I would like to continue an interesting discussion we started up in FPN -but couldn't conclude- about whether MB piston fillers should be kept with water when they are not in use to prevent cork shrinkage or not.
Just to recap, while sole people follow this practice, some consider that it is not advisable to keep pens filled with water -even distilled water- during prolonged periods because this can cause damage to some undetermined parts of the pen. Besides, there are those who have reported having MB piston fillers empty during as long as one year without any cork shrinkage and that as long as the cork is conveniently treated with silicon grease there should not be any problem.
The fact is that I've found that ALL my seven MB piston fillers have experienced cork shrinkage after a few weeks out of rotation, so that the pens either would not take ink at all or take ink but rapidly loose it as a result of the pressure exerted by the air contained in the chamber beyond the cork piston.
I've managed to re-hydrate the corks by keeping some distilled water inside the pens for a couple of days and now they behave ok.
The questions that keep open are:
- Is there evidence that keeping an old piston filler filled with distilled water causes damage to the pen or is it just a non-tested assumption?
- Does the problem of cork shrinkage stem from the fact that those corks might need to be replaced or treated with silicon grease and so the solution to the problem described above is pen maintenance rather than using such recipes as keeping the pens filled with water?
- Could the problem be connected with the particular humidity condition in some locations, so that perhaps I have experienced the problem because my pens have been storaged under the extremely dry air of Madrid?
- Is it ok to keep the pens filled with water under these circumstances?
- Or in the contrary, is it preferable to avoid risks by keeping the pens empty and if they experience cork shrinkage to try re-hydratation just before putting them back in rotation as I have done these days?