Is there such a thing as a refillable porous point pen?

Question

I'm wondering if there's such a thing as a refillable porous point pen. To clarify:

• By refillable, I mean from bulk ink, like a fountain pen, not where you reuse the pen body and replace both the ink and delivery system like a pen refill. My searches have turned up only fountain pens and technical pens (metal capillary tube ink delivery), as ones where you refill just the ink.
• Porous point refers to a hard, rigid porous point, not a soft tip like a felt marker. I've seen refillable brush pens, but those don't have a rigid tip.
• Pen refers to something that draws a line with a width in the ballpark of a ball-tipped writing instrument, like a ballpoint or rollerball. A micro-fine tip would be great, like the Micron 0.1 mm and smaller technical/art pens, but those tips are lucky to survive using up the original ink. So I assume anything refillable would need to be in a size range at least like the Pilot Razor Point (0.3 mm), that's designed to hold up to normal writing, and produces a line like a fine to medium point pen.

Most porous point pens can be recharged if you pry off the back cap, but they aren't designed to be refilled. If you inject too much ink, you can get a leaky mess. Something designed for refilling will have easy access and a controlled amount of ink.

If anyone has used such pens, it would be a bonus to know whether the tip survives extended use through refilling, and retains a point of about the original size, or does it wear down, producing an ever-widening line?

I haven't seen ink sold for the purpose of refilling such pens. My assumption is that the ink viscosity would be similar to fountain pen ink, and the precise viscosity probably isn't critical. If somebody is aware of a characteristic of porous point ink that is different, making fountain pen ink unsuitable, that would also pretty much answer the question.

Answer 1

I'll close the loop on this question. Thanks to @ChrisH for identifying "fineliner" as the useful search term.

Refillable fineliners do exist, and there are a few products currently available. Both water-based and oil-based inks are used for this type of pen, so fountain pen ink probably wouldn't be precluded for refilling if the pen started out with water-based ink.

Copic makes a pen with not only refillable ink, but replaceable nibs, and ChrisH identified a double-sided pen from Zebra with different size nibs at each end.

The currently available products that showed up in a search all require unique ink cartridges. A manufacturer of generic cartidges could duplicate them, but it appears to be such a small niche market that there wouldn't be a payback for the effort.

The cartridge approach is fast and clean, with reduced risk of needing to remove ink stains from yourself and other things. But with no generic cartridges to hold down market prices, the refill ink can be more expensive than disposable fineliners.

It generally isn't a good idea to try to refill the cartridges because removing and replacing them stretches the hole and they can leak.

Bottom line: such products do currently exist. But the business model seems focused on selling over-priced supplies rather than supporting an enduring masterpiece of writing perfection. The refillable pens don't provide obvious benefits in use over less-expensive disposable pens, but probably contribute a small reduction in waste plastic.