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Rubber-Friendly Ink

rubber sac bulb high-maintenance

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5 replies to this topic

#1 tonybelding


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Posted 15 June 2014 - 01:26

I recently pulled a couple of my Edison bulb-fillers out of storage.  One had traces of ink dried in it, as I must have neglected to flush it before putting it away.  The other looked clean.  Both of them had the rubber bulbs partially melted.
The conventional wisdom says rubber bulbs and sacs (as in lever-fillers, touchdown-fillers, etc.) should last for many years, perhaps decades.  I've been having a lot of failures with them, and I've heard about friends having problems with them too.  I've had restored vintage pens that failed too, much sooner than I would have expected.
My first impulse was to blame today's rubber sacs.  I've heard about bad batches of rubber sacs getting out, and I was left wondering whether today's "good" batches are as good as they were in the Good Old Days.  However...  I also am a fan of Noodler's ink, and I was beginning to wonder if the bulletproof/eternal inks are degrading the rubber and reducing its life span.
I sent the Edison Morgan back to Brian Gray for repair, and he had some interesting comments about the situation.  His observations:
The sac problem is certainly due to a harsher ink, no doubt.  A lot of the modern "boutique" ink makers aren't really considering vintage filling systems, unfortunately.   I have no problems with any ink in our converter pens, but I have had to warn people out some inks with our pens that use latex.  I started getting about one of these issues a month, and now I am getting about 2-4 of these a month.



Inks that he recommends include:  Waterman, Sailor, Aurora and Diamine.  As luck would have it, I currently have no ink from any of those companies!  (I've had Waterman and Diamine in the past, though.  I didn't ask about Herbin, perhaps I should?)


He also pointed out this article from Richard Binder:  http://www.richardspens.com/?care=inks


I found this most pertinent:  "Some other Noodler’s inks, whose identities I have not yet pinned down, will reduce latex sacs to goo."  I haven't pinned them down either, but I've gradually come to believe it.

So...  Where does this leave me?  Do I give up all my favorite "boutique" inks and permanent inks and switch everything out for old-fashioned weak-and-washable colors?  Or do I get rid of all my pens with rubber sacs and bulbs?


OK, let's calm down.  I'm not getting rid of all my vintage pens, that's for sure.  However, I don't write with them all that much on a daily basis anyhow.  I'm using mostly modern pens these days.  So...  I doubt I'll be buying any more modern pens that use rubber sacs or bulbs.  There are plenty of other ways to fill a pen.  Now I just need to pick out a rubber-friendly ink or two for those vintage pens, I guess.  It's an excuse to buy more ink!


Edited by tonybelding, 15 June 2014 - 01:44.

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#2 pen2paper


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Posted 15 June 2014 - 01:54

silicone sacs? a consideration in old celluloid.


natural rubber like plastics are not quite the forever materials that we like to think they are. (until you try to rid the environment, but we're not going There; )

from it's earliest use rubber had manufacturing issues. 


I keep going straight down the middle on this one. I use the inks I prefer, (the 4 above are high on my list), but always clean the pen properly, or I expect early sac failure > since I'm fully aware of latex fail issues. Silicone sac, or less saturated ink is an option too.

> broken record > the environment your pens endure factors too.

emoticon-animal-007.gif~Hi! fountain pen enthusiast here~

#3 tonybelding


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Posted 16 June 2014 - 15:54

I did get around to asking Brian Gray about J Herbin, and he said he isn't aware of any problems with it.


I had to ask because Vert Empire looks so wonderful when I run it through my vintage Waterman Thorobred with the full-flex nib.

#4 bgray


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Posted 16 June 2014 - 16:29

Thanks for posting this.  


The bottom line is that a lot of the harsher inks are indeed an issue for pens that use latex.  It is happening a lot more frequently with our pens in the last 2-3 years, to the point of where it simply cannot be a coincidence.  And this is not a recent phenomena.  Edison seeing a lot more of these issues has to do with the fact that in the last 2-3 years, our volume of sales have increased a lot with pens that have latex sacs or diaphragms.  With the introduction of the Pump Filler and Pneumatic Filler, we sell a heck of a lot more of these pens, so we've seen a lot more melted sacs compared to previous years.


So I have to keep my recommendations at Waterman, Sailor, Aurora, and Diamine for our pens that use latex. 


When it comes to silicone, I found them to not be gas impermeable, which makes them useless.  I used them on the Pneumatic filler when we first launched them, and I had pens mysteriously leaking.  I was completely befuddled, and scratching my head, as these pens were passing all compression and vacuum tests.


I finally ran a trial.  20 pens with latex, and 20 pens with silicone, and I let them sit for 10 days.  80% of the silicone sacs failed, where 0% of the latex failed.  Bottom line, somehow, air was getting into the sac without allowing liquid to leave.  My only conclusion was that they are not gas impermeable on a slow scale, but still plenty fast enough to be a problem.  Whatever the case is, 80% failure rate is not OK.  Heck, 5% failure rate is not OK.


So until there's a better sac out there (silicone or no), we have to use latex, and this means using safer inks.


All Edison Pens with latex come with a letter explaining this in more detail.

Edited by bgray, 16 June 2014 - 17:02.

#5 Ron Z

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Posted 16 June 2014 - 17:20

This is one subject that is sure to fire up a lot of opinions, and defenders of what I call boutique inks.  But pen restorers in general, and the professionals who repair a large volume of pens in particular, have found an alarming increase in failures of sacs in the last several years.  In our experience its frequently, and one could say usually,  related to the inks used in a pen.  You can argue 'till you're blue (or red if you're angry) in the face about it, but the connection is there. 


I was talking to one rather responsible young man at the Raleigh show about it who has been running some experiments with Noodlers and latex sacs.  Not all Noodlers colors kill sacs, but he says that there is a definite connection between the super saturated inks and sac failures.  I don't give his name because he isn't done with his experiments and hasn't chosen to release his results publicly yet. 


I'm a little more liberal than Brian in my ink recommendations.  I/we suggest using an ink made by a pen manufacturer.  I have had good results with Pelikan, Sheaffer and Aurora.  The exception is red ink, or ink containing red (meaning red, purple and brown) of any manufacturer including Omas and Sheaffer.

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#6 aurore



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Posted 30 November 2019 - 20:50

Did anybody try GvFC inks (Cobalt and Midnight blue) in vintage pens with rubber sacs?

Also tagged with one or more of these keywords: rubber, sac, bulb, high-maintenance

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