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Posts Tagged ‘Aerometric’

Anti-Nausea Treatment

Posted by Dirck on 11 May, 2017

A bonus entry!

In the progress report, I have today’s pen down as the Parker Challenger, but I am in fact carrying a second pen today.  This is not the only transgression of my usual policies, because that second pen is not mine– it belongs to a client.

I am at least as shocked as everyone else.  But it’s done for a noble cause.

The reason this pen is in my clutches at all is because it has been throwing up in its cap.  That’s not good.  It’s also very unusual behaviour for the model.  The Parker “51”, after all, invented having enormous buffers between ink and outside world, and the only thing I could think of was that the owner wasn’t filling it properly… except in discussion with that person, I got a sense of someone who actually knew what was what in the filling of pens.  Like me, they are a user of collected pens, seeing little point in a pen left sitting on a non-marking velvet pillow in a safe-deposit box.  If it wasn’t pilot error, then… what?

Exterior inspection first.  The “51” is well known as being durable, but it’s not Kryptonian.  Might there be a covert crack in the hood?  Careful, well-lit turns under the loupe said no.  And that meant I had to take it apart and look at it’s guts.

There are, of course, two main sorts of “51”.  There is the initial wave, using a Vacumatic filling mechanism, which was swapped out after seven years of production for the Fotofil press-bar rig, which we call today the Aerometric… and actually, this word is of some importance.  It described a breather tube in the very heart of the filler, so long that it reached to nearly the end of the Pliglass sac (oh, so many neologisms out of Parker!).  This allowed the sac to fill fully by working the bar several times, but to avoid catastrophic leakage during air travel, there was a teeny little hole in the side of the tube, close to the open end of the sac that equalizes pressure inside and outside the tube; that’s what was originally meant by “Aerometric”.  This pen has a Fotofil reservoir, and all the other outward signs of being a post-1948 product.

…so imagine my surprise when I opened the pen and found the stubby little breather tube of a Vacumatic filler peeking out the back of the collector.  There was a 1951 date-code on the point, which is entirely appropriate, but the feed and the associated breather were Vacs.  It seems that at some point before the current owner got this pen, something awful happened to the feed.  Whoever had it at that point cast about for a spare, and had only the older Vac type at hand; the breather tube in question was a new plastic item, not the original celluloid, so modern monkeyshines are indicated.  “Oh, well,” said this imaginary repair-person.  “It all fits; where’s the harm?”

Frankly, I don’t really blame my figment, because it took me a while to figure out how the symptoms developed.  That short breather would prevent a complete fill, and I suspect if it had been a little shorter, nothing would have come of it other than the owner occasionally wondering at how frequently fills were needed.  However, the narrower ink chamber of that style of filler meant that the relatively shallow fill was still enough to cover the inner end of the breather tube, and also gave slightly greater thrust when the air in the reservoir expanded.  If the collector was partially full, as it might be in a freshly-fed pen, that’s enough to overwhelm it, and there’s your cap-full of ink.

What remedy, then?  Ideally, an Aerometric feed and a fresh tube.  But I don’t have a spare feed.  What I do have is about a meter of the very same Teflon tubing Figment used to make the problematically correct Vac-length tube, which fits very nicely in the back of the Vac feed, and so I cut an Aerometric-appropriate length from that.  I also have a pin and the capacity to warm it, allowing me to put a teeny little hole in the tube, close to the open end of the sac.  Theoretically, then, problem solved.

But I’m in the business of practical solutions.  So, we need a field test.  The first aspect of the test was see if the pen filled at all; the Vac tube is of a wider bore than the Aerometric, and there was some chance this would afflict filling.  Trial proved this fear unfounded, and so we move onto phase two of the field trials.  That is me sticking the pen in my shirt pocket, staggering around for a few hours and exposing it to my raging personal furnace (I have a surface temperature approaching 30C!), and then taking the cap off.


Over a disposable sheet of paper.


Alas, I lack an aircraft to test against serious changes of external pressure.  My parents live on the fifteenth floor of their building, but I don’t expect the 0.07 psi change will really prove much one way or another, so any visit to them will be purely for the pleasure of their company.

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