is among the most flexible metals around. It can easily bend and stretch due to its high malleability and ductility. Unlike other metals, copper is an excellent base material for alloys to boot. Of the many different copper alloys available today, the most popular are brass (copper and zinc) and bronze (copper and tin).

To produce different versions of these alloys, metallurgists alter their content proportion. They add a miniscule amount of other metals (sometimes non-metals) into the mixture to create more variations.

Because copper alloys contain other metals, they corrode differently from how pure copper corrodes. For example, most types of brass turn golden brown during the final stage of corrosion, while copper turns green. In fact, one can tell how long copper or its alloys have been corroding by their color. This gives artisans a wealth of choices when decorating with copper-based sculptures and fixtures.

Then again, some applications require copper or its alloys to be in their pristine state. Copper-based machine components such as copper rods and plates, as an example, work optimally when their surfaces are free of patina. The same goes for copper wires; they are most electrically conductive in their purest form.

Copper corrosion is a slow process, so it’s easy to preserve the sheen of a copper, brass, or bronze item. In fact, it takes decades for copper to develop a greenish top layer. In addition, all it takes to polish these metals is an over-the-counter metal polish or homemade mix and a clean cloth. Some copper alloys, however, tarnish fast, so you have to polish them more often.

Forcing Copper Corrosion

As previously mentioned, copper corrodes very slowly. It only begins to change color after months or years of exposure to air and moisture. You may wonder how architects and interior designers are able to find copper fixtures and furniture pieces with the exact shade and color they need for their projects in a short span of time.

There’s no way they’ve been waiting for those items to patinate prior to their project’s commencement. What they actually do is force copper to corrode by applying certain chemicals on its surface. Oxygen is not the only element that can cause patina to form on copper’s surface. A lot of other harsher compounds are actually more effective, turning copper from red to brown in a matter of minutes.

Here are some of the popular methods for creating patina on copper items:

1. Incubate the item with hot crushed boiled eggs.

   After boiling a few pieces of eggs, place and crush them in a sealable plastic bag. Bury the metal piece into the crushed egg and let it sit for 30 minutes to an hour. To achieve a dark shade of patina, incubate the metal piece for several hours.

2. Spray or apply a vinegar-salt solution on your copper item.

   Both vinegar and salt are potent enough to accelerate the formation of patina on copper. With the right mixture, it can even give your copper item a bluish patina. To get a more specific shade or hue, you can add sawdust and chips into the mixture.

3. Suspend the copper piece in saltwater and non-detergent ammonia vapor.

   Put the mixture in a container with a cap. Find a way to put the copper item in the container without touching the solution. You only need to expose it to the vapor. This means you have to close the container as well.

There are other chemicals that you can use to force corrode copper or its alloys. Ferric nitrate, sodium thiosulfate, and sulfureted potash are the most common. Each of these solutions produce a different patina color on copper. However, other factors such as temperature and humidity may also be at play.

Probably the least noticed but one of the most influential factors is the quality of the metal piece. Even the tiniest impurities within the metal could have a serious effect on patina formation. This is the reason why it’s crucial to only obtain your materials from the right copper sheet supplier. Here in North America, your best option is Rotax Metals. They have nearly a century of experience with copper and its alloys, so you can be sure that they provide the highest quality copper plates, sheets, rods, and anything in between.