I recently purchased 3 Ackerman pens, 2 fountain and 1 pump.
https://ackermanpens.com/
https://youtu.be/_vT4PFPnDvk
I had heard of fitting a dip pen nib to fountain pens before, but never tried it due to fountain pens requiring fountain pen ink and my mistaken belief that all of said category of ink was not waterproof. So when I saw the Ackerman pens with their ability to use dip pen nibs out of the box and the ability to use india ink and other waterproof drawing inks, I was excited. I had read some discouraging things about Ackerman pens, like they were leaky and dripped when pumped, but this was for older generations of the pens (I believe the current is the 12th) and I also heard good things from others. I had also heard although a very nice guy and willing to help, his customer service could be hit or miss, since this was more of a hobby for him and he had a day job. But I took the risk anyways.
The pens themselves are made of black acetal resin (Delrin), which is well machined, with a smooth, satin finish, probably created with just a finish pass on the lathe. The finish feels good in the hand and is quite grippy, despite the low surface roughness/texture and the fact that Delrin tends to be slippery. The cap and barrel threads are smooth and tight with no slop. The cap has a stainless steel clip that is stiff and springy. The feed is also of Delrin and has a fitted cut out for the nib. It fits tightly and firmly into the section without requiring excessive force to install or remove. Removing the barrel reveals an open eyedropper filled "cartridge" ink reservoir, which fits tightly into the section. The pen can also be converted easily to an eyedropper using the barrel itself as an ink reservoir, because of the tightness of the barrel threads, silicone grease or other sealant is not needed (I tested this). The cap posts tightly and securely on the end of the barrel. The overall design is minimalist and utilitarian, without decoration, reflecting its intended use as an artist's tool, but I don't find the pen to be ugly but rather classy with its satin finish and lack of flashy additions. It is quite light weight, but still feels solid and robust because of the construction and material. Overall the pen doesn't feel cheap at all, despite its plastic construction, but rather very well made. I have heard some have had problems with leakage from the feed/nib into the cap during transport, but cannot speak to one way or the other since I have not carried this pen. It hasn't leaked during storage, even when left horizontal.
When I got the pens, I immediately set about testing them and was disappointed. Initially, they had problems with hard starting and inconsistent feeding, sometimes I could get a nice amount (about 1/2 of a dip pen) and length of flex, other times they would railroad with just a bit of flex. I cleaned the pens thoroughly, initially I had only cleaned the nibs, and the hard starting and inconsistency disappeared. But I still wasn't happy with the amount of flex. I emailed Mr. Ackerman about it but he didn't respond, so I decided to hack the feeds to see if I could increase the flow. Well I only ended up ruining the feeds, the ink flow was worse, hard starting and inconsistent ink flow returned and with more modification I ended up with blobbing and gushing. I don't think the material of the feed, Delrin (acetal resin) lends itself to modification. Still with no reply, I was frustrated and boxed up the pens to send back (he has a 30 day no questions asked return policy). Then he responded with a few suggestions and I responded that I had ruined the feeds trying to increase the ink flow, so he sent out some replacement feeds in various designs for me to try (which I am still waiting on).
With a level head, I looked at the results again, and realized my expectations were far to high and that the pens had actually functioned incredibly well. I was looking at them from the perspective of compared to a dip pen and expected them to match that level of performance, which frankly after actually researching a little into fountain pens (in an effort to increase the ink flow) is unlikely and probably impossible. Had I instead compared them to the performance of a fountain pen, I would have realized they matched or exceeded the performance of a vintage wet noodle, a modern flex pen modified for more flex, or a modern pen modified to use a dip pen nib. All this while using a waterproof drawing ink that would have clogged a fountain pen almost immediately, with the standard feed (turns out Mr. Ackerman currently makes two different feeds, a standard for fountain pen ink and a high flow for india/drawing ink), with a consistent ink flow and without clogging.
So in short, vintage wet noodle performance using india ink with the wrong feed without clogging. Once I receive the new feeds I will do a more formal and in depth review.
As an FYI, the pens are made mostly from Delrin (acetal resin). Although Delrin is impervious to many common chemicals, it is attacked by ammonia and chlorine, so do not use any pen cleaner containing ammonia on these pens. A good cleaner to use would be Koh-I-Noor Rapido-eze.
