View Full Version : Cork or O-Ring

February 20th, 2015, 03:10 AM
What is the community view on replacing a leaky cork piston seal on a Pelikan 100N with a nitrile O-Ring or plastic seal? This is going to happen to me sooner or later, in fact most probably sooner rather than later as I have a pen with a problem.

Is substituting a cork seal frowned upon or is it considered sensible?

Strange, however I would have never worried about things like this prior to joining fpg.......

February 20th, 2015, 05:11 AM
You might be interested in my piece about repairing an Osmia 884 (http://fpgeeks.com/forum/showthread.php/7911-Osmia-884-The-Five-Minute-Solution!) with O rings.

I say that life's too short for messing about with corks!


February 20th, 2015, 05:30 AM
Buckle up as this thread is probably about to get interesting. I don't know that there is a "right" answer but there are a plethora of opinions.

Personally, I prefer to use cork with pens that originally had cork seals but I have also used O-rings.
The key to both is proper sizing.
Either way both will work perfectly if done correctly.
Both can fail to seal, or even worse split the barrel, if done incorrectly.

Cork was not originally used because it was better but because technology had not caught up with rubbers to the point where it was economical to use rubber or synthetic rubber. It took a war to make the transition to O-rings possible and practical.

I have never even considered having a cork seal made to replace a synthetic seal. That statement alone probably holds the key to THE answer. So really it comes down to if you want to be a purist or not.


As a side note, I would have more pens restored with O-rings if it were not so expensive to get custom sized O-rings. The last time (early 2014) that I talked to Parker Hannifin about custom O-rings I would need to make a minimum buy on the order of 10,000 units to get them to even consider it. There is no way that I could come out ahead doing that. I could send more pens that I will ever own to get custom corks made for far less money.

I have been through 2 sets of custom made cork tools (plus the cheap Chinese cork borers) and have yet to find anything that really works well for making my own cork seals. The cork that I was using was probably the biggest problem, now in hindsight, but that is where I am. I do intend to make a third try at some more custom cork tools as soon as I decide exactly what I want.