Holding The Squeeze Bar Down When Pulling A 51 From The Ink

[FarmBoy]

The Special tube is just a tube. It lacks the little breather hole that makes this all work.

 

Will be back later.

[pajaro]

I just did a test on a P51 Special with water, so it would not be messy.

I did the 5 or 6 presses, until no more air was being pushed out the front of the hood.

On the last press, I held it down, and lifted the pen out of the water.

Then I pressed the lever, to see what comes out....very little. hmmmm

 

Maybe my 51 Special has a bad breather tube.

 

Ah Hanh. Told ya so. Breather tube is probably OK.

 

So, how much does that collector hold. Seems like there's a lot of faith in collector magical ability to hold ink.

 

So, what did Parker put a sac in the aero for at all? Just to pull ink into the collector and then issue instructions to empty the sac again? The collector is the totality of the ink reservoir? Oh, I forgot the breather tube. There might be a milliliter there too.

Edited July 14, 2014 by pajaro

[Komitadjie]

 

Originally the collectors were made on a lathe and then the fins created using a compound saw. Later on they were injection molded. What is amazing is that the early collectors were made to incredibly fine tolerances of about 1/1000 of an inch.

 

Wow, that's a LOT of machine work, particularly in the era before CNC equipment! I work as a design engineer at a place that is very heavily into CNC machining at the .001 level and sometimes (as infrequently as we can manage, it's a pain) less. We have some very, very modern CNC equipment, including a couple very nice Swiss screw machines, and that collector impressed the heck out of me. Cutting those without binding, melting or damaging the fins as you did was no mean trick!

[Jerome Tarshis]

I leave the full and authorized explanations to FarmBoy or others. The time when I thought I understood the breather-tube story is long past. But I would like to introduce an important idea or two. The breather tube of the 51 Special (and, I assume, the Super 21 and perhaps the British Aero Duofolds) is substantially shorter than that of the 51. This is important because when the non-51 pen is full of ink and is held nib up in the owner's pocket on an airplane, the breather tube doesn't have any ink in it: the tube is too short to touch the ink. That means the air in the sac (and the breather tube) can expand upward without expelling ink from the pen. Ergo, no need for the little hole that characterizes the Aero-metric 51.

 

The 51, by contrast, has a breather tube long enough to dip into the ink when the pen is in a pocket nib-up. When air expands in the tube, the idea is that it passes off harmlessly by way of the little hole and the pressure is not such as to expel ink. (Here I feel foggy, whether or not I'm telling the right story.) The shorter breather tube is why those other not-quite-51 Aeros have a smaller ink capacity than the 51 with the little hole near the nib end of the breather tube.

 

Which brings me to the other fundamental point here. When one is filling the pen by successive squeezes, and there's a breather tube involved in ink capacity, each squeeze is supposed to expel air, not ink. Whereupon that air is replaced by ink. The user squeezes again, expelling more air. When ink has piled up to the height of the breather tube, the pen won't take any more ink, because further squeezes will expel some ink. In principle the ink below the top of the breather tube during filling will not be expelled when the user squeezes the pen. Until the pen has reached full capacity.

 

It seems that in practical use at least some of us are expelling ink when we're not supposed to. Here is where my mind fails and I'd like to hear from a mature adult. I would add, referring to such an adult, that on vintagepens.com David Nishimura says that the Aerometric system reduces the probability of leakage. He doesn't say it eliminates leakage. Which is to concede that between the ideal and the reality there is a gap, in some cases much larger than that little hole.

[Matlock]

Which brings me to the other fundamental point here. When one is filling the pen by successive squeezes, and there's a breather tube involved in ink capacity, each squeeze is supposed to expel air, not ink. Whereupon that air is replaced by ink. The user squeezes again, expelling more air. When ink has piled up to the height of the breather tube, the pen won't take any more ink, because further squeezes will expel some ink. In principle the ink below the top of the breather tube during filling will not be expelled when the user squeezes the pen. Until the pen has reached full capacity.

 

 

Very much in line with how the Parker Vacumatic works. If you get a chance to observe the working of a Vacumatic Demonstrator it all becomes clear.

[OcalaFlGuy]

First, as I'm not an expert myself, this really means squatola.

 

But, Jerome's explanation is not only My understanding of how things work but IMO one of the better written out explanations thereof.

 

Thanks Jerome, that was helpful to Me at the very least.

 

It Does appear that expelling ink from a Non-Special Aerometric 51 when it shouldn't would Most Likely point to a clogged or compromised breather tube.

 

Bruce in Ocala, Fl

[Komitadjie]

That could, I suppose, also explain why I do NOT expel as large of a quantity of ink as I am under the impression that the 51 holds... It's not expelling, because it's staying in the sac where it belongs!

[pajaro]

Refilling an older 51 that presumably has a longer breather tube, where the sac is still clear because of little use, I pressed six times, holding the bar depressed the sixth time as I pulled the 51 out of the old Skrip bottle (new ink). Very little ink appears in the sac. I can see the breather tube. Of course, the only way to test this is to disassemble a 51 and refurb it with a new breather tube and sac to quell all objections of how everything in my pen is old and must be in need of replacement.

 

It's easier to either fill it the way it works or just use a working Sonnet/Waterman/Montblanc/Pelikan/Conway Stewart/Sheaffer.

[richardandtracy]

OK, just try squeezing the bar down a little on the last squeeze before withdrawing from the ink. You are just trying to suck 0.1cc or so of ink up into the sac, not the full 1.5cc, so won't want a full squeeze. It does work for me, but then, I do know that my breather tube is intact having replaced it a couple of years ago due to FarmBoy's kindness. If the breather tube is broken or the aero hole is corroded much bigger than it should be, you will squirt lots of ink out on that last squeeze, which will not be good, and must adjust the squeeze to suit.

 

Regards,

 

Richard.

[Florida Blue]

David Nishimura says that the Aerometric system reduces the probability of leakage. He doesn't say it eliminates leakage. Which is to concede that between the ideal and the reality there is a gap, in some cases much larger than that little hole.

 

In a paper booklet that I have in a 51 set Parker gives very specific instructions on how to bring an Aerometric 51 on an airplane to prevent leaking:

 

"When you fly...

 

Before boarding plane, expel 6 or 8 drops of ink from your "51" pen by gently squeezing filler bar. Carry pen point-up until cruising altitude is reached."

 

Parker must have thought that the hole was not always sufficient enough to prevent leaking. I'm assuming these instructions are for a pen that has just been filled. This booklet is from a late 1950s set.

 

I thought your explanation was very good by the way.

Edited July 14, 2014 by Florida Blue

[Ron Z]

A lot of misunderstanding of how the 51 (or Vacumatic) filling system works. Take a look at this blog post for a discussion of why you can't judge how full a Vac or 51 is by the amount of ink that you get back out of the pen after filling.

The slit(s) of the feed are much smaller than the ID of the breather tube. Both air and ink follow the path of least resistance, which means that it goes through the breather tube, with relatively little or none passing through the feed during the filling process. The pen fills in increments with each stroke of the pump or squeeze of the pressure bar, flowing over the edge of the breather tube into the barrel, Aereometric or Vacumtatic as it's filled. The pen will fill only as high as the top of the breather tube, and no farther. So if you press the pressure bar or pump down, and then release it after filling the pen, you aren't losing much if any ink. But you are avoiding a flooding pen. The reason is that if the breather tube and collector aren't cleared of excess ink, the ink will expand and can flood as your hand (or body if in a pocket) warms the pen.

 

Do take a look at the blog post. There are pictures and more detail that may help.

[Komitadjie]

Ah, that was a very clarifying blog post, Ron, thanks. And it does explain darn well why I can write forever with the thing, but it only gives out a couple drops if I squeeze the bar.

 

Those Parker engineers were rather sharp.

[OcalaFlGuy]

Yep, IMO, El Zorno nicely frosted the cake of Jerome's explanation.

 

<Fist bump to the both of them!>

 

Bruce in Ocala, Fl

[pajaro]

Here's something I don't get. I put my 51 in the ink, squeeze 4 times, no more bubbles come out, and I'm still holding the bar down. Pull the pen out of the ink, release the squeeze bar. Put the pen back in the ink. Squeeze 4 times, holding down the fourth time. Lots of bubbles came out on squeezes one to three. Hold the bar down on squeeze 4, pull the pen out of the ink, elease the bar.

 

What I don't get is, after squeezing four times and holding the bar squeezed as I pull the pen out, when I put the pen back in the ink and squeeze 4 times again, bubbles come out on squeezes one to three. This doesn't appear to validate the explanations. I am getting a headache.

[Charles Rice]

I don't get it either. Me, my pen fills just fine letting go the bar while it's in the ink. A case of whatever works!

[pajaro]

I don't get it either. Me, my pen fills just fine letting go the bar while it's in the ink. A case of whatever works!

 

I agree. My pen has been doing it for forty-four years.

[jinzo1988]

This may have nothing to do with the filling issue at hand, but before posting I re-read this thread to make sure I was not duplicating info. On Aerometric 51's, the tiny hole at the end of the lucite barrel (or on some of the later 51's, on the side) needs to be kept clear of debri as otherwise it can (read may or may not) prevent the ink sac from properly adjusting to temps and air pressure. That can lead to flooding or drips that mimick a pinhole in the sac. I read this somewhere so can't take credit - but it fixed two found-in-the-wild Aero "drippers" for me. Finger oils, crud and pocket fuzz over time can build up and close those holes.

[Charles Rice]

 

I agree. My pen has been doing it for forty-four years.

Come to think of it, I've had mine for 44 years, too.

[pajaro]

This may have nothing to do with the filling issue at hand, but before posting I re-read this thread to make sure I was not duplicating info. On Aerometric 51's, the tiny hole at the end of the lucite barrel (or on some of the later 51's, on the side) needs to be kept clear of debri as otherwise it can (read may or may not) prevent the ink sac from properly adjusting to temps and air pressure. That can lead to flooding or drips that mimick a pinhole in the sac. I read this somewhere so can't take credit - but it fixed two found-in-the-wild Aero "drippers" for me. Finger oils, crud and pocket fuzz over time can build up and close those holes.

 

If you have a later 51, and my favorite one is a mid to late 1960s production, the vent hole is on the side.

[Charles Rice]

 

If you have a later 51, and my favorite one is a mid to late 1960s production, the vent hole is on the side.

Mine is on the side, too. Never gave it any thought at all.