Brass is an alloy, made from two of the more expressive metallic elements on the periodic table: Zinc and Copper. An alloy is a metal made by combining two or more metallic elements. The two most common alloys are brass and bronze. Brass is a mixture of copper and zinc, while bronze is an alloy of copper and tin. We create in order to capitalize on the strengths of different metals. In this case, the combination of zinc and copper makes a rather hardy metal that is more malleable than either of its two parental units. Malleability is a measure of a metal’s ability to be hammered or pressed permanently out of shape without cracking or breaking.
Because it is made from copper and zinc, it takes on the colorful qualities of both metals. Zinc and copper, unlike stainless steel, respond to the environment. Over time they take color from the air, and any spills that happen to grace their surfaces. The same is true for brass. With most coffee tables you want something that doesn’t show any stains, but in this case we’re specifically crafting a stained and “ruined” top.
Because of brass’ high copper content, it is uniquely germicidal. Brass kills microorganisms within a few minutes, to a few hours of contact. Brass has been used since nearly the dawn of our species, though it wasn’t understood as an alloy until the post medieval period. Evidence of the metal begins to appear in the 5th century BC, and then steadily increases in presence. By the time we reach the Roman empire it is being used for artistic expression in bowls, vases, decanters, and sculptures. But brass isn’t unique to one country. It can be found in archeological sites in nearly every continent.
For many people a stained counter top can be ugly, but for our purposes we’re building a coffee table out of brass to tell a story. This table will show rings from cups left too long, discoloration from salt spilled, and striations from greasy fingers. Brass tables leave you with a tarnished tapestry of your nights gathered around, singing, and eating. A note on the difference between tarnish and rust. Rust is destructive, tarnish is protective. Rust will eventually destroy your metal, but tarnish is self limiting. It appears black or dull gray in color but only affects the top few layers of metal. It essentially seals and protects the remaining metal from any damage.
Over time that tarnish blends together and forms what we call patina. I’ve advanced the staining of this table top by leaving glasses out and spraying it with vinegar so that we can show you what patina begins to look like.