In order to clean a feed (Waterman Phileas in my case), several users suggested 10% of household ammonia in water works best. But, please, can someone clarify 10% - is it concentration, molarity, or 10% by volume ?

Brand new Phileas from a store, a medium nib has a trouble with ink flow. Often a whole letter is missing from a word. Tried Waterman blue ink that comes in a box with the pen, also tried Pelikan black ink, tried different papers with both inks - it did not help.

I am afraid someone bought the pen, changed the nib section with a defective one, and returned the pen to the store with the defective nib. I see no other explanation. The pen is new, in a box, from a regular office supply store. The bad part is, I can not return the pen because I got it on a big sale at the end of December 2007, no returns.

I have no idea what the problem is, but I noticed the skipping is not that bad when I increase a nib pressure to the paper. About the same pressure as when writing with a pencil. However, it is not the way the FP should be used. If the trouble is the nib and not the feed, please someone tell how to adjust a split between tines.

Thank you.

Honestly, I don't think the exact concentration is all that important, within reason. I use a splash in a cup. Something in the range of a tablespoon or two per cup of water. (So, that would be by volume.)

10:1 by volume.

10% by calibrated slurp. 1 slurp ammonia : 9 slurps water.

I wouldn't be fussed about exact proportions, all you are trying to do is to dilute the ammonia to a level that is convenient and safe to use, but still effective. Don't forget, you are talking about ammonia you buy in your local grocery, not AR grade.

It sounds to me like you may have a baby-bottom problem, if not the feed.

What exactly is a "baby bottom problem"? I've never figured that one out....

Hold your pen up nib towards you, use a loupe and see how the slit looks, if the writing surface looks anything at all like a “3” (turned 90 degrees clockwise) you have “baby bottom.” In other words the material on both sides of the slit are not in contact directly with the paper. In this case you need to carefully remove material until the slit comes into contact with the paper, then polish for smoothness. (And without recreating the baby bottom problem again.)

This is exactly what I thought when reading this too- especially with the note that pressure seems to fix the problem.

I doubt its the feed on a new Phileas. Could be a troublesome nib - baby-bottomed, which would require reshaping or "tuning" the nib, or it could just need the gap adjusted. Check the Pen Repair FAQ, any of the "Flow Problems" links right at the top of the page should give you some helpful pointers.

It could be the feed. Granted it's unlikely, but it could be. Case in point: I bought a Liaison at DC. Nice pen, but I see why they were selling it - the pen would quit writing rather quickly. Tracing the slit in the feed with a piece of brass shim stock I knocked out a long piece of plastic from the slit. Once out, the problem was gone.