Friday, October 5, 2012

Metal Education - Intro

Welcome to the new Etsy Metal blog series dedicated to metal education.
Our 100+ Etsy Metal team members create incredible art projects, from tiny jewelry to silverware, bowls, and large-scale metal sculptures. What brings us all together is our love for metals.

Wide Mixed Metal Patchwork Cuff Bracelet by Michele Grady Designs Jewelry

We choose the metals we use for specific reasons, including visual appearance, cost, hardness, durability, and resistance to corrosion and oxidation. We think about workability and whether the metal can be used with gemstones, enamels, patinas and paints. In our new Metals Education blog series, Etsy Metal experts will talk metal, from ancient methods to modern alloys. We will describe the uses and characteristics of metals. For our metalsmithing readers, we will share metalworking techniques, tips, and other useful information.

18k Yellow Gold and Sterling Silver Wedding Set with White Diamond By Sarah Hood Jewelry

Metals have been used for thousands of years, first showing up in early hunting tools and personal adornment. While many metals and techniques are still being used the same way today as in ancient times, others have evolved and changed with technology.

 Almost 75% of elements in the periodic table are metals. The elements we use most as metal artists are gold, silver, copper, aluminum, platinum, palladium, rhodium, nickle and iron. Originally, all metals were obtained from mining, but today there is a greater push in the metal arts to use refined and recycled metals, minimizing the negative impact on the environment and ensuring an adequate supply for the future.

Let's talk about a few basic definitions first.

Base Metals, Noble Metals, and Precious Metals:

The chemical term “base metal” refers to a metal that reacts easily with oxygen or other chemicals in the environment. These reactions lead to oxidation or corrosion of the metal and a change in its physical properties over time. Commonly used base metals include copper, lead, nickel, zinc, and iron. Because of their reactivity, many base metals are used to drive essential chemical reactions in living organisms. Iron reacts so strongly with oxygen that it is used in the bloodstream to grab oxygen from air in the lungs.

Handmade Copper Bracelet Etched Paisley Cuff by Karla Wheeler Design

In non-scientific usage, the term “base metal” has also come to mean any metal that is abundant on earth or inexpensive, but excludes iron. Because of their relative abundance and low cost, base metals are especially suited to large-scale projects like buildings and sculpture, but are also often used in small projects and jewelry. In any application, a base metal’s reactivity and tendency to change over time should be considered.

Industrial Steel Desk Organizer by CitiZenoBjeCts

Noble metals are chemically stable and non-reactive; they do not oxidize easily or corrode in moist air. The Noble metals are gold, silver, platinum, palladium, rhodium, ruthenium, osmium, and iridium (some definitions also include mercury and rhenium). Titanium, niobium, and tantalum are not considered noble metals, even though they are resistant to corrosion under normal conditions. They are not noble metals because they are chemically unstable and react readily with acids or halogens (like chlorine and iodine). They become corrosion resistant in the environment because they oxidize rapidly to form a thin protective layer that renders them chemically inert.

Noble metals are rare on earth and more difficult to extract and refine than base metals. Hence, many noble metals are also called “precious metals,” which means they have a high economic value. Though most noble metals are also precious, the “precious” category can change over time as the market value fluctuates with supply and demand.

Redwoods - 14k Rose Gold Tree Bark Rings by Beth Cyr Weddings 

Because noble metals are stable over time and have little tendency to react with the body and the environment, they are the most prized for jewelry. Noble metals are also used where inert metals are needed in industrial and biological applications. However, the high cost and rarity of noble metals is prohibitive. In addition, some noble metals in their pure forms, like silver and gold, are so soft that their usefulness is limited. For these reasons, noble metals are frequently mixed (or alloyed) with base metals to change their working properties.

Metal Structure and Alloys:
When a liquid metal cools into a solid, the metal atoms pack together into crystals. Metals get their working properties, including hardness, density, shear strength, and ductility from the characteristic shape and packing of these crystals. Metal crystals (and hence, the working properties of the metal) can be modified by heat, time, and by hammering, bending, or otherwise deforming the metal.

Most metals used today are not pure, but are alloys. This means they are made from a mixture of a metal (the main component) and something else, either one or more other metals, or a combination of metal and non-metal. Alloying works by altering the crystalline arrangement of metal atoms. When a new substance is introduced to a pure metal, the differing atoms, which might vary greatly in size, must find a way to pack together neatly, creating new crystal packing arrangements. As a result, the physical properties of the new alloy can differ dramatically from the original materials.

Alloys are often created to increase the hardness and strength of a metal. Steel, an alloy of iron and carbon (among other things), is harder than iron. Sterling silver is made harder and more durable than pure silver by adding 7% copper. But there are some drawbacks to alloying. In the case of sterling silver, the added copper does make it tarnish. However, the tarnishing effect is often used to an advantage to add interesting patinas and oxidation to metals.

Stingray Hoops by Revonav

Alloying can also change the color of a metal dramatically, as anyone can see when comparing the lustrous yellow color of pure 24 karat gold to the lighter yellow of 14 karat gold, or to white gold.

22k gold and silver post earrings - bowl of gold by Mary Anne Karren

There are many ancient alloys still in use today, including brass, bronze, steel, and some gold and silver alloys. But manufacturers, suppliers, and metal artists are always trying to improve their alloys and develop new mixes to deal with certain issues.

Browse some mixed metal work our members created: here.

In the coming months, our Metals Education blog series will look into metals and alloys in more depth. We’ll try to cover the basics, history, the uses and working properties of some of the following:

· Fine Silver
· Sterling Silver
· Argentium Silver
· Nickel silver, German Silver
· Copper
· Brass
· Bronze
· Yellow Gold
· White Gold
· Rose Gold
· Green Gold
· Gold filled
· Gold plated
· Palladium
· Silver/Palladium
· Palladium sterling
· Platinum
· Aluminum
· Titanium
· Stainless Steel
· Steel
· Iron
· Cobalt Chrome
· Pewter
· Niobium

So stay tuned for more.

Thanks to Mary Anne Karren for all her help with fact checking and editing.

1 comment:

Anonymous said...

Looking forward to the rest of the series!

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