One of the debates involves the material out of which the feed is manufactured. Old pens, before 1950s, used ebonite (vulcanized hard rubber) and around that time different plastics made their way as the material of choice for feed it is today. Ebonite, though, is still used today on mostly high-end pens and this is often used as a selling argument (however, it might be worth to note that Montblanc’s flagship pen, the 149, implements plastic feeds). Many a stylophile are happy to buy that argument and swear by ebonite as the ultimate material to provide a good (and generous) flow of ink to the nib.
But, is the feed material that important for the final performance of the pen? Or, in other words, what are the differences between these two materials, plastic and ebonite?
The main difference lies in the way the ink interacts with those two surfaces. Ebonite is hygroscopic and favors capillarity and circulation of the ink along the ink channels.
On the other side, ink forms drops on plastic and its flow becomes more difficult. There are some ways to correct this issue: making the surface less smooth (“unpolishing” it) the surface of the channels increase and the ink smears along them. Another strategy was to add some hygroscopic layer to the feed.
But the final conclusion might be that due to that problem –the ink not wetting the plastic feed—ebonite should be the obvious option. However, ebonite carries its own problems to the production line—it is more expensive than plastic and needs to be cut. Ebonite oxidizes in the wrong environment, and its purity (or the presence of impurities in it) plays an important role in the final quality of the manufactured good. The final result is that it is not unusual to see deformed, bended or cracked pieces of ebonite, in feed or in other pen parts.
Section, nib and feed of a Super T Gester from ca 1960. This feed, made of ebonite, was bended and could not drive the ink to the nib efficiently.
Plastic, on the contrary, can be molded into the desired shape, and is very stable chemically. So, plastic is cheap, fast and reliable.
Two plastic feeds by Platinum from the late 1950s. The one on the left was misstreated, whereas the one of the right has never been used. Both preserve the original shape.
Well designed feed, on their side, do work well and are able to provide fairly big flows of ink. Case in point—the Nagahara’s two- and three-fold specialty nibs are attached to plastic (ABS) feeds. There are no complaints in the pen community about their reliability, and they show that a proper design does the job despite the limitations of the material.
Plastic feed of a cross-music nib by nibmeister Nagahara. But in fact, all feeds are the same for a given nib size in the Sailor catalog.
Some may argue that plastic feeds have not passed the test of time and that we cannot really asses whether they might degrade with time. And they go further into saying that we can also find perfectly preserved ebonite feed after many years of use or storage. But we also know –and that is the point here— that ebonite feeds are vulnerable.
After all these considerations personal preferences and romantic ideas come. And they are welcome, for writing with these tools is in itself romantic and anachronic.