Parker 61 Fountain Pen: Understand Its Capillary Action

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Discussion Overview

The discussion centers around the capillary action mechanism of the Parker 61 fountain pen, particularly how its orientation affects ink flow. Participants explore the implications of gravity and capillary action in both upright and upside-down positions of the pen, considering the unique design of the pen and its historical context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that the pen fills with ink through capillary action when dipped, but express uncertainty about the internal mechanism and whether it involves a sponge.
  • There is a debate about the effects of gravity on ink flow when the pen is oriented upside down, with some arguing that gravity should pull ink towards the nib, while others contend that it actually pulls ink away from the nib.
  • Participants discuss the ambiguity in terminology regarding the orientation of the pen, with differing interpretations of what "upside down" means in the context of fountain pens.
  • Some participants propose that the shape of the meniscus may change when the pen is upside down, potentially stopping capillary action entirely.
  • There is mention of how different pen designs (e.g., retractable nibs) may influence the orientation and ink flow, highlighting variability in fountain pen mechanics.
  • One participant notes that capillary action is not solely dependent on gravity but is influenced by it, suggesting that an upside-down pen may have different ink saturation levels compared to an upright pen.

Areas of Agreement / Disagreement

Participants express differing views on the effects of pen orientation on ink flow, with no consensus reached on the mechanics of capillary action in this specific context. The discussion remains unresolved regarding the implications of gravity and the design of the pen.

Contextual Notes

Participants acknowledge limitations in their understanding of the pen's internal structure and the specific conditions under which capillary action operates. The discussion reflects a variety of interpretations and assumptions about the mechanics involved.

physicsisphirst
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this is a unique fountain pen from the 60s in that you don't squeeze anything to get ink into it. you just dip the solid one piece 'cartridge' into the ink and it fills, presumably through capillary action - i don't know what's inside, but i doubt if it is a sponge to have lasted all these years.

now if i keep the pen rightside up (the way you'd carry it on the clip in your pocket), i can write with it immediately. if i keep it upside down, no ink makes it to the nib despite the seeming gravitational advantage.

if the instrument works on capillary action, the meniscus needs to be concave up in order for the surface tension to cause the ink to flow upwards against gravity. if we turn the pen downwards, the same capillary action will presumably cause the ink to go in the other direction despite gravity.

the only difficulty I'm having with the above reasoning is that when upsidedown

1. the ink doesn't flow out of the other end or flow to the nib
2. the full-weight of the ink is towards the nib, but doesn't make any progress to it

what I'm wondering is whether when upsidedown, the shape of the meniscus is sufficiently altered at both ends (though i don't know if it is correct to call it a meniscus at the bottom) so that capillary action stops completely.

if so, this would seem to suggest an asymmetry in the capillary tubes perhaps (may be they narrow with proximity to the nib?), so that ink goes only one way?

ideas or explanations?

in friendship,
prad
 
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physicsisphirst said:
now if i keep the pen rightside up (the way you'd carry it on the clip in your pocket), i can write with it immediately. if i keep it upside down, no ink makes it to the nib despite the seeming gravitational advantage.

Why would there be any "gravitational advantage" to the flow of ink in an upside down pen?
 
pallidin said:
Why would there be any "gravitational advantage" to the flow of ink in an upside down pen?

i meant just towards the nib, pallidin.
presumably with an upside down pen, gravity would pull the ink towards the nib which it does for regular fountain pens and ball points (which don't write too well when the nib is pointing up).

in friendship,
prad
 
physicsisphirst said:
i meant just towards the nib, pallidin.
presumably with an upside down pen, gravity would pull the ink towards the nib which it does for regular fountain pens and ball points (which don't write too well when the nib is pointing up).

in friendship,
prad

Doesn't "upside-down" mean the nib would be the uppermost part of the pen? Then gravity would pull ink downward, away from the nib.

What am I missing?
 
Redbelly98 said:
Doesn't "upside-down" mean the nib would be the uppermost part of the pen? Then gravity would pull ink downward, away from the nib.

What am I missing?

we just have a discrepancy regarding interpretation of orientation. let me rephrase it.

if the nib is pointing down, i would think gravity would pull the ink towards the nib - which it doesn't seem to be succeeding in doing if we just leave the pen lying around with the nib pointing down.

if the nib is pointing up, gravity would pull the ink away from the nib, but it seems the capillary action overcomes this drawback and the ink makes it into the nib anyway.

in friendship,
prad
 
physicsisphirst said:
we just have a discrepancy regarding interpretation of orientation.

Not to beat a dead horse, but I think it's important for those posting questions to phrase their questions in a way that is commonly accepted.
For example, the "normal" orientation of a pen is either horozontal(such as on a table), or vertical(such as in a pen-holder) whereas in that last case the nib points downward.

Therefore, a normal vertical orientation of pen is that the nib points downward.
Thus, an "upside-down" pen infers(to the general public) that the nib is at the top.

You presented the exact opposite.

This is why we were confused.
 
I must say this, however, in your defense:
There are some pens which has a removable cap around the nib. The cap sometimes has a clip, which puts the nib in an inverted position when clipped on a pocket!
Yet, other pens have a clip mechanism on the opposite end to keep the nib pointing down

So, I understand your position. But my(and others) previous post still firmly stands.
 
pallidin,

i agree with you and apologize for causing this confusion.

i wrote
"i keep the pen rightside up (the way you'd carry it on the clip in your pocket)"
and it wasn't sufficiently clear especially since pens do have clips in various places though i have never seen a fountain pen that is carried nib downwards in a pocket - i wonder what the consequences of doing so might be for pens other than the parker 61, but I'm not going to try it.

so if the orientation issue is clear now:

1. when the nib points up, the ink flows to the nib.
2. when the nib points down (for extended periods of time) the nib seems to dry up.

are there any ideas as to why this might be happening?

in friendship,
prad
 
physicsisphirst said:
1. when the nib points up, the ink flows to the nib.
2. when the nib points down (for extended periods of time) the nib seems to dry up.

No need to apologize. We are all here for learning and sharing!

For 1 and 2 why could it not be said:
1: when the nib points up(for extended periods of time) the nib seems to dry up.
2: when the nib points down, the ink flows to the nib.
 
  • #10
well palladin, it's not that it couldn't be said, it's that it doesn't happen at least for this pen which i think works on capillary action. the exact opposite happens as i outlined.

i think it could be the way you state it though for a squeeze or cartridge fountain pen and definitely for a ballpoint (though that's really a different story).

in friendship,
prad
 
  • #11
physicsisphirst said:
...though i have never seen a fountain pen that is carried nib downwards in a pocket

Sure you have. Like those pens which you have to twist in order to extend the nib.
The clip(in this case) is always on the opposite end of the pen from the retractable nib, thus keeping the nib downwards while clipped.
 
  • #12
Hmmm. Maybe I am unfamiliar with your specific type of pen.
If so, my mistake!
 
  • #13
The original reason as to why pens were inverted(with the nib up) had nothing to do with promoting ink flow for writing, rather, had everything to do with helping to prevent ink-leakage onto a garment.
 
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  • #14
In fact, ink flow is never promoted in an inverse capillary situation. It is reduced.
 
  • #15
I think I know what the root problem is now.
Capillary action is not specifically dependent on gravity, but it is affected by it.

Take two capillary-drawn ink pens. One with the nib pointed-up and the other pointed down.

Over brief time, the one pointed-down will have an ink saturation in the nib far in excess of the one pointed-up, due solely to gravitational effects.