Adjusting Flow On Ebonite Feeds

[ASCIIaardvark]

I got fpnibs.com's semi-flex nib, and love the softness & snap-back. It's a real delight on my Gama Sneaky. But it railroaded quite easily, even after heat setting.

 

http://i.imgur.com/8exsjPP.jpg

 

I deepened the ink channel and widened the gaps between the fins until the railroading stopped. But now it can bleed thru on Rhodia(!) and I sometimes see a meniscus in the ink I've just written.

 

So, for my next attempt at adjusting an ebonite feed for this nib, I was hoping for some pointers.

 

How do I prevent railroading? ...without making it so wet it nearly drips ink when I hold the pen vertically? (I presume the current feed can't be salvaged, but I have spares)

[Frank66]

Oh, the feed, the always overlooked, frequently ignored, most often forgotten topic compared with the nib which takes all the prize and attention.

 

First of all let me state that I have no experience with modifying ebonite feeds. My experience with PLASTIC feeds is never to widen the ink groove at the proximal third of the feed towards the nib tip; by this, I mean I try not to touch the part of the feed that corresponds to the nib slit and breather hole. I try to leave this feed part alone, especially the stop at the very end of the feed's ink groove towards the nib tip.

 

In the two thirds of the feed which is closer towards the ink reservoir / cartridge, I try to widen the ink groove with a 12C surgical blade or a very narrow pointed instrument. You must be very careful not to hurt your fingers when you try to do this. This can increase ink flow without the risk of ink over-flooding. It has worked for me in numerous occasions. Other people I have heard try to sand this same part of the feed with a couple of passes with a #600 sandpaper.

 

On the reverse side of the feed, only when I try to limit the ink flow, I use soft wax to narrow the air intake passage.

 

You can use soft orthodontic wax to correct your existing modified feed if you want to try to salvage it. Just try to narrow the widened ink grooves with soft wax. Also, make sure that you have a definite stop at the very end of your feed's ink groove.

 

Hope this might help some.

 

Frank66

Edited July 26, 2017 by Frank66

[lurcho]

Oh, the feed, the always overlooked, frequently ignored, most often forgotten topic compared with the nib which takes all the prize and attention.

 

First of all let me state that I have no experience with modifying ebonite feeds. My experience with PLASTIC feeds is never to widen the ink groove at the proximal third of the feed towards the nib tip; by this, I mean I try not to touch the part of the feed that corresponds to the nib slit and breather hole. I try to leave this feed part alone, especially the stop at the very end of the feed's ink groove towards the nib tip.

 

In the two thirds of the feed which is closer towards the ink reservoir / cartridge, I try to widen the ink groove with a 12C surgical blade or a very narrow pointed instrument. You must be very careful not to hurt your fingers when you try to do this. This can increase ink flow without the risk of ink over-flooding. It has worked for me in numerous occasions. Other people I have heard try to sand this same part of the feed with a couple of passes with a #600 sandpaper.

 

On the reverse side of the feed, only when I try to limit the ink flow, I use soft wax to narrow the air intake passage.

 

You can use soft orthodontic wax to correct your existing modified feed if you want to try to salvage it. Just try to narrow the widened ink grooves with soft wax. Also, make sure that you have a definite stop at the very end of your feed's ink groove.

 

Hope this might help some.

 

Frank66

 

Thank you. That is extremely interesting, and I'm going to try it tomorrow on some cheap feeds.

 

Can I ask you how exacly you widen the channel? I've found it very difficult to do anything other than deepen it.

Edited July 28, 2017 by lurcho

[Frank66]

 

Thank you. That is extremely interesting, and I'm going to try it tomorrow on some cheap feeds.

 

Can I ask you how exacly you widen the channel? I've found it very difficult to do anything other than deepen it.

 

I have only adjusted plastic feeds, and only when combined with elastic nibs or semi-flexible nibs that demanded more ink supply. If it is nail nibs involved, seldom does one need to mess with the feed in my experience.

 

With plastic feeds, I usually use a narrow pointed instrument and try to widen the top part of the ink groove. The bottom part of the ink groove stays unaltered so ink can travel there with capillary action. But it is only the top part of the ink groove that is widened slightly and only in the places of the feed that I described in my earlier post.

[lurcho]

Thanks for that.

[Ron Z]

There is a thread pinned at the top of the repair forum with a link to a site about fountain pen design. It is well worth reading the section on feed design. You'll understand better why one should be careful when modifying feeds. It is quite possible to exacerbate a flow issue if you do the wrong thing.

 

The set of a feed against the nib is often the cause of flow issues. I would suggest starting there, followed by removing of contamination from the feed. A good surfactant can often cure flow problems without modifying a feed.

 

I would not use a pointed object to modify a feed because you are likely to change the shape of the bottom of the ink channel, making it harder for the ink to flow. I would rather, use an extremely fine razor saw. I don't have a link to the manufacturer, but there are some out there that are only a few thousandths thick that fit into a #11 Xacto knife handle, which is what I use. They will cut a square channel, rather than a tapered one.

 

Many times the problem is not with ink flow out of the pen, but air flow back into the sac or converter. A minor change on the feed to allow more ink in (common on Schmidt feeds), can significantly improve the flow.

[lurcho]

Thank you, Ron. That is extremely helpful. I'll look out for that razor saw you mentioned, and I wasn't aware of a feed-design resource on this board. I was thinking about just such a thing.

[tmenyc]

Here's one made that is 0.1mm thick, by Tamiya for scale modelers, which I am in the increasingly rare moments when my bench is not covered in pens (the following is a paste in from the Amazon listing)

Tamiya TAM74094 Photo-Etched Craft Saw

 

If you have not used photoetched metal before, you need good pliers or a strong exacto blade to cut the pieces loose, and a strong sharp straight-edge to fold them over to fit in your exacto holder. And, those suckers are super-sharp, so use with extreme care to continue your work with ten attached fingers. They also come in .15mm and .2mm thicknesses.

 

Another good option is a surgical scalpel. I just lightly drag it through the feed slits, then use the USC to clean out what I've loosened. Amazing what it does for flow.

 

Tim

Edited August 1, 2017 by tmenyc

[lurcho]

Here's one made that is 0.1mm thick, by Tamiya for scale modelers, which I am in the increasingly rare moments when my bench is not covered in pens (the following is a paste in from the Amazon listing)

Tamiya TAM74094 Photo-Etched Craft Saw

 

If you have not used photoetched metal before, you need good pliers or a strong exacto blade to cut the pieces loose, and a strong sharp straight-edge to fold them over to fit in your exacto holder. And, those suckers are super-sharp, so use with extreme care to continue your work with ten attached fingers. They also come in .15mm and .2mm thicknesses.

 

Another good option is a surgical scalpel. I just lightly drag it through the feed slits, then use the USC to clean out what I've loosened. Amazing what it does for flow.

 

Tim

 

Hiya Tim. Thanks for the info.

 

Do you feel that you are cutting into the floor of the feed channels when you use the surgical blade, or that you are widening the gap?

[tmenyc]

Lurch --

The intent is not, maybe only rarely, to widen the gap. Unless it's a really crappy pen, I assume manufacturers put the gap they want in there for a reason and actually accomplish the gap they wanted to make. So, my intent, in lightly dragging the back end of the blade through the gap, is to loosen sub-visible accumulated dried ink. I go to some effort to not put any weight or force on the blade, just to let it do its job. If you have an ultrasonic cleaner, a trip through it after then slit cleaning operation usually completes the job. Most important is the north-south slit.

As for the rarely, cheap Chinese pens almost always come with uneven feed slit gaps, and often more than one is not completely cut. Those I endeavor to open with the blade size. Same with Indian feeds, although in truth less often now than more than five years ago.

 

Tim

[ASCIIaardvark]

Thanks all for your help.

 

I modified another feed, this time with saw instead of razor to widen/deepen the ink channel. And I left the lower-most part of that alone (where it starts scooping up toward the nib).

 

It's been very well-behaved for a while, no drips or that ominous "not quite drip" where I can see a pool of ink clinging to the feed & underside of nib waiting to splat if I'm too quick with the pen.

 

Upon closer examination of the first attempt at modifying the feed for this nib, I had cut the ink channel straight thru to the tip. The info on how feeds work helped me understand why that wasn't helpful.

 

Anyway: here's a pic of it working http://i.imgur.com/b7Yp0Kb.jpg

[Frank66]

Thanks all for your help.

 

I modified another feed, this time with saw instead of razor to widen/deepen the ink channel. And I left the lower-most part of that alone (where it starts scooping up toward the nib).

 

It's been very well-behaved for a while, no drips or that ominous "not quite drip" where I can see a pool of ink clinging to the feed & underside of nib waiting to splat if I'm too quick with the pen.

 

Upon closer examination of the first attempt at modifying the feed for this nib, I had cut the ink channel straight thru to the tip. The info on how feeds work helped me understand why that wasn't helpful.

 

Anyway: here's a pic of it working http://i.imgur.com/b7Yp0Kb.jpg

 

Your pen is looking great, writing sample superb too.

Personally I have only worked on plastic feeds and have used a #12C or a #15 or a #25 surgical blade to widen the ink slit, with extreme care so as not to hurt one's fingers. Or used a dental laboratory saw blade(0.3 mm) to widen and deepen and widen the ink channel or create a secondary channel next to the existing one. The latter one can easily borrow from any dentist or dental laboratory technician.

I always make sure that I cut a bevel at the end of the feed towards the ink reservoir, so that more ink can gather there to fill the ink channel.

A great how to picture is presented by [Opening Air Channels In Feed For Flex Nibs?: post #3] twomartoe found here: https://www.fountainpennetwork.com/forum/topic/309550-opening-air-channels-in-feed-for-flex-nibs/?do=findComment&comment=3762150

Figure deleted.

Edited August 16, 2017 by Frank66

[tmenyc]

I do hope that saw is for dental work done outside one's mouth...I'd be heading for the nearest door or window is that appeared during a visit. And I love my dentist!

 

Tim

[Frank66]

Surely intended for dental lab work outside the mouth, I love to keep both my patients and pens happy...

Edited August 16, 2017 by Frank66

[Pen Engineer]

May I add my five cents worth of thoughts?

I agree with Frank66 to leave the front end of the feed untouched where it engages with the nib. Another good point is leaving the other end alone where it connects with the tank, that's where often the breathing happens. They are the most critical sections of the feed.

As said before, scraping the ink canal with a fine blade cleans it. This operation also may deepen the canal thus increasing it's cross-section to allow more ink to flow. Scratching of the bottom of the canal increases its capillary pull, which helps accelerating the start-up time.

Once the ink flows, its maximum amount is controlled by the breather function at the end of the feed.

I would avoid widening of the canal to increase the ink flow. Since widening reduces the capillary force and the ink can’t be held, causing those drops behind the feed at the nib end. That’s why some feeds have fins there. Deepening has the same effect without this side effect.

I would not use surfactants because they alter the ink-feed relationship and they are very hard to get rid of.

In summary, I would rather try to achieve the goal by varying the brand of ink.