I was talking to another collector about big pens and we both nothed that sometimes the pens will write fine and then occaisionally ink builds up along the bottom of the nib in a big drop and then will release on the page.

we have a couple of theories. His is that it has to do with the ink getting warm from the hand.

I switched to Noodlers polar ink, a notoriously thick ink, and it stopped. But with vintage Waterman blue-black, it happens un every fill until I empty about half the ink. I am thinking it might be simple a combination of viscosity and the weight of the ink pressing down on the feed. In short, it is a feed adjustment issue.

Before I send this off thoe binder, does anyone have any recommendations. David, with your collection of big pens, I hope you have insight.

Hi,

Good question, though I note I am not a pen restorer (i focus more on collecting and market pricing, etc). I have had the pleasure to watch some of the best restorers do their work. Many big old pens have early style feeds (spear, spoon) vs later, believed-to-be-more-reliable comb feeds, etc. Beyond that observation, I will need to refer you to the repair guys. Perhaps you should post this in the repair forum.

regards

david

In general, pens that are carrying enormous quantities of ink are going to be more vulnerable to surges in ink flow. Every movement of the pen sends that mass of ink sloshing around. At the same time, a voluminous ink reservoir means that once some of the ink is used up, there is also a voluminous air reservoir -- and thus, more vulnerability to ink expulsion as a result of expansion of that air, whether due to heat or changes in atmospheric pressure.

The problem is, if anything, compounded in large pens that use rubber sacs, since most modern sacs are not really thick and stiff enough to resist deformation under the forces noted above.

I wonder then what the fix is. One could double sac the pen. One could also use a smaller size sac.

but I wonder why a huge danitrio or namiki eyedropper does not have this problem. What is it about the feed that would make a vintage pen more vulnerable?

The devilish thing is that this is a pretty simple mechanism. and yet flow control is just a devil of a problem. I have noticed that a minor variation in the viscosity of the ink can have a profound effect on how a vintage pen writes. I bought vintage ink from teh manufacturers thinking that this would be a panacea; that is not the case. 1929 waterman ink in a 1929 waterman pen is not always a good thing.

Given that moderns don't seem so prone to this, I am wondering whether to mess with the sac or mess with the nib adjustment.

Would ink residue in the grooves in the feed be an issue? is there a rule in terms of how far out the nib extends beyond the feed as it relates to the sudden flow?

By the way, the other collector specialized in viscosity research. He is working on a scientific test of the relation of ink viscosity to this problem. I will share teh results when he is done.

Thanks for the input. People not named David should also fee free to add their opinions

{which reminds me of the song: these are the dave I know, I know I know, these are teh daves I know....}

It's rather difficult to speculate without having the pens in hand, but the issue of hand-warmed barrels is always going to be an issue. Expansion of the air inside the reservoir will lead to flooding, and if the feed isn't capable of catching and holding the overflow, you will get a blob dropping from the nib. If the problem lessens when there is more air in the reservoir, however, I would suspect that warming of the air isn't the culprit, since the effect would be more pronounced with more air. Air-tightness of the reservoir is more likely the issue, given the symptoms. What keeps the ink from simply flowing out the feed is the lower-than-atmospheric pressure inside. With a full load of ink, the negative pressure has to be greater; at the same time, even a small inflow of air would have a much greater effect on the internal pressure than it would if there were significantly more air in the reservoir (air being much more compressible than ink). Pens that drop ink often have leaks so small that the flow problems are their only symptoms.

Hmm, If it is air inflow on a lever fill with a new sac, it would have to be coming from the nib/feed. Perhaps that explains why the seating of the nib is so important. But I can think of some ways to address that particular issue.

Thanks for the insights. I hadn't thought about the pressure differential caused by teh flow of ink out of the sac. That makes sense.