An alternative look at ink wetness

[RJS]

  On 1/27/2022 at 9:54 PM, LizEF said:

The water resistance is probably a side-effect of everything else (or a natural attribute of the dye + other ingredients) so that they can't replicate it without also changing the color (of the other ink).

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I've seen it claimed on here that that ink is cellulose reactive? Which is quite unusual, right? I don't know how they achieved that or if it is linked to the specific colour. 

[LizEF]

  On 1/27/2022 at 11:01 PM, RJS said:

I've seen it claimed on here that that ink is cellulose reactive? Which is quite unusual, right? I don't know how they achieved that or if it is linked to the specific colour. 

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Yeah, no idea.

[dipper]

Here are some attempts to answer a few of the interesting questions raised recently. . .

 

Ink and air "share a channel" in the same way that rainwater and motor vehicles share Trumpington Street in Cambridge UK. (Google maps street view.) Vehicles move in the large space of the road surface. Rainwater moves in the deep gullies at each side of the road. Each stays in its separate space, whilst both "share" the same route between the outskirts and into the town centre, and may be travelling along that route in opposite directions.

 

Why does the ink stay separate from the air, when the channels are one on top of the other? The reason is physics, but magic at the same time. Compare Trumpington Street first: Gravity makes the water flow off the road and down into the gutters, common-sense makes vehicle drivers stay up on the road. Alcohol-affected students late at night can also enter the gutters.

In a pen feed, capillary action draws ink into the narrow feed slot only, whilst atmospheric pressure pushes air into the larger cross-section breather space. Many disturbing factors, including again alcohol probably, can disrupt that tidy arrangement.

 

Air bubbles mixed into the ink inside the capillary feed slot? That is not something I have studied. Transparent feed under a microscope.... oh yes please! ... I am keen to know if any bubbles can be seen. Photos would be great, but not essential.

 

Flows not so strictly divided? Well they can be so, at least some of the time. Peering through my microscope (that is old enough to make LizEF's seem positively space-age), looking down through a nib breather hole into the capillary slot below, I can see bright light reflections glinting off the concave ink meniscus down in the slot, whilst there is still an open air space in the upper wider part of the same slot that the nib body bridges over.

 

Can ink and air have separate channels? They do already have separate channels in some portions of the feed, depending on specific manufacturer designs. But perhaps the question was, can they be separate over their entire lengths? It is certainly possible to design a fountain pen with separated paths:

Theoretically, the pen above should work OK. In reality though it may suffer from serious unforseen problems. When laid on its side...  will all the ink leak out through the pipe "d", and air enter through capillary pipe "j"? (And that may be a clue to a benefit of the typical overlaid breather and ink channels at the back end of pen feeds. That design may be "self sealing", as any small volume of ink flooded into the breather space may have the effect of filling the whole channel and thus preventing any air from entering the ink chamber?)

Perhaps some vintage or unusual pens exist with entirely separate feed and breather paths? An old Rotring technical pen comes close to that, with the breather being a helical gap that is concentric with, and between, the central ink feed and the pen grip section.

 

Only one capillary path? That statement was oversimplified! Capillary slots are frequently double slots or more. Thanks for the correction.

So what is it that there is "only one of"? There is only one system of narrow capillary channels. That system may branch, separate into multiple parallel tracks, rejoin again at the nib tip (or not), but, whatever its form, it is doing just one thing. It is carrying ink away from the ink chamber and down onto the paper.

In contrast, air movements, into the pen, are not "capillary". Those air movements can be controlled by ink surface tension (at "h" in the crazy pen sketch above). The term "capillary action" describes one aspect of surface tension effects - the general attraction of liquids into narrow spaces.

Also, for completeness, and with thanks to Amadaeus W. for this, the "side fins" and some related parts of a pen feed, occupy a middle-ground. The gaps between the fins are almost narrow enough to be considered as "capillaries". They have just enough capillary action to be able to hang onto accidental ink burps etc, so the pen does not leak ink in normal use conditions.

But the fin gaps do not hold on to the burped ink permanently. The main capillary system easily draws that ink away from the fin gaps, instead of from the ink chamber, when the pen is writing.

 

Difficulties flushing feeds. Ink hangs on somewhere inside? That is not unexpected. Water can be vigorously flushed through, taking the easy route through the larger breather channel(s), with ink staying comfortably snug, down in the depths of a narrow capillary slot as the water torrent rages past overhead!

That is why I "flush" my pens in the normal manner, but then also fill the pen with water (plus a drop of surfactant), and stand the pen upright, nib down, on a stack of folded paper towel. The pen will empty into the towel in a few minutes, or up to a hour for some pens. It takes that long because the pen is operating in its normal mode, the same as when writing. The water is flowing inside the capillary slots, and carrying away ink - out into the paper towel.

 

A borescope in fractions of a millimeter? .... Would a 0.1mm slit scraper/gauge help? Thin flexible safety razor blade - the old fashioned type with two sharp edges. (Digital callipers show thickness is 0.10mm.) Rub off sharp edges with fine wet&dry paper. Snap blade into two long pieces with pliers. Rub off any bent corners at the snapped edge to make a square edge. Polish the edge with micromesh so it is still square but has no sharp corners.

Result is a perfect fit in (some) feed slits, telling us the feed slit width is close to 0.10mm AND giving a way of scraping out a build-up of pigment-ink particles without damaging the capillary slit.

 

Somebody somewhere was a genius. That would be Mr Waterman, and a few of his contemporaries. (Or perhaps one or two contemporaries were the real geniuses, who deserve most of the credit. It is a fascinating area of historical research.)

https://danielkirchheimer.com/articles/blotting-out-the-truth/

 

 

 

[LizEF]

  On 1/28/2022 at 4:10 AM, dipper said:

Here are some attempts to answer a few of the interesting questions raised recently. . .

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  (I don't have time tonight to answer properly - must go to bed - but the easy answers...)

 

  On 1/28/2022 at 4:10 AM, dipper said:

Transparent feed under a microscope.... oh yes please!

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If I can stop long enough, I'll give it a whirl!

 

  On 1/28/2022 at 4:10 AM, dipper said:

A borescope in fractions of a millimeter? .... Would a 0.1mm slit scraper/gauge help?

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I was thinking more along the lines of drunken nanites driving into the ditch and while streaming video to us...

[InesF]

  On 1/27/2022 at 6:07 PM, LizEF said:

That's actually not so hard - a relatively simple chemical test.  When I worked (in IT) at a lab, one of the chemists had memorized the look of the graph-like report of chemicals that make up Coca-Cola, because people sent it in so often to have it analyzed, as if it were something of their own make (presumably so they could do exactly what you describe).  I think it was the TOC machine that put out this report, but it was a long time ago and I could be wrong.  Anyway, they'd run the test, not knowing what the sample was, and as soon as he saw the report, he'd say, "Someone sent us Coke again."

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Ha ha! 😄.

We made our Pizzas in the gas chromatograph oven and people entering the lab had to guess the Pizza type ... 😇

[InesF]

  On 1/28/2022 at 4:10 AM, dipper said:

 

Ink and air "share a channel" in the same way that rainwater and motor vehicles share Trumpington Street in Cambridge UK. (Google maps street view.) Vehicles move in the large space of the road surface. Rainwater moves in the deep gullies at each side of the road. Each stays in its separate space, whilst both "share" the same route between the outskirts and into the town centre, and may be travelling along that route in opposite directions.

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@dipper, I like your comparison - it makes things so much more clear!

I also like your drawing a lot. However, the air channel of the Waterman Carene may be a bit more complex inside.

 

 

Here are some photos I promised:

At first an overview of the 4 nib + feed units. They are from left to right: Waterman Carene (assembled), Santini ebonite dismantled, Pelikan M600 assembled and Aurora Optima assembled.

 

The Carene was the hardest to photogrpah and this photo is not good (I know). The centre circle is the inlet to the feed, a bit blurry but the three ink slits can be (seen) guessed. The big circular segment is the air inlet, the smaller slits are the ink outlet.

 

The Santini feed has a combined 1-slit-double function channel. The circular part is the air inlet (starting at the breather hole) and the thin deep slit is the ink outlet.

 

The Pelikan M600 has three slits. I guess the one slit in the middle may be the air inlet. However, the big round hole in the centre is a dead end hole!

 

The Aurora feed has one combined channel with the bigger square slit for the air inlet and the small below as the ink outlet. There is also this groove between the blue inner part and the black channel wall. I cannot figure out if this is functional or only decorative.

 

This is to your enjoyment and to our all awe about those pioneers who first had figured out how to construct a fountain pen feed. 

[InesF]

Coming back to ink comparisons.

I had bought one more ink, the Aurora Blue-Black in the standard version. To avoid the extra shipping cost, I ordered an Aurora Blue Mamba with the ink - and broke the "no new pens in 2022" resolution. 🤭

 

To my surprise, this Aurora ink has, almost equal to Diamine Green-Black, a very high viscosity out of the bottle. With this one addition, and the Graf v. Faber-Castell Turquoise which I assume was somehow wrong deleted, here the "final" ink properties table:

 

[LizEF]

  On 1/30/2022 at 3:17 PM, InesF said:

Ha ha! 😄.

We made our Pizzas in the gas chromatogarph oven and people entering the lab had to guess the Pizza type ... 😇

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Not sure I'd want to eat something that had been though any instrument in the lab...  (Of course, in our lab, no food or drink were allowed, at all - not even gum or water - there were drinking fountains, or you could go downstairs (out of the lab) to the cafeteria, but that was it.)

[InesF]

  On 1/30/2022 at 3:49 PM, LizEF said:

Of course, in our lab, no food or drink were allowed

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... that was not a question of allowance! 

[LizEF]

  On 1/30/2022 at 3:52 PM, InesF said:

... that was not a question of allowance! 

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Bad Ines!

[txomsy]

Long ago, in pre- security-conscious times, much was allowed (almost anything) in the lab. You were supposed to be doing Science, to know what you were doing (within the little that was known) and that what you did was justified in the spirit of Science --even if only to keep your spirits high (or way cold below zero) to overcome the frustration often associated with scientific lab work.

 

We had a coffee machine at the wet lab which made for lots of hours of socialization, interesting discussions and -as a side benefit- helped keep us awake in long experiment nights. That's unthinkable now, although some long-lasting IT-only labs still keep one as a reminiscence.

 

I remember many experiments that would have been absolutely impossible nowadays. Heck! We just had a discussion last September on how to solve a problem that would have been trivial way back then and a) the technology was unthinkable today (and had been for decades) and b) because of that, only the oldest of us remembered it did once exist (but most of us had to confess, had totally forgotten how did we do it --yet we might lookup old books --if it were allowed to do it and the materials available.

 

This -and some comments on nibs and fees- has led me to wonder how did makers "see" the problem in the old times. Was it only trial and error? I suspect they'd have some theories and engineers would base their designs on them. Wouldn't it be easier to just check old patents and see the explanations and justifications they gave?

 

 

[Karmachanic]

 

  On 1/30/2022 at 3:45 PM, InesF said:

To avoid the extra shipping cost, I ordered an Aurora Blue Mamba

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Puchasing a €600 pen to avoid a €6 shipping fee.  Works for me!  Perfect fountain pen afficionado logic.  😁  

[dipper]

  On 1/30/2022 at 3:30 PM, InesF said:

this photo is not good (I know)

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Those four photos of the rear-ends of pen feeds are excellent.

Fascinating to compare them.

Thank-you for posting.

 

That is an important part in the functioning of a fountain pen. It is hidden from view, never glamorous, sometimes badly made and sometimes high precision (well done Pelikan), always overlooked in comparison with those flashy show-off "nib" things, and horribly difficult to photograph.

 

I am now inspired to try photographing some of my feeds. Will post soon if successful.

[InesF]

  On 1/30/2022 at 6:18 PM, txomsy said:

This -and some comments on nibs and fees- has led me to wonder how did makers "see" the problem in the old times. Was it only trial and error? I suspect they'd have some theories and engineers would base their designs on them. Wouldn't it be easier to just check old patents and see the explanations and justifications they gave?

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Indeed, @txomsy, digging through patents may help. I grew a bit lazy in my old days and read not more than a handful of the patents I found so far. Most of them are before 1930 and didn't tell much about the details. I was a bit bored and abandoned hope to discover the secrets hidden there. However, the evil in me believes that current design and adjustments may not be published accordingly. I guess it is more towards manufacturers secret (with the follow-up estimation: who would buy feeds and cross-cut them in several directions to discover their function?), the business sector is not big enough to have industry espionage.

 

PS: Awareness about lab safety and employee protection has changed a lot - mostly to the better, not always towards easier life.

[InesF]

  On 1/30/2022 at 3:58 PM, LizEF said:

Bad Ines!

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"Two souls dwell, ah, in my breast!"

[InesF]

  On 1/30/2022 at 8:09 PM, Karmachanic said:

Perfect fountain pen afficionado logic.  😁  

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@Karmachanic, you got me! 😊

I'll start therapy next month .... 

[LizEF]

  On 1/31/2022 at 6:35 AM, InesF said:

"Two souls dwell, ah, in my breast!"

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True for us all, my friend.

[dipper]

More ink feed photos.

 

Fortunate that this particular pen got chosen for a photo session. It is an old favourite that I rarely use now. The last photo may show why it has been retired. Something was revealed that needs fixing.

 

A cheap old no-name pen, that did write beautifully - years ago.

Broken clip, and cracked cap repaired with tape, are results of long useage.

 

Cheap nib, not tipped, just tip sides folded down - makes it an Architect tip!

 

Big air breather intake under the feed.

 

Ink capillary slot on top, joins with air breather half-way up the feed length.

 

Combined air plus ink channel steps down near the back end of the feed.

 

And a rather typical air-out / ink-in opening at the rear tip.

But the narrow opening of the ink capillary slit looks squashed, and is almost closed off!

 

I think I know what has caused this. Pen is currently fitted with a Schmidt converter. In the past though a few dozen ink cartridges went through the pen; The type with a little hard plastic ball sealing the cartridge opening. They need some force to be inserted into the pen and "pop" the ball free. The plastic balls have deformed the feed, causing the ink slot to become nearly closed shut.

No wonder this pen used to be so much more wet than it is now!

[InesF]

  On 2/1/2022 at 3:59 AM, dipper said:

But the narrow opening of the ink capillary slit looks squashed, and is almost closed off!

 

I think I know what has caused this. Pen is currently fitted with a Schmidt converter. In the past though a few dozen ink cartridges went through the pen; The type with a little hard plastic ball sealing the cartridge opening. They need some force to be inserted into the pen and "pop" the ball free. The plastic balls have deformed the feed, causing the ink slot to become nearly closed shut.

No wonder this pen used to be so much more wet than it is now!

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Hi @dipper, those photos are highly interesting.

The air channel along the feeds length can be comparably wide, as long as the most narrow part (at the feeds nipple) is accordingly narrow.

It's so fascinating to see the ink channel at the cartridge end (at the nipple) deformed and compressed at a still working fountain pen. I guess, when the ink slit will be blocked totally, the pen will still work, but may have a much more dry performance. In such a case, ink and air have to share the same opening with the ink forming a thin film at the corners of the square and the air in the middle.

I can't estimate if such a pen will start to be flow limited - but I guess (again) it will not - although, it can be close to the limit. However, you will recognise if a fountain pen is flow limited - and if it is, you will hate it!

 

You may cure this feed by carefully re-open the ink slit (with a razor blade or a sharp knife). Don't worry, if you make a bigger cut as long as it is not too deep into the feed - the pen will work like new.

 

Good luck and thanks again for sharing this!

 

PS: the good old no-name pen looks like it could tell interesting stories about which inks it had been filled, how it earned its band-aid cap band and how many kilometre of ink line it has drawn so far. May it draw many more kilometres! 😎

[dipper]

  On 2/1/2022 at 12:28 PM, InesF said:

I guess, when the ink slit will be blocked totally, the pen will still work, but may have a much more dry performance

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True. And that is why my old favourite has spent years stored in the pen-retirement-home.

 

Until today!

Ink capillary reopened...

 

And pen refilled to test. (Used a converter and bottle ink, not ball-sealed cartridges, to avoid repeating the damage.)