Since it arrived, only five days ago, I have been hugely pleased with this pen. It continues to behave well and to write beautifully. All indications are that we will be well suited to each other. Just a few items to report, by way of update:-
Having established that this eyedropper pen showed no signs of blobbing ink whilst only a third full, I topped it up to test whether that would invite any trouble. Still there has been no blobbing, despite the added pressure of a full tank of ink. The feed does a good job of holding back the tide.
I took another look at the other two nibs, the extra fine and the medium included in the set. I had been reluctant to take out the lovely oblique broad nib in case of spoiling the magic, but it is simple enough to unscrew one nib unit and insert another. I tried the extra fine first. Once the ink had made its way down, it was still a very fine line and the nib was firm too. It may have its uses but in terms of enjoyment it fell far short of oblique broad. I have flossed it with brass shims to ease the gap between the tines a little.
The medium nib was somewhat better. I found that it wrote reasonably well in my occasional lefty-underwriter mode, but for overwriting it was not very pleasant. Having confirmed this, I was pleased to get back to using the oblique broad.
The nib units can be disassembled. The nib and feed are friction fit in the housing and can be pulled out if necessary. However they will only go back in one way, so my suggestion of rotating them in the housing to offset the nib in relation to the roll stop jewel on the barrel, is not possible.
Luckily with the oblique broad fitted, the multi-faceted jewel roll stop was well out of the way of my grip. However, I still decided to file it down a little, so that my fingers would not keep finding it. The jewel is not particularly effective as a roll stop anyway and it is much safer to put the pen down on a pen rest so that it will not go anywhere.
I use the pen with the cap posted as this is the most comfortable. There is no metal on the cap at all – it is a piece of clear acrylic. The absence of a cap band to give it some strength does worry me slightly and I fear that it could crack if forced onto the barrel. I will be careful not to overdo it when posting but a little shove and a twist is enough to fix it on securely.
All in all I remain delighted with the pen and especially its oblique nib, even though the other two nibs are rather surplus to my requirements.
Fountain pen blog 
Hello,
First of all, thanks for the blog, that I read with pleasure. One of the things I like about your blog is that you seem less subject to hype than most bloggers, who always seem to review the latest novelty, and we see the same brands everywhere: Leonardo, Esterbrook, these days Otto Hutt and Tibaldi. Whoever is sending pens for review. But here, we read about a Cross or a Waterman actually bought in a store. Those are excellent pens, ignored by most bloggers because they are not supposed to be cool these days.
Just one remark on this post about the Moonman S5. Eyedropper pens are most prone to blobbing when they are almost empty, not full. It is not the weight of the ink that makes them blob, it is the dilatation of the air in the ink chamber when you hand heats the pen. The more air there is in the chamber, the more its volume increases when the temperature rises, and expels the ink through the nib.
Thanks again for your blog, and for the review of this Moonman.
Mikel
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Thank you very much for your kind comments on the blog.
Also I am grateful the explanation about the causes of ink blobbing in eyedropper pens. This one does have a large capacity and it could become a problem once this is mostly filled with air, in a warm hand. I shall proceed with caution. I have been lucky so far but perhaps I had not yet reached critical low ink volume or warm enough internal air temperatures. If it does suffer from blobbing then keeping it filled may be the answer.
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What cartridge do I use for this pen?
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This pen does not use cartridges. You unscrew the barrel and put ink directly into the barrel. You need to use a pipette for this to lift ink from a bottle and release it into the barrel. It is therefore called an eyedropper pen. An eyedropper device is included in the set. It is great fun and it holds a ton of ink!
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This is a ggreat post thanks
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Thank you! Now, some months since writing this post, I remain very happy with this pen, and particularly the Oblique broad nib.
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