What Causes Railroading Even At Slow Writing Speeds?

[beanbag]

Hello folks,

 

There is something I am trying to figure out about how ink manages to stay between the tines of a vintage flex pen. I have a fairly flexy Wahl #2 ringtop pen, and under some conditions, it can spread the tines pretty wide (2mm), yet still have a relatively dry ink flow, and some other times, the flow is more wet, but I can't spread the tines apart by much before the web between them pops. This is even if I move the pen at really slow speeds, so therefore I don't think it is a flow issue.

 

Is this only a property of the ink, or are there other factors involved?

 

For example, sometimes I can't spread the tines by more than about 1.3mm before the web pops. There is a youtube video where somebody is able to flex out to about 3mm, yet still have a relatively dry flow (i.e. not dumping pools of ink). How is it that that guy's ink is able to stay between the tines?

[bardiir]

The interesting fact here is the completeness of the ink bubble. If it breaks away from any of the points it will burst.

 

Ink flow: The ink on the nib runs too thin or the ink flow ends

Time: After a while it will burst, think soap bubbles

Paper: Paper soaks up too much ink or is too rough

Nib: If the nib is hydrophobic between the tines it can cause the ink bubble to destabilize

Feed: If there is too much space between nib and feed then the ink underneath the nib can run back into the feed instead of into the nib causing ink starvation again

 

And probably a few more...

[Goudy]

For example, sometimes I can't spread the tines by more than about 1.3mm before the web pops. There is a youtube video where somebody is able to flex out to about 3mm

 

In that case, maybe 1.3mm is as far as you should flex it. Your nib and feed may simply be designed to work best within that limit. Every vintage nib is different and very few can comfortably spread to 3mm without problems (including permanent damage to the nib).

 

Since you've posted a few times about flex nib issues, you may be interested in this blog post by David Nishimura

[ac12]

Do NOT push your nib.

If the pen and ink won't do beyond 1.3mm (however you measure that degree of precision), don't do it.

Unless you really know what you are doing, go very easy on the flex. Once you spring the nib, that is is, the nib is ruined/destroyed.

Personally, I would not go beyond 1mm, and probably not even that, unless I was using a dip pen with a $2 Nikko G nib. Then if I sprung the nib, it is only $2 to replace the dip pen nib, not $75+ for a vintage flex nib.

[Mauricio]

Railroading can be caused by multiple reasons. Among the most common reasons are: (#1) An improperly setup nib and feed onto the fountain pen body. (#2) Improper use of the flex nib, whether the nib is being pushed way too hard, rotated at an angle in relation to the writing direction, etc.

[beanbag]

The interesting fact here is the completeness of the ink bubble. If it breaks away from any of the points it will burst.

 

Ink flow: The ink on the nib runs too thin or the ink flow ends

Time: After a while it will burst, think soap bubbles

Paper: Paper soaks up too much ink or is too rough

Nib: If the nib is hydrophobic between the tines it can cause the ink bubble to destabilize

Feed: If there is too much space between nib and feed then the ink underneath the nib can run back into the feed instead of into the nib causing ink starvation again

 

And probably a few more...

 

The last two reasons you mentioned are interesting. Today after some poking around with nibs and feeds, I got into a situation where the pen, after being flushed, dried, and reloaded with ink, wouldn't start. In one case, even though there was ink in the feed grooves under the nib, the ink wouldn't run down the nib slit. Then after some prodding, I got ink there, but when I press down on the nib to split the tines, I saw the ink run right back up the slit. It did get started eventually and worked more or less normally after that.

 

So perhaps somehow the tip or slit became slightly hydrophobic, or as you said, there is something adjusted wrong with the feed position / gap such that flexing the tines causes the ink to get sucked back up.

 

I took it apart again to wash with soap and water, but at the same time ended up changing the feed adjustment again. So therefore I was not able to isolate the cause, but it sure does seem that these flex nibs and feeds are finicky.

[Christopher Godfrey]

I find your last post more interesting than your very first, beanbag! I wonder if your fingers were very slightly contaminated (oil, some sort of grease?) and hence the hydrophobic phenomenon...?

[bardiir]

I'd think along the lines of oil from the hands too actually. If you got issues starting up a pen with the hydrophobic phenomen try some Rohrer & Klinger Salix, it's a pretty agressive ink and does eat away the oil on the nib. I use it for the first time when starting up my Zebra G nibs (although this might actually get to be an rarer occassion now that the Titanium ones get month of ink up time without a sign of corrosion on them.

 

Btw you don't need to worry about Salix eating away on the pen. It's still pretty tame in comparison to for example some Noodlers inks. It's just my experience that it is very agressive towards oil and will even flow along tines that have a residue of silicon grease

[beanbag]

I "fixed" three issues with this nib yesterday when I looked at it under the microscope. One was that the tops of the tines were tilted a little bit away from each other, meaning that the slit was wider at the top than the bottom. I fixed that by prying up on the shoulders of the nib while pushing down near the breather hole.

 

Another issue was that one of the tines was bent slightly towards the other, such that the nib slit was almost a constant width, and only tapers down in the last few mm. I also fixed that by using a stainless steel shim to bend out the first few mm of the tine. Well, maybe not completely fixed, but better than before.

 

Thirdly, I did a little bit of nib polishing on polyester-backed sandpaper, i.e. the kind that is not padded like micromesh, to remove some "baby's bottom" (if there was any at all - hard to tell).

 

So the starting issue has improved, but I still have that "web of ink is popping" issue that causes railroading.

 

Under the microscope, it looks like the insides of the nib slit has little scratches, although they aren't like user-created gouges, but more like "it was machined, but never polished" kind of scratches. I wonder if the capillary action will be better if the surface were smooth, or instead had these little micro-channels?

 

I did wipe down the nib with isopropanol, but I do have a ultra-sonicator and more powerful detergents in lab that I can try out.

 

So far, the thing that has made the biggest difference was the ink. Even with the Salix ink, I can put a droplet right on top of the nib slit, and it will just sit there for a few seconds. Then it suddenly realizes something and gets sucked inside. The Iroshizuku inks get sucked in right away, and they also allow me to flex more before railroading. But I know that others can do flex writing with all these other inks that I am having trouble with, so I still suspect something with my pen is not right.

[bardiir]

Well you can flex write with any ink, just not in any pen.

 

If you got issues with the ink flow, try to break the surface tension of the ink as an experiment. As you seem to have access to lab equipment it shouldn't be very complicated, normally you'd take a drop of dishsoap, put a toothpick a mm or so into the soap then stir a 1ml sample of ink or so.

 

Not exactly scientific experimentation as there are no specific amounts but the added surfactant will add to ink flow tremendously by lowering surface tension and the added soap also helps in the formation of soapy bubbles between the tines.

 

But maybe you can do something along these lines with more precision, just be careful with measurement, dish soap is very potent. Adding a whole drop of dish soap to 5ml ink will get it out of the pen instantly, no feed in this world will contain that

 

I've got a whole bottle of Noodler's black with around 1/4 drop of dish soap in it that does allow flex writing even at high speeds with the standard TWSBI feed. I use that when I'm using my TWSBI with a brause rose nib attached

[Bo Bo Olson]

A very informative set of posts...especially the 1/32" of flex that was expected as normal of a 'major' flex nib, back in the Day..

[sidthecat]

1.3mm is a pretty wide dimension for a nib. You may be right at the margin of the nib's capacity. Try leaning back a little.

[beanbag]

If you got issues with the ink flow, try to break the surface tension of the ink as an experiment.

 

I did try the soap water test a while ago, and yes it can span the tines, but also dumps out ink, just like in your experience.

 

Today, I bulb flushed out the nib and feed with something called "Micro detergent", and that did improve the flex performance a bit, although it also made the ink flow wetter.

 

1.3mm is a pretty wide dimension for a nib. You may be right at the margin of the nib's capacity. Try leaning back a little.

 

I know my nib can flex out to 2.1mm, although I usually don't do that. But this is just an issue of mechanical damage. What does the 1.3mm have to do with the web popping? At some point, I could do 2.1mm, and other times I can't go past 1.3mm.