Someone recently told me a properly restored Vac-Fil pen will only last for 120 fillings before it needs repair again.

Can someone here confirm or deny this, and if it is not true, provide a realistic expectancy for the lifetime of a restored plunger fill.

I'd like to know how "someone" quantified this assertion. Did they do so experimentally, or was this some kind of rough guess?

Given a fluorocarbon rubber (flubber) packing seal and a polyethylene head gasket, I'd guess that a properly restored Vac-Fil could last for decades without service other than normal flushing and common sense care.

Here's part of what David Nishimura has to say on the subject of Vac-Fil restoration longevity (quoted from his vintagepens.com website:

But given that the original packing units typically lasted decades, and that fluorocarbon rubber seals have an estimated life several times longer than the rubber seals used in the original packing units, it will probably be a long, long time before a newly-repaired packing unit will have to be opened up again...

I hope David doesn't mind me quoting his thoughts here; I do so because they are succinct and to the point (and sometimes I'm not).

So, how does one quantify "fillings before service needed"? Does this take into account average flushing, continuous use, fills per week (or month, or some other period). How about the quality of the "proper" restoration job? There are many variables, among them being the quality of the seals used in the restoration work and the attention to details like tightness of the piston head cone, gluing of the hard packing washer and such. All of this assumes that we're talking about the same kind of "proper" restoration job. At one point in time, "proper" was considered to be a red rubber plug glued into the barrel above the original packing and a replacement rubber head gasket (a workable solution ten years ago, but not a very good one now). There's also Francis Goosen's Fountainbel cartridges, which many would consider "proper" (I like them more for pens with special needs, but they do work well and should last a very long time). There is at least one very respected restoration person that replaces the original packing with cork and soft rubber gaskets, and does so from the back of the pen. (Side Note: this is a good reason to join the PCA and read the PENnant - you learn stuff like this). I've heard rumor of other folks that use felt and soft rubber (just like Sheaffer did), but I've not seen a pen restored this way nor talked with anyone personally that uses this method.

My guess is that each of these methods has a somewhat different life expectancy, with the longest ones being those two that use flubber o-rings to replace the packing units, or perhaps the cork method.

Sorry if this is way too much information. You may have just wanted a "yep, that's right" or a "no, that's b.s." kind of answer. It's a good thing to discuss though. I'd like to help people just learning about this stuff to understand that "proper" restoration of Vac-Fil pens is of as high or higher quality than that of any other vintage pen restoration. My opinion: A Vac-Fil restored using current "best practice" methods should last longer before requiring service than anything with a sac in it and at least as long as any well-made cork or poly piston filler. The only pens that should last longer before requiring service are eyedroppers.


Cheers,
Tom

Good enough for me!

By proper, I was referring to either Ron or Richard, knowing that they are authorized repair centers.

Polyethylene? I seriously doubt that's a satisfactory material; it cold flows, and it's too stiff to flex and "flip" the way a Vacuum-Fil washer is supposed to do. (Check the anatomy description and cutaway drawings here.) Ron Zorn and I are both using a very carefully chosen synthetic rubber with a high durometer and a tightly controlled thickness. It won't cold flow, it doesn't hydrolyze and fall apart under exposure to ink as urethane will do, and it's flexible enough to flip but not so flexible that it'll pull off the piston head. (Father Terry's washers were notorious for stretching and pulling off.)

I consider a proper restoration, as Ron and I are doing this work, to be durable enough that it'll outlast me.

I have also invested in the material which Richard refers to and will be testing my first pen restored with this material tomorrow.

Cheers,
Sean

If by proper we understand "historically correct" then yes, the lifespan of a vac fill pen is greatly reduced by the fact that the plunger loads the packing unit sideways ALWAYS at the same place. Cork and rubber from that era, no matter how delicatedly pampered, would compress and eventually develop a leak. Also the side load on the gasket will eventually bent out of shape the washer, preventing the action from being efficient enough even if the packing unit doesn't develops leakage.

one more reason for going with Francis Goossens "fountaibel" cartridges, moder rubber tech plus the O rings have greatly reduced contact area and still seal better than cork and rubber, and having a circular section they're less prone to suffer from side load deformation.

You appear not to understand how a Vacuum-Fil was made or how it works.

Sheaffer used felt for packings, not cork or rubber. It fails not due to lateral compression but rather due to being allowed to dry out with ink in it; the ink binds up the felt fibers, rendering them stiff enough to break when the plunger is operated. When the fibers break, the packing leaks. The flubber O-ring that we're using to replace dead packings is rated for the duty it's being subjected to.

There is no side load on the gasket. The feed does not begin to push the plunger head sideways until after the gasket has cleared the bore and emerged into the larger-diameter space at the front of the barrel.

I've handled Vacuum-Fil pens that have their original packings and gaskets, and they function perfectly. Why? Because they were flushed completely before being set aside.

I have original packing units that have felt, cork and a thin rubber (wild guess: the same rubber as the plunger's) on top and bottom. And plunger is pushed aside at the "fat" portion of the bore, nevertheless the backing washer touches the barrel in this operation, and the rubber compression gasket is larger than the backing washer. I respectfully disagree with you here. Plus, felt per se would not seal, it has to be impregnated in some kind of oil. Oil would repel ink for some time.

The only OEM packing units that I've handled that still work nowadays were always stored with water inside and operated from time to time. Water keeps the cork and other packing elements moist and within a plastic range of size (they are allowed to take bigger shape stress).

This is ought to be another mistery for me as the 5 slots P51 clutch, never seen one, as I never ever saw one all compressed felt packing unit on a vac-fil. felt and rubber, felt, cork and rubber, never ever handled one single unit that was the cartridge all filled with compressed impregnated felt.

Richard,

Didn't mean to chafe your hide... I pulled "polyethylene" out of my (faulty) memory rather than looking up the proper name of the material. Yes, I just looked up polyethylene and that's not it. Believe it or not, even I wouldn't cut Sheaffer Vac-Fil gaskets out of old plastic shopping bags...

I'm currently using the clear gasket material that David Nishimura has been selling for the last year or so. What is that stuff called, anyway? DN appears to no longer have this material for sale. (David, are you out there?)

I cut my own head gaskets with a set of custom punches, designed specifically for the task (thanks to F.G.). So far, the material DN has been selling is the best I've found for this application. It is durable and flexible, but not so flexible that it will easily pull off like the gaskets that Fr. Terry (bless him) and later, Victor Chen, used to punch and sell. It also cuts very cleanly, so it is fairly easy to make a high quality gasket with no stray bits hanging off the edges. A good set of punches insures nice, concentric cuts (which was the other limiting factor with Fr. Terry's gaskets - the center hole was rarely right in the center).

I've been restoring Sheaffer Vac-Fil pens by replacing the original packing with an o-ring for about 5 years now. Fluorocarbon rubber o-rings are certainly the best so far. The clear sheet material (what IS that stuff called?) that David Nishimura has been selling is the best solution for the rod head gaskets I've seen.

So, my question to you, Richard:

What's the name of the "very carefully chosen synthetic rubber with a high durometer and a tightly controlled thickness" material that you and Ron are using and where can I find it? I'd like to try it.


Cheers,
Tom

You should stop using it immediately. That is urethane, and David is no longer selling it because he and Ron and I have learned that it hydrolyzes when exposed to the majority of current FP inks. (The data sheet, according to David, did not fully describe its properties.) The failure mode of hydrolysis is catastrophic; as it absorbs water from the ink, the material expands and becomes soft, eventually tearing itself into pieces that look as if the part had actually exploded.

Ron and I will be selling our rubber at, and after, the DC show. We've priced it so that it is very inexpensive, costing less than 10¢ per gasket if you cut carefully.

I'm going to chime in here, having been off line yesterday...

I have yet to see any pens with cork as the OEM packing material, including NOS and near mint pens. IF Sheaffer used it, it certainly was not used in the majority of packing units and was not a standard material.

I discovered the problem with the urethane washer material back in February, and began to run some tests to identify the source of the failure. I was able to repeat the same failure in the same pens within a month or two. At that point I started a test in inks to see if it was ink related. I also started a search for a replacement material and passed on my observations to David and Richard.

in the process of doing my search, I spent quite some time talking with people in the rubber industry about what material to use. Out of that discussion came the the key to the failure of the urethane - the fact that it absorbs moisture. When it absorbs moisture, it swells, then looses it's tensile strength and tears. It's not in the product literature - but it's something that only an individual who has worked in the industry for years would know. The guy who told me about it had seen it happen before.

The material that I found and that Richard and I now use is a high grade synthetic rubber of a non-standard thickness. Chemical resistant, wear resistant, and tough. I've contacted vendors from all over the country, and can assure you that you will not find rubber in the right thickness, hardness and material in standard rubber stock from anyone.

I'm not aware of any plunger-fillers that use just plain felt as a packing material, but there are examples that use cork -- Onotos being the prime example.

The problems with the urethane seem to appear only after very prolonged immersion. I've had samples soaking for months without any visible deterioration, and others in pens that have held up for at least as long. At the same time, there have been pens where problems appeared more quickly, which it would appear would have to do with other ingredients in the ink used. What still isn't clear is if the problems can be avoided by giving the pens a periodic rest to let the urethane dry out. It's possible that when moisture gets into the material, it doesn't come out again so easily.

Just to clarify (so we all understand what pens and materials are being discussed) - the OEM packing units for plunger or vacuum-filler pens were:

Onoto - Cork

Sheaffer - Alternating layers of grease-impregnated felt and rubber washers, with a hard closure washer?

Wahl-Eversharp - ?

John

back when I joined the board, I mentioned that I was using a very thin synt rubber with great success, with a thickness of .005" and .003", you all chimed in suggesting Urethane, my answer was "I hate uretane .... besides it doesn't do any good as in improving filling capacity or action or smoothness and it doesn't lasts". Are you using nitryle rubber as I mentioned before (as in about a year before???) ? I don't want to be rude or nasty, but I feel that saying "a very thin synt rubber in a controlled thickness..." instead of putting a name to the product is vague and kind of makes you guys look bad compared to i.e. francis who has posted names, blueprints, specs, brands, materials by their names... It sounds like you're trying to keep the big secret of what kind of rubber you use from being discovered by the general audience. That's of course my 1 cent (less than 2 cents! ) and I don't mean to disrespect any of you whom are involved in the misterious developement of very thin rubber cut into head gaskets for vac-fil sheaffers.

This isn't what we found. I've seen urethane failures in pens sitting in my cabinet for a few months dry and empty after having been used for only a week or so. Ron kept a gasket immersed completely in ink continuously for four months without failure. In that same pen, in the same ink, in actual use (which involved filling and emptying), failure appeared in six to eight weeks.


Paraffin-impregnated cork, actually.


Not alternating layers. A rubber washer, two layers of greased felt, another rubber washer, and a celluloid closure washer.


Same materials as Sheaffer, but a thicker packing.

We experimented with the materials Ron researched to determine the right combination of properties for this purpose. The material we found best is the stuff we're using, a high-grade Buna-N. We are in the business of repairing pens for a living. We're happy to provide the material for others to use, but we feel that we are entitled, without apology, to recoup the considerable investment of time and the expense involved in finding and procuring this nonstandard material.

Richard, Ron, David,

Sure, I'd be glad to try a more resilient material. Let me know how to buy some and I'll place an order right now.

I've had no problems at all with urethane gaskets. I've had several pens with urethane gaskets in daily use, inked now for over a year, and several others in and out of the rotation during that time. All are performing flawlessly and none show any outward signs of deterioration after using a variety of current and vintage FP inks in them.

I carefully inspected two of these this morning that have had ink in them for the longest periods (> 1 yr.). Both urethane gaskets look and feel just like they did when I cut them. If anything comes back from a customer, I'll gladly be doing some free restoration/warranty work. If I'd seen the kind of problems described above, I'd have quit using urethane too. As soon as I have something better available in my shop, I'll use that.

Urethane has been the best material available so far. Richard and Ron, you two have been using urethane gaskets as well, yes? How many pens have you had returned from customers? Do you have any pictures of deteriorated urethane gaskets? Let's have a discussion about this rather than a sales pitch backed by statements that make it sound like the sky is falling, please.


Cheers,
Tom

as I said richard, just typing out loud, not actually demeaning you or ron or any other pen restorer. Every now and then an outsider like me or francis or any other mechanically inclined board member is bound to have a better idea, just because we DON't do pens for a living and we approach the pen business as a kid playing with toys. Buna - N is nitryle rubber, it's standard down here in Argentina and that stuff is made in the contry and exported and some thicknesses are imported from europe. It won't disintegrate with acids, fuel, most solvents, etc. Is a top choice. When I suggested it many memberst told me I was outdated and that I should try urethane...

I won't be selling the stuff or depriving you or other pro pen restorers from earn a living if we call it by its name. Actually the information may be widely avalible and that would not hurt the pro practice, because you charge for your miraclous hand and not by the state of the art top notch secret materials you use. In woodwinds restoration (what I do for a living) many colleagues feel as you wrote, entitled to [...] I choose to spread out information because A) there's only so many saxophones or clarinets I can actually fix and schedule for a high quality all in house restoration like I do the more information (accurate information) the most old saxophones that will live on thru the years, actually providing for me in a potential future C) more mistery you create about something, it ends up turning against the pro practice of that certain proffesion because people feels scared to use the object because maintaining it or restoring it is "so expensive and misterious and only 3 people in the world know the right type of (-----)" (insert any pen or any sax or any object's pieces name here and it would serve to my example)

There's only so many pens you can get hands to before either your turn around times are unacceptable or you start to slip under constant duty pressure or else... this comes from a guy who's know because certain particular instruments took about 3 to 4 years to restore from top to bottom.!!! Some customers did wait for about 2 years for me to lay hands on their horns when I had surgery recently!

I believe that one thing's trade secrets and other thing's information. while I don't share trade secrets, goods brands and names and suppliers, information about how to-s and such I'll happily provide (and I'm not talking about pen restoring here because I only restore pens for having a second occupation to wich I ressort when I'm beaten and I can't stand to take a peek at another dented saxophone or cracked clarinet for about at least one hour or so)

I decide to provide information so more people would be able to have elements to judge the ability and credentials of my competition, rendering the bad, the ignorant and the hackjobs that charges 25% of what should be a decent fare for any particular job and what's worse they ruin perfectly good instruments while they're at it, easily spottable for the average customer. I reveal what brand of pads I use, where I buy my goods, I charge for my years of expertise and the level of accomplishment (or not!) that I have when I'm at doing american woodwind restoration (wich is what I do for a living). I see your work and I'm convinced that you charge by your level of finesse and not because you found a super-duper secret rubber or a sac that's so thin that would hold 6 times the amount of ink that those used by (other pen restorer's name here)

There's only a given amount of pens you'll restore from now on to the time you stop doing pens. Revealing the name of the Buna - N will not drastically increase this number (if it changes any). Same goes if you add Ron Z, Rick Propas, name all the pen restorers you want. You (we) can't fix them all. That's my 2 cents (one from before and the one from this post.)

The sky is not falling. It has already fallen. I've seen perhaps half a dozen of my failed pens returned for warranty repair, one of them having returned twice because my first analysis of the probable failure mode was wrong. I have developed a list of more than 70 pens I restored with urethane, and the people who sent the pens to me will all receive a recall notice after I return from the DC show. Repair will be done under warranty regardless of when the work was first performed.

I don't have any pictures of deteriorated gaskets, but I can describe what I've seen. The first sign of deterioration is a darkening, caused probably by the absorption of some amount of dye. Darkened washers have swollen and become soft, the amount of swelling and softening determined by how long the pen has been in use. Failed gaskets come out in pieces that look almost as if they had shattered.

You can buy the rubber from either Ron or me at the DC show, or from our Web sites after the show. I'm too flippin' busy getting ready for the show to put up a new page for the gasket material before I go.

I am one of the people on this forum who benefit immeasurably from your and Ron's expertise that you share so unselfishly. In my opinion, you are definitely entitled to recoup as much of your R & D cost as possible. Thanks for all you do for all of us. /Craig

You want a picture of a failed washer? Here you go.



The brown bits on the left side are the remaining pieces of a failed washer. A piece of a urethane washer is on the right. Same material, one in a pen that saw ink, the other never having seen ink. I saw this first in one of my own pens, saw it happen in the same pen, and have seen it in several others since then. It may be the particular grade or brand of urethane, but the folks that I talked with were not at all surprised to hear that it had failed.

The problem is that Sheaffer used a graphite impregnated rubber in the washers. The graphite acted as a lubricant so that the washer could slide down the barrel wall more easily. (more on that below) Nobody makes that today. It no doubt can be made, but how do you determine how much graphite to use? What grade? And then there is the minimum run required to have it made once you've worked out the details. The cost for a run far exceeds the limited need, and can not be justified.

Another problem is that the definition of buna-N, or neoprene, or other rubbers is that you can have different grades of the rubber with the same name. You have to ask what grade you are getting and what the source is. In this case I was able to find a limited supply of a high grade buna-N, with the right durometer, the right thickness, and which provided the right friction on the barrel wall. Finding the combination is very difficult indeed. I invested time off and on over the better part of a month tracking down the material. Then Richard and I tested various samples in pens and concluded that this is the best available. Indeed, it's the best I've ever used. Pens that filled maybe 2/3 to 3/4 of the way with urethane and Viton fill almost completely full with this rubber.

Let me stress again that nobody knew that urethane could or would fail in the way that it did. All of the information that we had suggested that it was the ideal material for the piston washers because of it's resistance to chemicals. As a matter of fact, I held off repairing the pens until we came across the urethane, because I didn't like the feel and performance of the Viton. I didn't believe what I was seeing when I found that the washer had failed. But when it failed a second time in about 6 weeks time, I knew that we had a problem and immediately quit using the urethane.

The test with sample in ink (which is the same as used in my pens) did not fail. But the washers failed in several pens.

We did try Viton, but found (as have others) that it is too stiff, and that there was much too friction on the wall of the barrel. You can't lubricate the barrel to make it slide more easily with silicone because it prevents the washer from flipping back as it should on the down stroke.

Ron,

Thanks for the picture! This is helpful. I've never seen anything like this, but now I'll know more or less what to look for. Can you tell us more about the failed washer? How long was it in a pen? What kind of ink? I notice some staining on the "uninked" washer. What's that?


Cheers,
Tom

You'll find some answers in the edited post above. I suspect that the brown stuff on the intact washer is either residual ink, silicone grease (which I no longer use) or bits of washer that didn't come out of the pen. I took the picture a few weeks ago, and threw out the bits after I was done.

It doesn't seem to matter what the ink is. In my case, I was using vintage Quink, but the urethane has failed with other inks. Richard uses modern Waterman blue/black ink. Note that I had a piece of urethane sitting in a bottle of ink for nearly three months, and it didn't fail. But it did, dramatically in a pen! I also put shellac and silicone grease on areas of the sample in the ink. No change at all on the shellac side, a little change on the side with the silicone grease.

The breakdown was most dramatic in pens that were filled and used, allowing air into the pen along with the ink, or in pens which were use, and then cleaned out and allowed to dry out. i.e. real life conditions!

The failure mode is just what you see in the picture - the urethane turned dark, lost all tensile strength and shredded when you tried to fill the pen. Where a good piece of urethane will simply stretch, you could pick off pieces of the failed washers. There was also some swelling, though I did not measure the change in thickness.

too bad jessy K must have traveled by now, but if you guys provide me adress, I will ship a couple of samples of the nitryle rubbers (Buna-N varieties excluding those wich has a mesh reinforcement in the middle) I can find down here, along with some other speciality rubbers in sheets I know a company makes (I don't know if the thickness is right but I can find out soon)

urethane indeed fails. I commented about this a year ago! that the washer didn't last long. I didn't know the cause was hidrolysis back then but I suspected some sort of mech stress combined with ink... but since board members said I was outdated by using multiple layer head gaskets and that high tensile stress rubber, I just shutted up and let the pros go on about that. I don't like urethane in nothing, not even on what's supposed to be good, that is improved handling street suspension components. I would rather use poly but NOT on head gaskets (piston seals are OK with poly).

Another issue that would be interesting to investigate if the amber (clear) urethane behaves the same as other colors. In my experience red dyed urethane is OK for vintage german piston fillers seals replacing, but I don't know if besides the red color the factory does changes anything else in the composition of the rod.

Ron,

Thanks for the well thought out and helpful response. I'll be checking the rest of the pens in my personal collection for this failure mode, and will be replacing all of the head gaskets with the buna-n material. My Vac-Fil restoration customers will get an email from me offering free replacements as soon as I've got the new material. It's interesting that you've found that exposure to air might be a factor. I haven't taken apart any of mine that have been used, flushed and put away, but will be doing so this evening. They've all seemed okay from the outside, but now I want to look at them up close and personal.

I'm still interested in quantifying the failure rate for urethane gaskets, but as David Nishimura mentioned back channel (I'm paraphrasing), even a few are too many. I suspect we won't really know for a few years, but I hope it's not a repeat of the gooey sac fiasco from a few years ago. Sounds like it could be.

I understand that you (and others) earn your primary income with your pen restoration businesses, and appreciate the time and thought you've put into finding a better material. Vac-Fil pens have been an evolving restoration challenge for over a decade and it's been good to watch and participate as the methods have improved. I'm looking forward to trying the new material as soon as possible. PM on the way...


Cheers,
Tom

Hi all,

jicaino, I like the way you think and I agree that the boys with the new toys should share, but that is just how they think - not not knowing the good deed would be come back to them many times over. It's kind of like the way the world is run these days

I hope you all test the plunger head gasket material thoroughly, before putting it out there for failure or not, this time. I will be interested in the results of your tests. When you get conclusive results, I would like to see it posted in places like the Zoss List, Pentrace and here.

Have a good show in D.C.!

Michael

We are Mike. Read the posts above carefully.

The rubber that I bought is an oddball size, and has the right properties for the washers. I bought all of the stock that the vendor had. Not to horde it, but to insure that those who do repairs would have access to the material because it's not easily duplicated. There's more there than enough, and so we intend to sell a fair bit of it, but certainly will not give it away. We'll have it on our web sites after the DC pen show.

I would like to point out that there are plenty of people with what may be considered to be proprietary materials out in the pen repair market, who share neither their sources or the details of their product. I respect their right to profit from their efforts, and would request the same in return.

It would appear that the discussion regarding sharing of details regarding the new gasket material has reached the limit of usefulness.

Ron and Richard have fully discussed the acquisition of the material, their decisions and reasons for those decisions on how to offer the material to the pen community, while the proponents of full disclosure have had their say as well.

As I believe that further discussion would not be helpful, I am requesting that no further posts be made on that aspect (and will remove any that are made).

The VacFil thread will remain open for continuing discussion of washer failures, repair experiences, techniques etc. for everyone's use and enjoyment.

Thanks for your cooperation in advance.

Regards,

Gerry
Repair Forum Co-Moderator

Well, it is evident that with this new material, washer failures should not be a problem. So thank you everyone who posted, this has made up my mind that I should buy a vac-fil.

~George

I just finished my first plunger fill restoration with the new material, and I am impressed. I restored an OS Balance for a friend and actually waited till I had this material to cut the plunger washer. After installing it into the pen, I was surprised that the pen would actually push the plunger all the way up if I did not let it break vacuum at the end of a stroke. It didn't just slowly push it back into full extension, but rather snapped it back forcefully all the way. I will be doing a fill test tonight on it, as I thought it best to let the sealant (Ron's new formula) setup for the night. It is not a requirement of the sealant for it to be left that long, but it was getting late and bedtime stories also needed to be read for my daughter.

The material is easy to cut, and even to trim if needed. I found that I had a small defect in the cutting surface of my punch and had a little tag to remove to make the OD "perfectly" round. A little trim with some sharp scissors and all was good.

The material does cup well and snaps over when the vacuum is released at the end of the stroke, and as there has been extensive testing done on the rubber, I am not concerned with sending it out to clients.

Thanks Ron for bringing this material to market.

As an aside, I am probably one of the only people at the moment who has this material other than Ron and Richard, but that is only due to happenstance. I was talking with Ron and he mentioned the issues with the old material, and that he had tested this new stuff. I asked if any was available and purchased a yard as soon as I could get the paypal out to him. It was a happy coincidence that I was discussing it with Ron when he first got it in, and was able to purchase it immediately.

Cheers,
Sean

Richard and Ron:
I'm not a pro, but I've done about 300 Sheaffer plunger-filler restorations, and here's something interesting I've found regarding the piston washer's operation that MIGHT explain why you can have a failure within a pen but not not in a bottle of ink. In the late 1930s, Sheaffer patented the feed with the long "tail" to push aside the piston head near the end of its closing motion. BAD IDEA! When screwing down the blind cap after filling, the rod washer abraids against the very sharp hard bubber "tail". Do that several times and here's what happens. First, the washer might be pulled off the hard backing washer and over the closing nut. Second, the sharp "tail" will simply tear the washer. Could this be the "deterioration that you and Ron have found inside the pens, but NOT insode ink bottles? As you know, Sheaffer eventually put their blind cap on a gimble. Am I pushing it a bit to think that they did so in order to avoid the "deterioration" of the rod wahsers? Inquiring minds want to know. I, for one, have adopted the practice of shortening feed tails when I repair a plunger-filler, and I have never had a "deteriorated" rod washer.
See you in DC.
Gerry Berg


edited to make the quote more obvious

One of the properties of urethane is it's resistance to abrasion, so hitting the feed should not be an issue. I suspect therefore that the differing rates of deterioration has to do more with complete and continuous immersion vs. exposure to air and moisture than it does with abrasion.

The problem with a short tail on the feed is that it then can't do it's job. As you said, the knob on the end of the rod that holds the washer on is designed to hit that tail which pushes the rod to the side, breaking the seal between the washer and the barrel wall. There may be enough of a gap without it to allow the ink to be drawn in by the vacuum, but the surface tension of the ink can prevent the ink from flowing down to the feed. You then have to play with the pen to get it to write again. I can see some validity in rounding off the sharp edges, but I think that shortening the feed will create problems.

Wahl used a rod that ran off center from section wall to section wall to do the same thing. Sometimes it was made of stainless steel, sometimes of hard rubber. But the principle was the same - push the rod to one side so that the ink can flow. On some of the early versions made by Sheaffer, there was a lock nut on the back end of the rod in the blind cap. This allowed you to adjust the penetration of the rod so that it would hit the feed just right. They eventually went with just the threads in the blind cap, and then what I call the "woggle" blind cap with the cartridge type of vacuum fillers. BUT, they also had several different lengths of rod so that they would get the depth of penetration right with less chance of it being screwed up or adjusted wrong.

According to David Nishimura, the problem with the washer pulling off around the nut is a problem of rubber hardness - i.e durometer,* rather than the washer getting dislodged by the tail of the feed. The lower the durometer, the softer the rubber. If you get it too soft, it'll stretch and pull off. The other issue is the thickness of the rubber. Look at the washer end of the nut- it has a shoulder that fits down through the washer and then stops against the backing washer. After some consideration and experimentation, I had to conclude that if the rubber is too thick, it has to compress when you tighten down the nut and cups too much. It then is easier to for it to slip off of and over the nut when you pull the washer back. Too thick and you also run into the problem of extra friction against the barrel wall, which means that it can't flip back as you push the plunger down.# Too thin, and it you won't have enough resistance to get a good fill.

You can see then why not only the rubber material, but also the rubber's durometer and thickness are important. The unique combination of these three parameters for the washers, is what makes finding the rubber difficult.

* if you want a quick primer on durometer, take a look at the article on Wikipedia. FWIW, hard rubber has a durometer of 100 on the A scale.

# an issue that I had with using Viton. Even though the durometer was in the right range, and it was only a few thousandths too thick, there was too much friction, and the washers tended to pull off and over the nut besides being very stiff on the downstroke. The big advantage to Viton is it's resistance to petrochemicals, which you shouldn't have in a pen. The cost, about 5 times that of a high grade buna-N weighed against the very marginal advantages eliminated it from consideration. I still have the rubber sample......

Thanks, Ron. That's helpful.

I really don't think that pushing aside the rod on the downstroke actually does allow ink to flow more freely around the washer and into the barrel. I've tested dozens of these with and without "tail", and I find the same filling volume can be had without the long tail.

The question of blocked ink flow is potentially a more serious issue. Here, however, I have found that a moderate "tail", rather than a long one that acutally touches the nut, produces the desired ink flow while writing.

I was fascinated by your discussion of the thickness of the washer and think you are right on the money there. I have found in addition that shellac on the backing washer (a no-no in Da Book et al) cradles the flexible washer nicely. Add a dab more shellac to the nut itself so it flows out very slightly onto the wahser, (almost?) entirely eliminates the problem posed by the washer pulling off. I have founded easier to use Victor Chen's washers than to cut my own. Are they Viton? He's never revealed the material, but I do know that the material differs from whatever Father Terry used, and that the washers are punched with far more precision than Fr. Terry's.

In any case, I will be stopping by your table or Richard's to buy some your stuff for experimentation. If I can figure out an easy way to cut the washers, I may use that material. I will have a table at DC. Please stop by if you get a chance.

Best,
Gerry Berg

Hi Gerry,

The best tools I've found so far to cut these washers are the punches made by the very talented and kind Francis Goosens (fountainbel, here on FPN). Francis sells his punches in a set of three (one for each washer size). They are very high quality, easy to sharpen, and perform really well, making a nicely centered rod hole. They're priced very reasonably for high quality custom pen restoration tools. Mine quickly paid for themselves because of the accuracy of the cuts they make. I don't ever through away washers now, and all pens fill better with a really well formed head gasket.


Cheers,
Tom

Thanks, Tom

Francis punches are made to cut the washers to precisely the right size, with a center punch that is really on center. Unlike the washers you get with other punches that give you washers that are the Hitch Hikers Guide tea.....

Hi all,
First of all I want to thank Ron & Richard for shearing their experiences & offering an alternative for urethane.
The fact urethane hydrolyzes surely makes it suspicious for making our piston seals.
I also ordered the Buna N material from Ron
Till now I never experienced a problem with Urethane piston seals & surely never experienced a seal that was completely teared apart!
I think Gerry brought up a very interesting viewpoint on the reason why the piston seal can be teared apart in pieces.
Just checked some vac-fill's equipped with the extended feed finger and found there are indeed potential risks for axial contact between the finger top and the piston washer .
The cylindrical part of the piston seal enclosure nut slides up to 4mm over the top of the finger.
I've also checked several feeds with the finger from my spares & measured "untouched" finger lengths varying from 6.1 to 6.7 mm.
I also found several feeds on which the fingers which reduced to 5-5.5mm . These were ground off & made with a conical entry;
I wonder in how far this was done by Sheaffer in order to cope with length variations within the parts influencing the axial end position of the piston.
Measuring 3 pens I found one on which the piston seal effectively touched the finger top, on the 2 others the seal remained at 0.3/0;4 mm from the finger.I also measured some original piston rods & found length variations up to 0.5mm.
Equally the blind cap coupling nut on the "floating" blind cap may vary up to 0.5mm in length.
Remarkably I also found barrel length variations up to 1.0 to1.5 mm between 2 different pairs of identical pens!
All these tolerance variations logically influence the end position of the plunger, and request a very close control of the end position of the piston seal versus the finger top.
The risks for shearing the seal in pieces at contact with the finger are logically much higher on the fillers having a radially fixed blind cap.
So I would expect Ron's findings on the sheared piston seal most probably occurred on a pen with a radially fixed blind cap ?
On these pens the seal rotates while contacting the finger and "bites" in the axial slot of the finger top.
In the end this logically results in shearing the piston seal in pieces
I expect this is one of the reasons why Sheaffer changed the design the the floating blind cap, whereby the piston seal is at least not rotating at contact.
Note some fixed blind cap pens are also equipped with an adjustable counter nut on the thread of the blind cap piston rod.
This was in my opinion equally done allowing axial adjustment to avoid axial contact between the piston seal & the finger top.
In my opinion Gerry is right when saying the extended feed finger is not necessary, I've equally repaired several pens without the finger and found these filled equally well.
A supplementary reason for introducing the "floating" blind cap on the later vac-fill's was most probably avoiding "over constraint" -hence bending of the rod & deformation & leakage of the rod seal- when screwing the blind cap and pushing the rod sidewards against the extended feed finger.
That's it folks, just my 2 cents, thanks for reading so far !

By the way, I've just tested a prototype of a new plunger filler piston seal which uses an off the shelf O ring instead of a washer.
The O ring - mounted on a cone- is axially floating on a new made piston head.
Doing so I obtain a check valve function, allowing free return flow of the ink (avoiding pressure build-up) when pulling the plunger out.
I designed this system for my own plunger filler, and - applying one filling stroke- I am able to obtain a filling rate of 90%.
Used in combination with my plunger rod cartridge, the benefit being that all seals are standard "off the shelf" O rings which can be replaced from the blind cap side in 5 minutes.
I will shortly also make a version for an OS Sheaffer, although I'm sure the "purists" will not accept this approach.

Cheers, Francis

Just a note for Ron.

I have had experience of buying quantities of neoprene type materials for one of my jobs where the exact composition and hardness was critical for its durability in the environment I wanted to use it in. I found the perfect material, tested it and confirmed it would do the job perfectly. All fine & dandy.

Two years later we wanted to repeat the job, went to the same supplier, same brand, same material, same spec and everything. Did qualification tests on it to prove it would work with the new batch. Well, the batch composition was so different from the first that it was difficult to call it the same material, and its life in the environment I needed to use it in was 1/50th that of the first material. Consequently, it was completely unusable, and I couldn't find a suitable replacement. In the end we changed the design so the composition was less critical - at considerable expense and delay.

What I'm trying to say, in a round-about manner, is that unfortunately you'll need to do all your tests again when you run out of the current stock. Going back to the same supplier for the same material will not be enough.

Regards

Richard.

Very interesting, Francis! You are one creative fellow... I'd love to see a picture of this whenever you're ready to share one.

I think your thoughts about contact between the washer and the feed tail, especially in pens with a fixed blind cap are spot on. Some pens have obviously broken feed tails, but also many that appear to have been modified specifically to keep the tail away from the washer. I've never measured these the way you have so I'm a little surprised to learn about some of the large variables in the various critical lengths. I've never counted accurately, but there must have been ten or twelve "standard" lengths of rods used over the years. I've noticed the length differences caused by the fit of floating blind caps, but the other variables constitute helpful new information for me. It's something good to keep in mind while working on them, so thank you for sharing! I suppose one last variable would be insertion depth of feeds in open nibbed pens that don't have a feed seat in the section (or a feed/nib collar).

I agree that the feed tail is not needed for filling purposes. These always fill well without a feed tail. However, some require a lot of fiddling to allow ink to flow back to the feed for writing (like Ron pointed out). I've had one or two without feed tails that just would not allow ink to get to the feed, no matter what I tried, so I had to replace the feeds to deflect the piston head gasket so they'd write correctly. It's interesting/strange to me that it's sometimes more difficult to overcome this problem (of surface tension of the ink causing a barrier) in Wahl/Eversharp rod fillers, even though they have rods that are easily axially adjustable.


Cheers,
Tom

Hi Tom,
Thanks for the compliment on my new piston seal, I'll post some pictures after evaluating the system 3-4 months


[quote name='Tom Pike' date='Aug 7 2008, 08:23 PM' post='694812']
I agree that the feed tail is not needed for filling purposes. These always fill well without a feed tail. However, some require a lot of fiddling to allow ink to flow back to the feed for writing (like Ron pointed out). I've had one or two without feed tails that just would not allow ink to get to the feed, no matter what I tried, so I had to replace the feeds to deflect the piston head gasket so they'd write correctly. It's interesting/strange to me that it's sometimes more difficult to overcome this problem (of surface tension of the ink causing a barrier) in Wahl/Eversharp rod fillers, even though they have rods that are easily axially adjustable.

Thanks for shearing your experiences Tom,this is very interesting.
I expect the diameter of the piston seal is a critical issue, specially on a pen whitout the feed tail.
I've already encountered repaired pens with a piston seal being 0.6mm bigger as the barrel bore, and these filled reasonably well, at least on a pen having the feed tail.
Ideally the flat "un-cupped" seal diameter should only be 0.20 to 0.25 mm larger as the barrel bore to allow direct
"flipping over" of the seal- hence optimum filling- when pushing the plunger down.
The measured diameter step between the barrel & filling chamber bore is 1.4 mm.
This impleis there is diameter difference of 1.2 mm between the filling chamber and the seal, or a radial gap of 0.6mm, at least when one uses the optimum seal diameter.
Given the design of the filling system I expect the seal will never sit fully concentrical to the filling chamber, even in a pen whitout a feed teal . So on one side the seal/ filling chamber gap could be 0.8mm while on the opposite side (180° further) the gap would be only 0.4mm.
Maybe I'm wrong, but I would expect this gap will allow the ink easily to enter the barrel & to flow to the feed when writing. However when the piston seal is cut to a larger diameter the feed tail becomes more neccesary.
On the other side I fully agree that both ink viscosity & surface tension differences are important parameters which could influence the inkflow in & out the pen.
Not knowing which ink will be used in the pens I repair, I will surely take profit of Ron's & your experiences & install a replacement feed - although with a reduced tail !- when encountering pens with a broken feed tail.

Cheers,
Francis

Which is why I bought all that I could get my hands on. I figure that with the amount that I bought, we can make about 156 thousand of the small size washers. Even if I did 50 pens per day, that's 60 years worth. I will either be dead or very bored.