*** We only officially accept Eureka ultem ink cartridge as main ink storage device for our pens.
We no longer officially recognize Con-70 / Con-40 as converter for Eureka fountain pen models.
Although they are still compatible, you must read con-70 related manuals / tips before using them.
It is tricky to get it right, although if you are skilled / experienced with the system, it should be fine.
For those having difficulties getting it to work properly, we recommend the machined ultem cartridge instead.
also, because of the way Con-70 was produced, external surface is not consistently accurate between batches / not perfectly round.
So some of them may require "taming" by wearing the external surface down to match eureka grip part.
This is only problematic for fitting into eureka grip section, which uses external surface to seal (as opposed to internal surface).
1. when installing / removing, give a bit of rotation
2. (below picture) if ink is on the outside wall of Con-70, wipe it clean, then install.
otherwise, the ink will be pushed out and contaminate thread area (This is not leaking)
similarly, inside wall of grip section must be clean as well.
3. if there's a real leakage, then all converter ink will be leaked out from the nib area within minutes.
so please evaluate your situation correctly.
4. If you want zero contamination, do not remove the con-70.
just keep in in there. frequent installation / removal will lead to contamination, unless you clean all sealing surfaces (converter outer wall & grip inside wall)
5. if you give it a spin while installing / removing the converter, then the parting line (seen in the 3rd picture) will disappear eventually.
6. This was designed intentionally, to achieve maximum durability for grip, feed, etc.
so any design change is not possible.
This design allows wall thickness of all related parts by almost 2 times, so very good durability.
*** 7. If all efforts fail for some unknown reason, as a final resort,
put some silicone grease at Con-70's sealing area (Con-70's outside wall @ frontal area).
Only small amount is needed.
Use the pen without removing the converter. just keep it in there, unless it is required.
this will seal the converter 100%, in all cases.
*all newer pens have additional O-ring installed onto the tail of the ebonite feeder.
O-ring is not absolutely necessary, but if you want secondary protection O-ring can be purchased @ "Shop(Parts)" category. the O-ring can be added to all 5th gen ebonite feeder products.