|Filling Instructions: Plunger-Fillers|
Plunger-fillers can be recognized by their thin, rodlike plunger shafts, made of either stainless steel or carbon steel with a glossy black hard rubber coating. If the shaft is thicker than 2mm or so, it is likely that the pen is a pump-filler or pneumatic-filler instead. Note that some eyedropper-fillers are equipped with ink shutoff valves that make them closely resemble plunger-fillers. Most of these pens are Japanese, and modeled on the British Onoto.
To fill a plunger-filler, unscrew the end knob and gently pull on it to extend the plunger shaft. Immerse the nib, then depress the plunger in one smooth, swift motion. Screw the knob back into place, and you are done.
If there is liquid in the barrel, forcibly pulling out the shaft (as is often done by those who mistakenly believe the pen fills on the upstroke) puts great stress upon the packing unit, which may lead to leakage along the shaft. A gentle touch on the upstroke will do much to prolong the interval between overhauls. Another precaution that will keep a plunger-filler working smoothly is the occasional lubrication of the plunger shaft with silicone grease (available at dive shops -- note that this must be 100% pure silicone, with no petroleum-based ingredients). If you have a plunger-filler that needs repair, make certain that the repairman is not using rubber plugs jammed inside the barrel. The only proper method is to open and repack the original packing unit. Plugs are a popular stopgap, but can do serious damage to a pen over time and are prone to early failure. For more on plunger-filler repair, click here.