The Incredible Changing Pen!

(fig 1.) Nurse Pen with Beautiful Patina. (Author’s Collection)

Recently I acquired a Waterman’s nurse’s pen with a color and patina I had never seen before (fig 1-3).

(fig. 2)
(fig. 3)

Normally these pens were a crackle-ice white color, with an emphasis on white, almost assuredly to match a nurses’s uniform. But this one has delightful caramel colored swirls. I wondered why this might be: was it manufactured that way (unlikely) or had the color changed with age?

It turns out that the latter explanation is the reason for this gorgeous color, and that there is indeed a solid hypothesis for why this pen looks the way it does.

Nurse’s pens are made of celluloid. This material is susceptible to chemical reactions of inks and ink sacs. Let me explain.

Inside this pen is an ink sac, a bladder that holds ink and when squeezed by the lever on the outside of the pen and (fig. 4) draws ink from the bottle and fills the fountain pen.

(fig 4.) The lever that fills the pen

If the sac is made of latex (and the original sac assuredly was) as the chemistry of the ink interacted with the sac and as the sac began to age, it off-gassed and interacted with the celluloid (fig. 5). That, and other environmental factors, is almost assuredly why this pen became the color that it is today. I’ve learned that this phenomenon is known as ambering, and it’s common in pens of the 20s-40s.

(fig. 5) The Interior of an Esterbrook pen, showing a latex sac.

When this pen was restored, the dealer followed best practices and installed a true (non PVC) silicone sac, one that will not off-gas and further compromise the celluloid (fig 6.) (Note that pens re-sacced with silicone sacs should be stored nib up and vertically, since there is a slight chance of oozing ink because of the material of the sac.)

(fig 6.) A Proper Silicone Ink Sac

I know now that it was a combination of reactions that changed the color of this pen, basically making it an accident of time and chemistry. I for one am happy it happened–this pen is unique and gorgeous!

From left to right, you can see how the luck of chemistry and time have changed this pen to a different patina from the other examples in my collection

I do have a question about the bands on this pen. The design is made up of a thinck gold band with a thin one above and below. I’m not certain if this design appeared on Doctor’s Pens, Nurse’s Pen’s, or both. I am assuming this is a Nurse’s Pen, but I am always open to your comments. Contact me!-30-

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