Kamakura Fountain Pens






Red And Orange Hard Rubber,
rhr pens weren’t red in the first place.

George Kovalenko

A while ago over on Pentrace, they were talking about red and orange hard rubber, and I thought I’d post a version of my response here on Ron Dutcher’s archive, since my post has already disappeared from that message board.

Syd Saperstein is right when he talks about orange hard rubber. Red hard rubber pens weren’t “red in the first place”. They were orange. Well, that’s not always true either. The lighter ones sometimes darken where the cap fits onto the barrel, but they were originally brighter in color. Some people say it’s the other way around, but I don’t buy it.

A red hard rubber Newton Kurtz slide pen and mechanical pencil from the Kovalenko collection
Some batches of rhr have iron oxide, or hematite in them, which makes them brownish red to start off with. It is the pigment most often used in soft elastic rubber. But the major constituent coloring agent of rhr is cinnabar, or vermilion, which is red in color. Chinese and Japanese lacquer are colored with it, and are typically called “red lacquer”. Some other red pigments that were used in rhr are minium, or red lead, and litharge, or yellow lead. In Japan, where cinnabar, minium, and litharge are used as artist’s pigments, it is well documented that the red colors in paintings unpredictably darken and often turn rusty brown over time, so the same kind of thing probably goes on in rhr as well. The red pigments actually revert to black versions of the natural minerals. In the case of cinnabar, the culprit is light. When exposed to light, it turns black. The substance responsible for turning red lead to black is sulphide, and since sulphur is the vulcanizing agent in hard rubber, any rhr that darkens in the absence of light probably contains a high percentage of minium or litharge.

In order to make the rhr brighter in color, scarlet antimony and golden antimony were added to the mix, as well as other yellow pigments. Black and white pigments were also very important in attaining the right shades. I’ve seen a lot of early formulas and recipes for rhr, and they all contained these pigments to various degrees. These deadly heavy-metal pigments are no longer allowed for safety reasons, and the contemporary substitutes just don’t cut it. That’s why Chris Thompson is having such a hard time approximating the old color in the red rod stock he is having made for him. Parker used a synthetic dye in the middle and late rhr Duofolds called Vulcafor Orange, which made the rod stock lighter in weight as well as in color. It is why those later rhr Duofolds look so glorious.

Some companies had their own supplies of rhr, and their own proprietary formulas for their distinctive shades of red rod stock. Sheaffer red is much darker than Parker Duofold red, and Wahl Eversharp red is almost a creamy coral. The brightest oranges are the Onotos and the Conway Stewarts and the Duofolds, but then I’ve seen darker ones as well. There’s no general rule. Sometimes Waterman’s red is light, and sometimes it’s dark. It’s highly unpredictable and very infuriating. Some of the early Parker rhr is slightly darker, but the Vulcafor Orange Duofolds make up for it. After those glorious rhr Duofolds, the red plastic ones are a huge disappointment.

23 Dec 2004



Modern Red Hard Rubber, a bright orange rhr.

Over on Zoss, Glenn Craig asked whether any brave new company is working on a modern red hard rubber. Well, the only things holding it back are economics, and in the US, the further complication of safety standards.

Let’s start with the safety issues. David Broadwell is right on this point. The old red hard rubber formulas incorporated not only mercury in the form of the mineral vermillion, or cinnabar, but also minium, or red lead, and litharge, or yellow lead, and golden and scarlet antimony. All these heavy metals are highly regulated and restricted in the workplace today, and that makes the old formulations of yesterday impossible.
There are at least two companies in the US that could make red hard rubber, but they won’t use these old colorants. Chris Thompson is working with one of these companies to try to develop a rhr rod stock, but this is exactly the problem that he has run up against. He has a darker shade of rhr, but not the desired brighter orange tint. Also, the developmental costs of experimenting with trying to achieve that brighter color are quite high, so if he does succeed, the rodstock won’t be cheap.

There are also three European companies that make hard rubber, one in Germany, and two in Italy. The German company, New York-Hamburger Gummi-Waaren Compagnie, is based in Hamburg, and it’s been in the trade since the 1870s.


They also make the darker shade of rhr, but there’s another problem. A few years ago, the minimum order used to be 1000 meters of rodstock. Now, the minimum order is about 50 to 100 meters, but that might still be too much for some penmakers. All pen repairmen could use a few meters at least, and pensmiths such as Paul Rossi and Michael Fultz could make use of a few dozen meters or more, and some small pen companies could utilize a hundred meters or so, and even I could use a few meters. Perhaps we’ll have to get together a red hard rubber cartel.

But that still doesn’t solve the problem of the color. Some might want a darker shade to repair older pens, and others might want the orange shade more common in the 1920s, to repair Duofolds and Watermans and the like. It might not be possible to please everyone, and the cartel will fall apart.

There might be a solution, though. In 1992, “Pen World” published a series of articles by Bob Tefft on “Materials Used To Make Pens”. In one of them, he gave the formula for the rhr used in the later hard rubber Parker Duofolds. The early Parker rhr contained the usual heavy metals, but the rhr from the later-Duofold era substituted a synthetic aniline dye called Vulcafor Orange. That’s the secret of those glorious orange later hard rubber Duofolds. The dye goes under about 50 different trademarked names, depending upon which company makes it. These names include “Tiger Orange”, “Pyrotone Red”, “Pigment Scarlet”, “Tanager Red”, “Blazing Red”, “Flaming Red”, “Fast Orange”, and “American vermilion”, all

1920's Namiki red hard rubber fountain pen from the Kovalenko collection

commercial names for chlorparanitraniline red, otherwise known by the chemical names, 2 - Naphtalenol, 1 - ((2 - chloro - 4 - nitrophenyl) azo), and
1 - ((2 - Chloro - 4 - nitrophenyl) azo) - 2 – naphthol.
Perhaps someone can be persuaded to take it upon himself, or herself to get in touch with Anselmo Volonta, the Italian company producing hard rubber rodstock for fountain pens that Giovanni Abrate mentioned, to see whether a special formulation using Vulcafor Orange would be possible. Then it’s just a matter of getting the cartel together.

14 Feb 2005