(Long read for the handful of people who like fixing pens haha) tdlr; old gasket, big burp, new gaskets, tiny burps

i love safeties, they are comically big and fun to use (if anyone has a waterman 20S pls lemme see it!), but they take quite a bit more work to diagnose and fix up compared to the simple eyedropper and lever filler, or for that matter plunger fillers.

my 48 was burping suspiciously, and not in a regular cadenced way like safeties usually do when writing for a long time. And since it’s a big pen, it’s a lot of ink lol.

First, i started to triage as there’s only two potential air gaps in the vacuum environment within the pen:

1. Nib Feed Assembly 
2. Rear Gasket Assembly (or “packing housing”)

After heat setting and re-shaping the nib feed assembly to near perfect tolerance to match the front end of the barrel, I tested using a simple science class trick.

While holding the nib feed assembly flush against the front of the barrel, i filled the barrel with water and then sealed the back of the barrel with my thumb. This creates a vacuum effect within the barrel and if the tolerances are right, no water will escape from the barrel. It passed this test perfectly.

But when I installed the rear gasket assembly, it was leaking out the front slowly but surely.

So I took apart the rear gasket assembly and hand cut some o-rings from a silicone sheet and lubed with silicone grease. Don’t do this for long term repair! Silicone x silicone is bad idea, but i didnt want to make a 20mins trip to the hardware store until i knew what was wrong. 

With the new gaskets, the burping subsided for the most part, but it was very low tolerance with my hand cut gasket kit so with machined gaskets it will create an even better vacuum seal.

Waterman inks have very low surface tension which also doesnt help lol. 

(restoration tips) safety fountain pens