Care and Feeding: How to Replace a Pen Sac
| Although I’m in the business of repairing and
restoring fountain pens, I’d be silly to ignore the fact that
some collectors are eager not only to use, but also to maintain and
even repair their pens. Replacing a leaking, ossified, or otherwise
dead sac is among the simplest and most straightforward repairs you
can make, and I know from experience that it's tremendously
satisfying to start with a pen that won't take ink and end with one
that does. This article, then, is my way of sharing that pleasure
with you.
Tools and Supplies First, you need a supply of sacs. No problem. Shown
here, from top to bottom, are My sac vendors of choice are the Pen Sac Company and
Wood Bin Ltd. (Contact information for all the suppliers I mention is
at the end of this article.) The Pen Sac
Company sells a bewildering variety of straight sacs, necked sacs,
tapered sacs, Ink-Vue sacs, and Vacumatic diaphragms.
(“Diaphragm” is what Parker called the rubber doohickey
in a Vacumatic so they could advertise the pen as being sacless.)
They offer a couple of assortments as well as individual sacs. Their
catalog includes several pages of information showing which sacs go
into which pens. (There may be exceptions on a per-pen basis; the
catalog says to use a No. 21 necked sac for a hard-rubber Duofold
Junior, but I couldn’t even get a No. 20 to fit into the barrel
of a Junior I resacked some time ago.) Wood Bin Ltd offers a smaller
variety, but Wood Bin also sells straight sacs made of silicone.
Silicone is sometimes a better choice than latex because it
doesn’t outgas sulfur vapor that can cause some celluloids to
turn brown.
Note that the Fountain Pen Hospital pliers shown here are actually intended by their manufacturer, K–D Tools, for use on automobile spark plug wires. You may be able to find them for a lower price at an auto parts store. If you have a bench grinder, you can make your own section pliers out of garden-variety slip-joint pliers from a hardware store and some rubber fuel-line tubing from an auto parts store. If you go this route, you’ll need two pieces of tubing, each about an inch long, of a size to slip securely over one jaw of the pliers. Grind the teeth off the concave serrated part of the jaws, leaving a smooth curve, and slip one rubber onto each jaw. Position them so that they cover the part of the jaws that you ground smooth; that’s the area in which you’ll grip a section. This is exactly the way Father Terry makes his section
pliers, and to be quite frank, I bought a pair from him rather than
expend the effort to make them.
Disassembly, Cleaning, and Sac Removal The first job is to get the old sac out. This means
taking the pen apart. Most pens have a section that is a slip
friction fit (just pushed into the barrel), but some (notably button
fillers, Touchdowns, and Snorkels) have a threaded section that
screws out. Virtually all lever fillers, except a few early
Sheaffers, are a slip fit. For simplicity, I’m going to
describe only the typical slip-fit lever filler in this article. (If
you decide you like this kind of work, get a copy of “Da
Book,” Frank Dubiel’s indispensable guide to fountain pen
repair, and let Frank show you how to handle the more esoteric pens.)
If it refuses to budge, it’s probably shellacked in place. (Sheaffer shellacked visulated sections but not hard rubber ones, for example.) You can resort to section pliers. Grasp the barrel firmly in your closed fist. (You can enhance your grip by using a rubber kitchen jar-lid gripper.) With the other hand, apply the section pliers to the section, and repeat the rocking/pulling action, twisting a little as if to unscrew the section. If it’s a slip-fitter, it’ll come loose unless it’s been shellacked in place, or possibly even glued (as on Waterman’s Taperite from the 1940s). In that case, you’re better off leaving it to a professional. Yes, I know, you just blew the price of a pen on tools. Use them on the next pen. With the section loosened, you should be able to work
it gently out of the barrel. Use your fingernails or a sharp kitchen
knife to scrape all remaining fragments of the sac from the end of
the section (the nipple). You need to get the nipple as clean as
possible so the new sac will adhere properly. You can use your knife
to scrape off the shellac that is probably there, and you can use
rubbing alcohol as a solvent for this operation. But don’t use
alcohol on a visulated section; the plastic used for visulated
sections is likely to be soluble in alcohol!
If the old sac died and dumped ink all over the inside of the pen, clean the barrel, too. You may also find that using your soaking solution on a barrel will make it easier to extract glued-in bits of sac. Get the barrel absolutely dry afterward; any moisture left inside can corrode the parts of the filling assembly. Sac Selection and Installation With everything clean, you’re finally ready to
install a new sac. If you don’t know the right size, try
different sizes (you bought the assortment, right?) until you find a
sac that just slips snugly into the barrel with the filler assembly
in place. Then choose a sac two numbers smaller; if a No. 18 fits
snugly, use a No. 16. You need to leave air space between the sac and
the barrel to keep the pen from transferring your body heat into the
sac when the pen is in your pocket. If the sac gets warm, the air in
it expands, and it can force ink out through the feed. This makes the
inside of the cap very messy, which is why you just cleaned it. No
matter what sac size you end up with, it needs to be a stretch fit
over the nipple. If you’ve chosen too small a sac, you may have
to go up one size. You can try stretching the end of the sac over the
nipple to verify that it’ll go.
Still clamping it, hold it up to the section, lining your thumbnail up with the step on the section that seats against the end of the barrel. Now mark the point on the sac that corresponds to the step between the nipple and the part of the section that fits into the barrel. This distance will be between 1/4” (6 mm) and 1/2” (13 mm). In the illustration here, you can see a bright line where light is reflecting off the step between the nipple and the rest of the section. Cut the sac at this point, being careful to cut straight across. If your pen requires a necked sac (with the open end
smaller than the diameter of the rest of the sac, like the neck of a
bottle), you must rely on the information in the Pen Sac catalog or
else measure the space into which the sac fits and then choose a sac
of the proper length. You don’t cut necked sacs; they have to
fit right. This may mean that you can’t order the exact sac you
need until you’ve taken the pen apart.
Once the sac is installed properly, put the assembly
down. Go away for half an hour to let the cement dry. It
doesn’t necessarily take half an hour, but if you adhere to a
firm half-hour waiting period, you’ll never proceed too soon.
Getting itchy and proceeding too soon means having a still-wet sac
come off in your hands or leak in the pen Now cover the new sac with a thin coat of talcum
powder (or graphite). This will make it slide into the barrel more
easily, and the filler will also work a little more smoothly.
Reinstall the section into the barrel, aligning the lever with the
nib as you go. (Some pens, mostly English brands such as Conway
Stewart, usually have their levers aligned on the underside, 180°
away from the nib surface.) There’s no need to cement a hard
rubber or ordinary plastic section in place unless it’s close
to falling out, but Sheaffer has always recommended that visulated
sections be shellacked in. If your section is so loose that it really
does fall out, try shimming it with a bit of paper.
Fountain Pen Hospital
Pendemonium
Father Terry Koch died in May 2004, and his tools are
now available from Victor Chen.
The Pen Sac Company
Wood Bin Ltd.
Widget Supply
KV Vet Supply
The information in this article is as accurate as possible, but you should not take it as absolutely authoritative. © 2003, 2004 Richard F. Binder |