Casein Pens: Most Aren't 
Casein was used for pens. But casein pens are much rarer than is generally appreciated, and most pens commonly believed to be of casein are in fact made of ordinary celluloid. This includes the well-known series of bright red Sheaffer Secretary and loaner pens, the latter in both flat-top and Balance configurations. Although many references state that these pens are of casein, this is demonstrably wrong. Even such reliable authors as Fischler and Schneider err in this respect.
What must be borne in mind is that casein was adopted for pens in the 'teens because it could be colored; and with the advent of celluloid, a superior material in all respects, casein became obsolete. Pens made of casein (American pens, at least) are artifacts of the hard rubber era, and are exceedingly rare. The examples one is most likely to see are Parker's Ivorines (button-fillers of the Jack Knife Safety series, in various solid colors), and the odd Conway Stewart. More common is casein trim on an otherwise plain hard rubber pen: Dunn pump-handles and Moore color bands are examples; also the older Mont Blanc stars.
So why do so many knowledgeable pen collectors maintain that any bright red pen must be made of casein? Because Walter A. Sheaffer, in his memoirs, recounts how his firm produced a line of colored casein pens which proved quite popular until the weather turned hot, whereupon the casein swelled to the point that the sections fell out (I suspect the swelling had less to do with the heat than with the humidity of a Midwestern summer). The pens had to be exchanged, and Sheaffer states that they were subsequently recycled as loaners presumably for cool weather use.
I don't know of any pens that can be associated with this account. Every loaner pen I've ever seen has been of celluloid, and I've never seen a casein Sheaffer larger than a Pygmy which is rather too small to serve as a practical loaner. Nonetheless, collectors have long blindly presumed that any Sheaffer loaner must be of casein, and by extension, any pen made of the Sheaffer loaners' distinctive red plastic must be of casein, too. This has led to absurd conclusions, such as the claim that red loaner Balance pens of the '30s ten years into the celluloid era are casein. And recently I have heard it claimed that casein is the material used for those bright red Esterbrook purse-pens injection-molded products of the post-celluloid era! Where will it stop? Perhaps someone will now assert that the recent OMAS Ferrari limited edition is of casein as well.
Myths die hard. Collectors will undoubtedly continue to swear up and down that their cherry-red Sheaffers are casein, even if others' aren't. I did too, until I was challenged to start testing materials for myself. Now I know what casein pens really look like. Finding them, though, is quite another problem. . . .
Addendum: casein was used much more extensively in the UK and Europe than in the USA. In many cases, it is difficult to tell whether a brightly colored marbled pen is casein or celluloid, so when dealing with pens other than American, it is all the more important that they not be soaked indiscriminately.
Copyright © 1999 David Nishimura. All rights reserved