Despite its superb corrosion resistance, brass tarnishes considerably fast. It can lose its original luster within hours after being exposed to moisture, or even just to air. Thankfully, the tarnish on brass can be removed just as fast with proper polishing. But before we teach you how to bring your brass items back to its shiny self, let us first get to know brass more.
What is brass?
When we think of brass, the first thing most of us would imagine is a musical instrument, such as a trumpet or a trombone. That’s because brass instruments are perhaps the most famous types of objects made of brass. Very few have a clue that brass extrusions, bars, and tubes are also very common. This is a metal that consists of copper and zinc. Sometimes, a minute quantity of other elements, such as arsenic, lead, phosphorus, aluminum, manganese, or silicon, are added to improve its properties.
Brass owes its corrosion resistance from its copper content, although zinc is itself corrosion resistant. Like copper, brass slowly forms a patina on its surface when exposed to the elements, as opposed to other metals, particularly the ferrous ones, that form rust instead. A patina is a thin layer of material that develops as a reaction of copper molecules on the surface of brass when they make contact with oxygen molecules.
Unfortunately, not everyone is attracted to the rustic appeal of patina. While some want their brass items looking elegantly antiquated, others want to keep them shiny at all times. The initial process of patination is characterized by the formation of tarnish, so those who dislike patination should deal with it when it’s just in the form of tarnish. Unsurprisingly, tarnish is much easier to remove than a full-grown layer of patina.
How does tarnish form?
As mentioned, tarnish is undeveloped patina, but how does it really form? The best way to find out is to put a piece of brass under an electron microscope and observe how its molecules interact with the air or with any other object or substance placed on its surface.
When copper and zinc are combined, they form a rather unique assembly of molecules. The atoms comprising these molecules share valence electrons with one another. Those that have already lost their valence electrons become ions, and they are the ones responsible for the formation of tarnish. When ions of brass interact with ions of moisture or air, a layer of chemical compounds that have a different color from the metal itself emerges. Occurring in stages, this layer starts out as dull tan and leads to dark gray, blue, or green. Let me give you some good tarnished brass cleaning tips.
How do you get tarnish off brass?
As previously explained, it is easier to remove patina during its early stages, specifically when it’s just in the form of tarnish, so it shouldn’t be difficult to clean your brass item at this point. There are two ways to go about it—naturally, using natural and everyday products, and with the aid of chemicals. Regardless of your preferred agent for cleaning tarnished brass, however, here’s what you should do to get tarnish off your brass items.
Step # 1: Make sure it’s really brass.
Brass is often used for decoration because it resembles gold. This mimicking feature is not unique to brass, though, because other metals can look the same as brass with the right alloying or coating. If you’re not careful and you start cleaning your item without making sure it’s really brass, you might damage it with the chemicals you bought. To determine whether or not your item is really brass, hold a magnet to it. Brass is not magnetic so if the magnet sticks, your item is not brass and may need a different polishing approach. Ironically, if your item isn’t brass, you may not even need to polish it because it wouldn’t have tarnish in the first place.
Step # 2: Find out if the item is lacquered or non-lacquered.
Lacquer is a clear coating applied on the surface of metal to give it a protective shiny finish. It’s quite easy to tell whether your item is lacquer-finished or not simply by wiping it with a clean, dry cloth. If the surface immediately turns shiny again, it means it has lacquer on it. That’s because lacquer is meant to preserve the shiny appearance of brass, like a laminate on your windshield. It only turns dull-looking when it’s already cloaked with dust and grime. The reason you should do this test is because you might damage the lacquer with metal polish. Considering that lacquered brass has its shiny surface preserved, polishing it is not a good idea.
Step # 3: Wash the item very carefully.
Before you start scrubbing the surface of your brass item, wash it first to get rid of excess dust and grime. These contaminants may consist of tiny sharp-edged stones that might scratch the surface of your brass item if they get mixed up with the soap suds that you will scrub with the cloth. After rinsing, dry the item very carefully so no trace amount of water will be left on its surface. Water can dilute your metal polish and reduce its potency.
Step # 4: Prepare the polishing agent.
If you opt to polish your brass item using a commercial product, all you need to do is to go to your nearest hardware store and look for one that is neither too harsh nor too mild for your brass item. The supplier would normally know what you need if you give them as much information about your brass item as possible. In case you want to try natural products, that’s where you need to conduct a little chemistry experiment at home.
There are scores of products around the house that you can use as a polishing agent, of which the most widely used is the baking soda – vinegar solution. Other products that contain a little bit of acid, such as ketchup and lemon juice, are also good for polishing. Just make sure you will mix the right amount of each ingredients to avoid making the solution too harsh for your brass item. You don’t want to scuff a significant layer from the surface of your item as you buff it up.
Step # 5: Buff with a clean cloth.
Slowly apply the solution on the surface of your brass item. Make sure every groove and section is covered with the solution, and then wait for it to dry before you start buffing with a clean cloth. As you scrub through the surface, you will notice the dark, old surface slowly disappearing and the shiny layer underneath finally emerging. Don’t stop until the entire surface of your brass item is free of patina.
How to Prevent Tarnish from Forming Again
The truth is, you can’t prevent tarnish from forming, but you can delay its formation. As previously explained, the only way to preserve the shine on brass is to keep the elements at bay, which is quite tricky. You can, of course, apply lacquer, but even this amazing coating would soon succumb to the elements and disappear. What you can do is either to regularly polish your brass items or allow it to patinate.
Brass’s susceptibility to tarnishing may also have to do with its quality. Low-grade brasses usually have lower corrosion resistance than those manufactured by top brass suppliers, such as Rotax Metals. Therefore, it is important that when looking for brass materials to use in your projects, always go to a supplier that runs its own foundry and has been in operation for many decades to make sure of the quality of the products you will purchase.