by Professor String

The Five Things You Must Know About Coated Guitar Strings

Perhaps the largest emerging market in guitar strings continues to be coated strings. The coated guitar string is still new to many players, and yet widely used. We are going to take a closer look at this type of string and touch on some subjects that rarely get mentioned about this specialty string.

What exactly is a coated guitar string? It is a guitar (or bass) string that has been treated with a polymer coating. The polymer is often a Teflon PFT (Polytetrafluoroethylene). Typically the wound strings are coated. The polymer coating was originally developed to prevent string corrosion. Specifically, highly corrosive strings such as bronze acoustic strings are almost impossible to keep fresh sounding without a protective polymer layer. By keeping the alloy oxygen free, the strings can sound fresh out of the box for months. Whereas uncoated bronze strings can sound dead after a much shorter duration of time (sometimes just days!). In some regards, the coated string has pumped a little more life into the acoustic guitar market. It used to be a real problem for music stores to carry expensive acoustic guitars, left on the wall for a few weeks with bronze strings, only to sound completely dead. The strings would corrode as the guitar hung on the wall. How difficult is it to sell an expensive dead sounding acoustic guitar? It is not easy.

The polymer coating allows string manufacturers to claim reduced finger squeak, reduced fret wear, and better tuning capability. It also gives them the ability to apply colored polymer to achieve the appearance of colored strings. More recently, some string companies have introduced copper into their alloy mixes. This has historically been a problem, but the coating can prevent the copper from corroding prematurely. Upon reading about all the marketing surrounding coated strings, one could be convinced into thinking..."This is the best thing since buttered bread!"...okay maybe not. But there is a lot of hype and buzz driving the coated string market.

Applying the polymer coating is not a simple process. The trick is getting a very thin microscopic layer of polymer uniformly across the entire length of a string. It requires special equipment and careful quality control. There is a real balancing act to be performed for a coated string to be premium quality. There are some strings with excellent polymer coating, but the metal string itself is poor quality. Yet, there are some strings that have a very poor polymer coating, but the metal string is well made. How does this happen? String companies are not polymer experts, and polymer resin companies are not string experts. A string manufacturer that is able to bring these two disciplines together is the winner.

Here are five things to consider when selecting coated guitar strings:
1. Coating Thickness - The amount of polymer thickness applied to the string will have a direct effect on the string's sound. Do not buy into the hype and claims of the polymer not affecting tone. It is simple physics: String mass is proportional to tonal frequency. Thinner coatings are more transparent to tonal changes than thicker coatings. However, there is a price to be paid. The thinner coating is more likely to wear away faster.

2. String Construction - This is important! If possible, try to understand how the string was coated. Was the string coated after being wound? Was the wrap wire coated prior to winding? Was the core wire coated? I did some consulting with a polymer coating company looking to coat strings for a string manufacturer. The coating company was advocating shipping spools of coated bare music wire to the string company. This made it more profitable and easier to manufacture by processing bulk wire with a coating to the string manufacturer. Likewise, the string company thought it would also help their bottom line by not having to send finished strings to the polymer company. They would simply wind the coated wire and ship it out. Executives from both companies were eager to a get a new product out to market. Going against my advice and some of their testing, the decision was made, and the product went to market. Customers bought the strings at a premium price...and did not like them. The Web was filled with poor reviews as players vented about the strings sounding worse than the old set they replaced. The strings were soon discontinued. So what was the problem with these strings? Answer: The core wire could not couple to the wrap wire due to the coating. It resulted in a loss of sustain and tone. There is something to be said in the difference between strings coated BEFORE winding versus strings that have been coated AFTER winding. Your ears will notice the difference. Take the time to try different sets as not every manufacturer uses the same coating process.

3. Adhesion - It is important that the polymer adhere to the string. It is normal to gradually wear away with hours of strumming. Once the polymer wears away, the string will start to corrode and lose that clean sparkle. In our lab, when we do accelerated benchmark testing, we gently take some 320 grit paper up and down a string to see how the polymer will wear away. Some strings have the polymer come right off after a single stroke. Yet, others will take numerous strokes before the polymer starts to come off in large sections.

4. Application - As mentioned earlier, the acoustic market has benefited greatly from string coatings. Bronze, Phosphor Bronze, and Brass strings are something to consider for coating as they corrode so quickly. However, the need for coated electric guitar strings is still undetermined. The corrosion factor is simply not as high as their acoustic counterparts. Electric guitar strings have leveraged less corrosive alloys such as stainless steel and used tin platings to prevent corrosion.

5. Friction - One of the advertised advantages of string coatings is their ability to reduce finger squeak. The good news is polymer coated strings do reduce finger squeak. Unfortunately, there is another problem that arises with this anti-squeak characteristic: Slippery strings. Remember, the coating is, a Teflon polymer...think of no-stick cooking pans. A very similar polymer. Some coated strings are downright difficult to bend without slipping out from your finger tips. The absence of string friction can be a problem for some players. Since practically nothing sticks to Teflon, there is nothing that can be applied to the strings to increase friction. Again, string coatings vary from manufacturer to manufacturer. Get to know which one has a coating that works best to your liking.

As you become more experienced with coated strings, you will soon start to see the traits that will work best for your situation. When it comes to coated guitar strings, it is no longer about the metallic string itself. It is also about the polymer component. It plays such an important role in sound, feel, and expense.

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