My Kaco EDGE is drying out, even when using it the next day. I feel that the issue is related to the converter, because usually I can fix the issue (even for a couple of days) by driving the converter just a little bit outwards and then cleaning the pen. The converter is a rather cheap one made of plastic. It came in a set with the pen and the schmidt EF nib. I saw this set of many places, but it looked like this:
I've not known a converter causing issues such as drying out. I'm a bit confused about how you are fixing it? Do you mean you screw the converter a little to lower the piston and that gets it going again? That is a common fix for a dried up pen.
Have you tried different inks? It might be the ink is just not compatible with the pen.
As already mentioned you can get converters (Faber Castell makes one) with agitators in them to help prevent the ink from staying at the wrong end of the converter but most of the converters I own are fine without them.
I would try getting a sample of a well known reliable ink such as Waterman Serenity Blue and seeing if the pen behaves well using it. Also try flushing your pen with some mild soapy water or pen flush, maybe even allowing it to soak for a few hours. You may have dried up ink or some oils from manufacturing in the feed that are impeding flow.
Sometimes it is just a problem with the pen/cap design due to a poor seal. I had a wooden Conklin All American Golden Walnut and it would stop writing if left for more than a few hours. The cap had no liner in it and the raw wood just sucked all the moisture from the nib and dried it out. Ultimately despite liking the pen I just sold it due to frustration.
Do you mean you screw the converter a little to lower the piston and that gets it going again?
Yes, that's what I am doing. I had no trouble with the cartridge I used before, so I could try that again to identify the converter as the issue. The ink is Parker Quink Black (but two decades old, so possibly alcohol-based? I read something about a change in formula). It is supposed to be one of the more reliable ones.
If I don't have problem with a cartridge, then I can exclude the cap as the source of the problem, right?
If a cartridge behaves fine then the cap seal is less likely to be the problem, but again different inks behave in different way that may accentuate a cap seal problem. Very few pen caps create perfect seal anyway but some are better than others (I think Platinum have the Slip and Seal system).
If your ink is alcohol-based (never heard of this but then I don't have any old ink) then I would imagine it would be highly susceptible to evaporation and drying out. I'd pick up some different water-based ink if you prefer the CC over cartridges.
As a follow up to warped, do you have the old cartridge and a blunt syringe? I can't tell if you tested with an unused or refilled cartridge. I will run with the assumption you only tested with an unused one. You can test if this is an ink compability or an evaporation issue by filling the old cartridge with the Quink. No need to fill it completely and waste ink. 1/4 should be enough to tell. Use the pen as you did with the converter and see if you have the same evaporation issues. If it's also evaporating, it is either a cap seal issue or a pen and ink combo. I second Warped's recommendation to try the ever reliable Waterman Serenity Blue (the "standard" blue shade") ink. That will give you a good idea if your pen has an evaporation issue (still drying out quickly) or a pen/ink combo issue. If there is no evaporation (no dry out and ink isn't getting darker), then you can start branching out to different inks to figure out what works with the pen. If you do not have any issue with the refilled with Quink cartridge, then I think that might suggest a converter related issue. The agitator might help. A new converter might help too. This scenario is a bit harder to diagnose to be honest.
If I was a gambler, I would bet it's either an evaporation or pen/ink combo issue.
photos in the Amazon link show the converter doesn't have any springs or balls inside the ink chamber. Is that accurate? Other converters I've used have springs or balls that help break up surface tension, especially because it's a low capacity chamber.
do you clean/flush your pen regularly? Over time, some ink can dry up in your feed and worsen the inkflow.
The Amazon link shows the international standard Schmidt converter, they do not have anything inside. I have those in several pens and they never cause issues.
My Kaco EDGE did the same thing - not sure why. Also had issues with hard starts. I didn't put a lot of work into it and eventually gave up. Instead, I got a Jinhao 80 and swapped in a Lamy 1.1 stub that I had laying around, and it's been excellent. If you can't get the Kaco to write well but want something in a Lamy-2000-lookalike style, might consider the Jinhao 80. I have a couple of them now and they are great!
Thanks for the helpful comments, I will try your suggestions out (I am traveling atm so my inks are not readily available)! A stupid little thing I've just tried is to fill the cap with water ... and it leaks quite a bit, where the fancy "edge" is situated. So that might be the issue