It's all about ions and oxides when it comes to solid metals and parts made of brass. Kowaluska Clay Pigeon Coasters are made from a solid bar of 360 series brass. If you haven't had the opportunity to feel one of the Clay Pigeons, they are heavy, surprisingly so. The next questions might be, why is Kowaluska making products from brass? Aren’t Kowaluska pieces aerospace grade? Aren't airplanes supposed to be lightweight? Yes- but they also must be durable, tough, and able to operate in the harshest environments. Brass is used for aircraft in a few key areas; fittings, bushings, and bearings. Brass is easily machinable, and it is also soft enough that a seal can be made between two metallic components without needing any rubber or other elastomeric seals. The benefit of this is that the sealing joint between two metals can withstand substantially higher temperatures than using a rubberized seal.
The other area brass is widely used in is bearings and bushings; where a very tough and corrosion resistant material is needed but it must also be soft enough to not wear out the moving components. You will often find brass components in the wheel and brake parts of many aircraft. Brass is a mixture of copper and zinc mixed to form a new alloy. Zinc by itself is highly corrosion resistant. The process of galvanizing is simply coating steel with a thin layer of zinc to make it more corrosion resistant. Copper is also, by itself, corrosion resistant. Copper has been used for everything from pennies to roofing to the Statue of Liberty and can last for generations exposed to the elements.
Now, about those oxides. With all the highly beneficial properties of brass, comes the reality that new brass will age and develop a patina over time if left to its own devices. Since brass is mostly copper, the copper part of the alloy will react with oxygen to create a copper oxide layer on the surface. This layer of copper oxide is what most people would call a patina. The brass will darken and take on a green, brown, or reddish patina, it isn't rust, it's a hard layer of an actual different substance that further adds to the corrosion and wear resistance of the base material.
At Kowaluska, we venture to create the best of both quality and beauty. Here is where the ions come in. Through some endurance testing (a few cocktails with friends and family using both the OurGlass and Clay Pigeons, then somehow forgetting to do dishes) we found that with prolonged contact between the OurGlass tumblers and the Clay Pigeon coasters, that some dark discoloring occurred. This discoloration is due to ions. The discoloration was beyond what a normal patina would look like and the flashbacks of what not to do in engineering school began to replay. If you are already bored by the techy stuff here, just skip to the next paragraph. Really, no offense taken. If not, the basic premise is that two metals that aren’t the same metal really don’t like each other. All metals have a range of whether they are anodic (positive) or cathodic (negative). When metals that are too opposite on the scale are put next to each other in the presence of any electrolyte, which could be water, wine, juice, etc… accelerated corrosion will occur. Galvanic corrosion is the term for this type of corrosion, and yes, it comes right back to the oxides. Water is normally present and different ions from the more active metal form hydroxides and will corrode the material until there is no more water or the two metals are no longer in contact.
Part of the product development and engineering process is to continually improve. At Kowaluska we only accept the highest quality. Therefore, we explored a few options and decided to enlist the help of a team that maintains and prevents corrosion on the exterior of aircraft. On the base of each Clay Pigeon is a film that is used to prevent abrasion and acid damage from bugs and other debris on the surface of aircraft. Aside from being scratch resistant, water resistant, and completely transparent, it also creates a separation between the Clay Pigeon and any cup or glass. It doesn’t matter what the material is (glass, aluminum, steel, or crystal), it will prevent any corrosion. All Clay Pigeons are also sealed with an aircraft grade ceramic coating that binds to the surface of the metal and helps to prevent oxygen from reacting with the base material. Combined, both processes will ensure the longevity of your Clay Pigeons- even if you forget to do the dishes after a night well spent.
Until next departure,
Matt