How to Replace a Pen Sac

It's tremendously satisfying to start with a pen that won't take ink and end with one that does. It’s always a good idea to learn by practice rather than waiting until a precious pen is on the line. To this end, I suggest you buy a couple of cheap pens on eBay or at your local flea market or antique mall to teach yourself the ropes before you turn your attention to your minty red ripple Waterman’s Ideal Nº 7 with the Blue nib. Arnold, Wearever, Epenco, and Tuckersharpe are some cheap names to look for, and there are countless no-name junkers that go for less than $10.00. (I use the term “junkers” loosely, as you already know if you've read Don Fluckinger’s Extra Fine Points series on these pens.) If you get pens that have sacs, you can easily rip ’em out. This, too, is part of learning to resac a pen.

Shown here, from top to bottom, are Nº 13, Nº 16 (latex and silicone), and Nº 22 straight sacs. At the bottom, for reference, are a Debutante Vacumatic diaphragm and a standard Waterman Ink-Vue sac.

Many pens — most, really — don’t call for the big guns, so you may not need section pliers immediately. When the time comes, you can buy the ones shown here very economically.

For sac removal tools, I use various implements such as hooks and dental picks and scalers. Shown below are a hook and two dental scalers. Hooks are ideal for grabbing sacs and dragging them out of barrels. To make a hook, form a loop on one end of a length of heavy-gauge coat hanger wire for hanging and to provide a “hold onto”; form the other end into a hook and fire harden it by heating it red with a butane torch and quenching it in cold water; and then grind the hook point into a flattened scraper shape trhat can slip between a sac fragment and a barrel wall. Scalers are particularly useful when it comes time to chisel pieces of petrified-in-place sac away from barrel walls and section nipples. You can get dental picks from a variety of online suppliers, and you can reshape the tips to suit your needs.

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.)

First, try using your fingers to rock the section gently back and forth sideways, pulling as you rock, to break it loose. Don’t rock too far or you risk cracking the barrel!

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 gripper square.) 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, enough persistence will make it come loose unless it’s been glued, as many cheap pens were done during World War II. 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 transparent section (or any other plastic section); the plastic used for these sections is likely to be soluble in alcohol!

This is your opportunity to do your pen a favor by giving it a thorough cleaning. Drop the section assembly into a bath of J.B.’s PERFECT PEN FLUSH or diluted clear household ammonia (not sudsy ammonia, and most definitely not the lemon-scented variety!) for five or ten minutes. Make an ammonia solution by mixing 1 tablespoon (15 cc) of ammonia with ²/₃ cup (158 cc) of water. After soaking the parts, scrupulously clean off any ink residue and the cleaning solution. This means flushing water through the system, which you can do by using an ear syringe to force water through the section from the sac end. (If you don’t have an ear syringe, you can use your mouth for this job.) When the assembly is clean, dry it thoroughly; blow some air through to dry the inside.

Clean the cap the same way, paying particular attention to getting the ink out from inside the cap. One way to do this is to use a paper towel. Twist one corner of the towel into a long thin spear (sometimes called a twizzle), and insert it into the cap with a screwing motion. Turn in the direction that will keep the twist tight. Drive the twizzle as far down as you can get it. Repeat as necessary.

Now, if the sac didn’t come out in one piece, extract its remains from the barrel. Long thin alligator forceps can be helpful here but aren’t a necessity. If the sac is ossified, you can probably just dump out the chips. Occasionally you’ll run into a sac that has managed to glue itself, whole or in pieces, to the inside of the barrel. This can get ugly. Take your time; as with the nipple, you want to get the barrel clean. Be careful not to damage the filler assembly.

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.

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 that's a little smaller. For larger pens, go down two sizes; if a Nº 18 fits snugly, use a Nº 16. For smaller pens, you can usually go down one size (e.g., from Nº 14 to Nº 13). 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.

The sac needs to be the right length. Most sacs are “straight” sacs; that is, the diameter of the sac is the same along its entire length. Sacs are made extra long; in most cases you will need to cut your new sac to the right length. (Very large pens such as a Waterman 58 are long enough that you can sometimes use the sac uncut.) To find how long it should be, slide it into the barrel, closed end first, until it hits bottom. Slide it back out about 1/8" (3 mm) so that it won’t butt against the end of the space into which it fits. Clamp it with your thumbnail right where it enters the barrel, and pull it out.

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.

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.

With the sac ready to install, apply a small amount of sac cement (shellac) around the outside of the nipple. Be careful not to let the cement get into the inside; it’ll clog the feed — possibly permanently! Spread the open end of the sac, stretch it over the nipple, and adjust it so that it’s pushed all the way down and is seated against the step. If you find that you’re a little clumsy and have trouble fitting the sac in place, you can buy a sac spreader. Pendemonium offers these little gems for $5.00. I recommend that you buy yours yesterday, as today — with wet cement drying on your pen — isn’t the best time to go shopping. The sac should stand straight up, in line with the section, and the stretched part should be symmetrical on all sides. (The sac shouldn’t be pulled over toward one side of the nipple.) If you like, you can run a very small bead of cement around for an improved seal right where the sac butts against the step.

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 or — worst of all — glue itself inside the barrel.

Now cover the new sac with a thin coat of talcum powder (or graphite). This will make it slide into the barrel more easily. The sac will also repel moisture, and the filler will 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.

Et le voilà! You’ve just accomplished a task that used to require the services of a highly paid professional. You’re on the road to restoring your way to a better pen collection. Fill your revitalized pen and enjoy the ride!

Notes:

We use section pliers daily, often two pairs together, and we’ve settled on what we think are the best. The pliers shown here are actually intended by their manufacturer for use in the automobile industry. Don’t be lured into buying cheap lookalike pliers, though; I’ve used several brands of lookalikes, and they don’t work alike. These pliers are so good that we offer them for sale.
We offer a kit containing scrapers, hooks, and tweezers.
Sacs are available from several online sources, including RichardsPens.com. For sacs that we don’t stock, I recommend the Pen Sac Company for latex sacs; for silicone sacs I go to Wood Bin Ltd. The Pen Sac Company sells a bewildering variety of straight sacs, necked sacs, tapered sacs, Ink-Vue sacs, and Vacumatic diaphragms. 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.) Silicone sacs from Wood Bin are sometimes a better choice than latex because silicone doesn’t outgas sulfur vapor that can cause some celluloids to turn brown. It’s also transparent, a nice feature for demonstrator pens.
Some pen suppliers can sell you sac cement; most offer small bottles with an applicator brush for about $5.00. We offer a specially selected sac cement.
Do not use baby powder or ladies’ dusting powder, or any powder that contains fragrances, cornstarch, zinc oxide, or other additives! These products are oiled to protect delicate skin, and oil eats rubber. Pen sacs are rubber… If there’s no plain talcum powder in the house, buy some. (I should point out that pure talcum powder is not easy to find these days. Your best bet might be a billiards supplier, but one enterprising collector wrote to tell me that he had obtained a lifetime supply by slitting open an old bicycle inner tube!) If you absolutely cannot find talcum powder, you can substitute powdered graphite. This stuff is sold by hordware stores and locksmiths for lubricating locks and other mechanisms that are exposed to cold and wet. It's messy, but it does work.
J.B.’s PERFECT PEN FLUSH is a special formulation of surfactants and cleaning agents. We don’t make it, but we’ve been using it for several years, and we think it works very well.

The information in this article is as accurate as possible, but you should not take it as absolutely authoritative. If you have additions or corrections to this page, please consider sharing them with us to improve the accuracy of our information.