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Installing a New Diaphragm in a Parker Vacumatic

Tools you will need:

  • Thumbs
  • Talc
  • Silicone Grease
  • Vacumatic wrench/block
  • A brass tube
  • Water soluble lubricant
  • A small, sharp knife or scissors
  • A small drill or Dremel tool
  • Cloth or paper towel

Tools you may need:

  • Section pliers
  • A heat source
  • Masking tape
  • A fine marker
  • Grease pencil
  • Bamboo skewer
  • Small syringe
First thing:  Without the right tools for this, the destruction of the filler is virtually guaranteed.  Luck or miracles (whether of faith or thermodynamics) might see one through safely without the correct tools, neither of which is ever to be counted upon.  Don’t have the right tools?  Don’t try it! I’m going to mention it again at the right place, but this is the basic principle of the thing.  A lot of the other repairs I’ve got outlined here can be managed with tools lying around the house, when tools are needed at all, but this is a case where a specialized tool is absolutely necessary.  I hope I’m clear about this.

Vacumatic fillers are found in Vacumatics, some Duofolds, and in the earlier “51”s.  This latter group, having rather different anatomy than the other pens, has some diversions from the usual routine of repair for this style of filler.  I’ve got the exceptions listed at the bottom, and links to the exceptions at the appropriate places.

The first thing to do is to unscrew the section.  This will frequently call for warming the barrel to release some sealant holding the section in place.  Be careful in this, as the bodies of most pens with this style of filler are made of incendiary celluloid.  If it’s too warm for your fingers, it’s too warm for the pen, and most pens with this filler announce they’re too hot by bursting into flame. “51” Exception #1

I prefer this to the block

Now we meet the absolutely indispensable tool: the Vacumatic Wrench.  There’s a couple of sizes of them, because the fillers come in two different sizes (the pens come in several).  This screws onto the filler, and then clamps onto it so the interior portion can be turned out of the barrel.  There is another tool, the Vacumatic Block, which fits both sizes of filler, and which clamps on not by the pressure of the user’s hand but by tightening of a small screw.  Both work, and both have dangers.  The block can be easily over-tightened, deforming the filler.  The wrench (the more traditional tool), can also be over-tightened, because if you’re very intent on getting the thing loose from the barrel you might clench too firmly.

Deforming the filler is pretty much guaranteed without one or the other of these tools (unless it’s one of the units with a plastic thread, which will just shatter), so if entertaining thoughts of just giving it a try without one, stop now and go lie down for a while.  If I’ve convinced you of the necessity, have a look at some of these links; several sell either block or wrench

Before using that tool, take a moment to establish some registration marks to help get the filler turned back to the same place it currently lies.  This is useful because the barrel and blind cap were smoothed together on a lathe, and they may not be uniformly round but they match each other in their current alignment.  If the filler isn’t returned to its current place, this alignment changes and a slight disjunction occurs; it’s not a big thing, but it really bothers some people.  Make a dot on the threaded collar of the filler, on the flat upper face, with a grease pencil, and use masking tape and a marker to make a corresponding mark on the barrel.  I am not a general advocate for applying tape to pens, but this should be in place for a few hours at most.

Pen mated to wrench

Screw the filler into the removal tool.  Some heat might be needed at this point to loosen up the connection between filler and barrel, either through shrinkage of the barrel (heat will relax it) or some foolish past repair which saw some sealant applied to it (it shouldn’t, but it might). This is a stage at which patience may be needed, since a recalcitrant filler might need several applications of heat to come free.  A truly stuck filler might actually be ink-cemented and need to soak for a bit; don’t soak it too long and don’t leave it sit around afterwards, as there’s a little spring involved that will rust readily and a speedy removal means a speedy drying (which the heat source is also useful for).

Once the filler is turned loose from the barrel, release it from the tool.  With the later sort of plastic-stemmed fillers, this is a ticklish time as the weight of the pen or the tool might fall foul on the stem and break it; be cautious.

At this point, the filler will probably still be stuck in the barrel by its own diaphragm.  If this is the case, push a rod of some sort up from the inside to drive it free: a wooden dowel is a passable choice, but better is a metal tube, and it should be nearly the same diameter as the inside of the barrel. The idea is to avoid putting pressure on the middle of the filler mechanism, which is a cup of some fragility.  An tedious alternative is to use a fairly thin probe, like the blunt end of a bamboo skewer, to press gently many times around the diaphragm/barrel contact area.

Once the filler is free of the barrel, you can peel off the residue of the diaphragm from the collar.  This should be a pretty easy task, as there’s not supposed to be any adhesive involved.  This will leave a little plastic pellet stuck down the inside of the inner end of the filler (in the pellet cup, of course).  This is another point where care is required, as the next step is to remove a hard plastic pellet from a soft plastic cup, the latter of which is not less than 55 years old.  The best thing to do is apply a tiny drill-bit or de-burring tool in a Dremel Rotary Tool (or similar device) to the pellet, disrupt it; lacking the power tool, a hobby knife can be used to repeatedly and carefully stab the pellet until it starts to disintegrate. Use a pin to slip the remains out of the cup after warming to relax the plastic, being careful to not pry anything as the cup will not stand use as a fulcrum.  In earlier fillers, the whole affair is made of metal and life is a little less fraught, but care should still be exercised.

The blue indicates the displacement of the filler in both states.

Measure to the face of the little rib, and remember to allow for the pellet when cutting the diaphragm.

Next you’ll need a new diaphragm, which is never the right size– they are made extra long.  The mechanism of the filler does not stretch the diaphragm, but rather just turns it all the way inside out– resting position has it turned halfway.  So, the length of the diaphragm needs to be the length of the extended filler stem.  Too short, and it will stretch when worked which puts stress on the filler stem and leads to failure of the diaphragm.  Too long, and it don’t take up any more space when extended than it does at rest, and since the filler’s whole function relies on displacement, the pen will fill poorly if it does anything.  Too long also causes problems in that the diaphragm envelops the breather tube, further interfering with filling.  Apart from the usual injunction to measure twice before cutting, I’d suggest erring on the side of too long; you can always remove a little later, but it’s pretty hard to put some back.  For those who like to measure things, the length is usually 28mm ±1mm.

We come to another point where a specialized tool is helpful; a specially-turned rod for pushing the pellet into the cup, which goes by the sadly unoriginal name of Pellet Pusher.  It is possible to use some kind of improvisational tool for this; a finishing nail-setter is almost exactly right, although the conical shape tends to cling to the free end of the diaphragm.  The Pusher is run up inside the diaphragm to press the pellet home, and some care should be taken to keep tool and diaphragm in line with the filler.  I’ve found that dabbling the end of the Pusher in talc before applying it helps to get it loose once it’s done its thing.  Don’t push very hard, and keep the cup warm while you’re at it.

If the pellet cup breaks, there are two alternatives:  Find another whole filler unit from someone that has old pen parts for sale (there’s some sources in the Links) or try fabricating one yourself following the instructions here.

End of diaphragm touches the rib, without covering it

Put a good coating of talc onto the diaphragm at this point.  It will resist your efforts to turn it, and will be the very soul of misery without talc keeping it from sticking to itself.  There’s an other tool shown above, and for this you can use whatever’s handy and of the right dimension, so long as it’s not sharp.  It helps in turning the diaphragm to have some kind of rod of roughly it’s own diameter up inside it.  It will probably be necessary to re-talc a couple of times to get the diaphragm home.  When it is complete, there should be a coating trapped between the two layers of diaphragm to help it move smoothly.

Note that arrow in the picture.  There is a rib on the filler’s collar at that point, and the diaphragm is meant to rest against it.  When reinstalled, the rubber is caught between the filler and the barrel, which keeps it in place and causes it to act as a gasket preventing leaks.  Do not pull the diaphragm up over that rib in the misguided hope that it will stay in place better– all this will do is put stress on the barrel of the pen, which is how you get a broken barrel.  It’s not unknown for some shellac to be applied between the filler and diaphragm, but this is both unnecessary and leads to trouble for the next person to do a repair.

Have a look into the barrel, making sure there’s no lumps of diaphragm sticking to it.  If there are, scrape them out as gently as possible; my preferred tool is a bamboo skewer.  What is important is to avoid gouging up the interior of the barrel, as this can lead to leaking past the diaphragm’s gasket.  This is also a good time to give the inside of the barrel a bit of a scrub to clear old ink; use soft brushes or stick to a cloth to avoid scratches.  It’s entirely possible that the clarity of the barrel with increase with this sort of direct cleaning.

From here, the only real challenge is to replace the filler in the barrel.  This might be a challenge in as much as the diaphragm must not twist as the threaded collar is tightened down, and this is another reason for having the section out; one can peer up the barrel to keep an eye on it.  This is usually not a big issue, since the collar can turn freely around the rest of the filler, but to assist the diaphragm should be lubricated at the leading edge (the fold), and at its cut end where it meets the collar.  Screw the threaded bit in by hand to get it started, then mount the pen in the Vacumatic tool to finish tightening.  It will likely be necessary to dismount once or twice before finish to check the registration mark.  Do not grunt and strain while tightening; the effort should be not unlike putting the lid back onto a jar of honey, with some effort to make sure leaks are averted but nothing rough.

Do not put ANY sort of adhesive on the threads that mate the filler to the barrel.  Shellac, rosin-based sealant, Poli-grip or kindergarten mucilage has no place touching the diaphragm and its mechanism, but the worst place for it is on those threads; it makes doing this repair the next time an absolute nightmare, as the great surface area of the threads provides far more grip than the places adhesives are usually admitted.

Once the collar is tight, pour a little water into the barrel (a syringe of some sort is the best bet here), put a finger over the mouth of the barrel, and give it a shake.  This should rinse out the talc on the ink-side of the diaphragm, which might otherwise clog up the feed.  Pour out the water and, all things being equal, the filler is finished.

Now, put the section in place and test the filler by drawing a barrel-full of water.  The first test is that it will actually do so.  Remember that it will take several pushes to completely fill, a process visible through the clear barrel (“51” exception #2).  Once it’s full, take the point out of the water and wipe it.  If there are dribbles, it will be necessary to backtrack to figure out where the hole is (sometimes even new diaphragms can have a hole in them, alas).

If there are no dribbles, see if one can be forced.  I put the pen in my mouth, filler end first, and blow gently.  Ideally, all that will happen is that the diaphragm will slightly inflate, forcing a drop or two of water to come out the point, and I don’t so much blow as inflate my cheeks.  Next, I reverse the pen, putting the point in my mouth and try again.  This time there should be absolutely no leakage (“51” exception #3).  If there is, something is wrong and it’s time to start over.  If nothing is wrong, put the blind cap on, take the section off, and shake the water out of the pen

The final step is re-sealing the section.  Either shellac or rosin-based sealant can be used, although I (and the majority of experienced opinion supports me) prefer the latter; when the next replacement is needed, it is kinder to both the barrel and person doing the job (“51” exception #4).  It is possible to use silicone grease, although I recommend against it, as idle accidental disassembly is possible (with a full pen!) and it’s really hard to clean off if one decides in the future to go with a more common sealant.  No sealant is no good, as ink will happily escape out the joint.  Dry the barrel and section threads before sealing.  Put a dot or two of sealant on the section threads and screw the section into the barrel, keeping the whole thing warm as it runs home (assuming rosin-based goop).  Use a little lighter fluid on a cloth to clean up any goop that escapes at the joint, and that’s that for this task.

The “51” Exceptions: There are not 51 exceptions.  There are exceptions that apply to the “51”.  Please use you browser’s “back” button to return to the point you were reading:

The patient, as it will eventually look

1 – Removing the section: One is of course removing the hood rather than the section.  The sealant is more usually shellac (although Parker did occasionally use something rosin-based), and the “51” doesn’t mind going into a pot of warm water– the finger rule still applies, though, although if it gets closer to too hot there’s less likelihood of disaster.

Once the hood is off, before pressing on it will save time for later if the top of the collector is noted with some precision.  A bit of masking tape on the barrel just below the clutch ring (which can and should be removed now anyway before it just falls off) and a marker will make this an easy thing to do, and once it has been done, a bit of gentle tugging after a short soak in water should see the collector with its freight of other parts out easily.

Leave off the ring, as it will fall off, but otherwise this is the state of assembly for the filling test

2- Testing the filler, step 1:  “51” barrels are not clear, of course, and it’s a bit of a pain in this exercise.  To test the filler in a “51”, reinsert the collector et alia, and sink the pen in water beyond the joint.  Press the filler until bubbles stop emerging from the collector.  Lift the pen out of the water and turn it point upwards.  Pull out the collector, and tip the water out of the pen into a small glass; work the filler a couple of times to make sure it’s all come out.  This should produce about 1.5 ml of water, which is only about a third of a teaspoon.

3- Testing the filler, step 2:  To perform the pressure test explained above, insert the collector and put the hood back on, although the alignment of hood and point are unimportant at this stage.  Fill the pen, try blowing in either end as outlined above, and likewise react to the results as above.

4- Sealing the hood: While a rosin-based sealant is not absolutely wrong, there is a preference for shellac in this setting.  Put the clutch ring back on the barrel, then slide in the collector and its hangers-on.  Rotate it until it agrees with the little mark made in Exception 1.  Turn the hood onto the barrel, and make sure that the point is actually aligned with the hood.  If it’s not, take the hood off, adjust the collector, and try again.  Then take the hood off once more, and put a drop of shellac onto the barrel threads.  Turn the hood down once more, and watch that it doesn’t pass the point of alignment; the shellac can act as a lubricant and allow the hood to tighten more than it did during the test.

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