I bought my Vac700 in late March 2015 (i.e. just over a year ago) and it has seen moderate use. The large ink capacity makes it ideally-suited for use at conferences or on longer trips, and I enjoy writing with it. The pen has probably been fully inked-up and subsequently cleaned out about half-a-dozen times, perhaps as many as ten times since I got it.
There is now a specific problem with the pen, and I have a few questions for you:
1) Have you experienced a similar problem?
2) Is my diagnosis correct (could there be something else causing it, and if so, what?)
3) Any suggestions on how best to proceed?
Here's my problem:
When I last tried to fill the pen, it would not fill - it somehow failed to make the necessary vacuum, and couldn't get more than a dribble of ink into the barrel.
I disassembled the pen for the first time, made sure everything was properly clean and lubricated and properly reassembled. Of course, the problem persisted.
So I took it apart again and looked at everything under a loupe. I discovered that there are actually two O-Rings on the end of the barrel (the part that screws in). The larger O-Ring is the more obvious, and the smaller O-Ring is easier to overlook.
The problem seems to be with the smaller O-Ring. It actually seems a little flimsy, and it has become a little 'floppy' or stretched over time. That is, it no longer makes the necessary tight fit with the thread. See picture.
(Image: end-of-barrel unit, with O-Rings highlighted)
I was surprised to see this part failing so quickly, particularly if it is crucial for the pen's operation. I don't know why a problem with that O-Ring should cause the vacuum to fail - the larger O-Ring is fine, and should be sufficient by itself. But in the absence of any other obvious cause, I'm assuming that the perished smaller O-Ring is indeed the problem. I am therefore looking to replace it.
It's only a small part, and I can probably find it cheaply at my local DIY/hardware store, but that's a hassle (the store is not all that local). Also, I'm wondering whether this is a potential issue for others, and whether I should approach the company I bought my pen from.
Any thoughts in response to my questions? Have I missed something? Thanks!