The ink somehow changes over time in the rapidograph cartridges...ammonia doesn't dissolve it. My first pens were the refillable isographs....I switched to the rapidograph...and yes, the cartridges are handy....but I'm going back to the refillable isographs.
The ink somehow changes over time in the rapidograph cartridges...ammonia doesn't dissolve it. My first pens were the refillable isographs....I switched to the rapidograph...and yes, the cartridges are handy....but I'm going back to the refillable isographs.