# Jowo Nib unit leaking



## DutchPlatypus

I made a couple of kit-less pens in slightly different shapes using Jowo nib units. I’ve been testing these pens and since I only had one XF nib unit, I switched the section from one cap and barrel set to another. In doing so, I noticed that the nib unit is more prone to leaking in one pen than in the other. So I’m puzzled about what may be causing this. 

For the barrels, I made the bores for the converter the same. The bore in one cap is slightly bigger than in the other because I used different cap threads, 1/2-20 in one and triple lead M13x.08 in the other. I do notice a difference in the tightness of those threads. The M13 threads are quite a bit tighter than the 1/2-20. It is the M13 pen that sees more leakage than the 1/2-20. Sooo, does anyone have any idea what may be causing this? Could the tighter threads be building up pressure somehow? Can the shapes of the insides of the pen affect leaking of the nib unit?

Thx for any input you can give,
Edwin


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## Curly

Grabbing at straws but it will subscribe me to the thread. 

I think the tight threads could act like a piston when you put it on and compress the air in the cap side that would dissipate after a little while. Not sure if that would cause the leak. In the same way the tight threads will create some suction when unscrewed and possibly draw out some ink. I'm just guessing.


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## DutchPlatypus

Hi Curly, thanks for sharing your straws. The suction part is an interesting thought that hadn’t occurred to me yet. I could try to cut the barrel threads a bit more by tightening the screws holding the die in the die holder. The die has a slit which I guess is made to adjust the thread dimensions (?). Perhaps someone knowledgeable can enlighten me here [emoji57]


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## duncsuss

Bottom line first: it should not leak, period. "More prone to leaking in one than the other" suggests it leaks in both, just not as much in one of them -- it shouldn't, at all.

The first thing to check is that you have fully seated the converter on the nipple of the housing into which the nib and feed are pushed.

I always check this while making the section, because if you don't get that right there's every chance there will be leakage inside the body of the pen.

Take the housing/nib/feed out of the section, push a converter on it all the way, and set your calipers to total distance from tip to tail of this combination. Then remove the converter, screw the housing/nib/feed into the section, push the converter on there again, and check that it still fits between the jaws of the calipers. If it doesn't fit, you didn't push the converter in as far this time as when there was no section in the equation. Maybe your tenon is too long, or the hole for the converter is too tight, or there is too much empty space at the back of the housing (maybe you didn't drill and tap far enough into the section, for example).

If your measurements are correct and you still get leaking into the barrel of the pen, the mouth of the converter is too wide, get one that fits nice and tight.


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## bmachin

+1 to what Duncan says, but before you go even that far, remove the nib,feed and housing; stick on the converter and see what happens. At this point you have a fully functioning pen. If there is a component problem you will see it now.

If all is good follow his advice.

Bill


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## magpens

Please keep us posted ... would like to know what you finally come up with as the cause of the problem.


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## DutchPlatypus

Duncan & Bill,

Thank you for your insights. I have taken close looks at the section more than once and while the converter is perhaps a bit loose in the bore at that end of the section, I have not had any ink leak into the barrel of the pen, only out through the nib. If the leak occurs in both pens, it is so little in one that it is not noticeable while it is very clear in the one that leaks. I can also tell a big difference in how often I have to fill the pen. I also verified that the converter is seated completely. The fit of the converter on the collector is not super tight and the converter does have a bit of room back into the barrel (length wise) but it has never come off the collector. Overall this leads me to believe that it is not connection between the converter and the nib unit that leaks but instead, that ink is leaking out through the feed.

I'm in the process of making a new feed and I have a medium nib unit that I will try to finish this week. I will look for a tighter converter and I will also try to loosen the cap threads on the M13 barrel a little to see if that makes a difference. I'll post my findings here when I learn more.

Best Regards,
Edwin


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## duncsuss

Ah - that is quite different than the scenario I thought you had described (which was ink leaking inside the barrel of the pen.)

So, what you have is ink leaking into the pen cap - I assume while it is capped, otherwise you would have written "it leaks all over my fingers" 

Did you make this feed yourself? You wrote "using JoWo nib units" in your first post, but "I'm in the process of making a new feed" in your most recent post. Just trying to figure out what the situation really is before trying to come up with a diagnosis and/or suggestion.


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## More4dan

Are you storing your pens cap/ nib up. Always a best practice. If the cap is too loose the ink will evaporate over time. 


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## DutchPlatypus

duncsuss said:


> Ah - that is quite different than the scenario I thought you had described (which was ink leaking inside the barrel of the pen.)
> 
> So, what you have is ink leaking into the pen cap - I assume while it is capped, otherwise you would have written "it leaks all over my fingers"
> 
> Did you make this feed yourself? You wrote "using JoWo nib units" in your first post, but "I'm in the process of making a new feed" in your most recent post. Just trying to figure out what the situation really is before trying to come up with a diagnosis and/or suggestion.



I'm sorry Duncan, I meant to say that I'm turning a new section, not the feed. The feed is the standard feed that is part of the Jowo nib unit. Oh and yes, the ink leaks in the cap and onto my fingers when I take the cap off to start writing.

And Dan, when I run around with my work backpack (laptop case), I don't pay much attention about the orientation of the pen. For the most part I store it horizontally in my bag. However, I think the shocks from setting the bag down and even picking it up, may play somewhat of a role. I'm not entirely sure on that yet.

Best Regards,
Edwin


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## darrin1200

Another consideration, is what ink you are using. The viscosity of inks can vary slightly. I have used some inks that always seep a little, and get all over the top of the nib, can be a little messy. Other inks have to be started by turning the converter handle..

Your method of transport is also a huge effect. If the pen is horizontal or upside down, and you bag is bounced, then gravity will not be your friend. Just as if you held the pen upside down and gave it a shake, ink will come out.  I have been having similar issues with the mini pen I posted a few weeks back. It is intended to be a pocket pen, but when I carry it like that, I get some ink in the cap.


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## Sprung

I agree with Darrin that the way you're transporting them has huge effect. Try making a conscious effort to transport them nib up and see if that solves your problem. If I've transported filled fountain pens horizontally, or even had them somehow end up orientated nib down, it has usually resulted in ink in the cap and on the section - and then on my fingers.


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## DutchPlatypus

Darrin and Sprung, thank you for your feedback. 

I have used two kinds of ink in this pen, Diamine Kensington Blue and Waterman Serenity Blue. I have used both inks in both pens to see if there was a different behavior. The leak effect was the same for both inks, no leaking in one pen and leaking in the other.

As for the transportation issue, I am well aware of the risks of transporting a pen horizontally or nib down and I agree with your assessment that it is best to keep the nib pointed up. That said, I have carried all my pens the same way for years and I have rarely seen a leak. I carry four pens in the same pouch and none of them leak. I also carried both pens in my comparison the same way in the same bag. The 1/2-20 cap thread one never leaked (that I could see) and the other one does.

So far I’m still leaning toward the tightness of the threads as the main difference between both pens. I’ll have to make some time to try cutting the threads on the barrel just a tad more.


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## duncsuss

DutchPlatypus said:


> So far I’m still leaning toward the tightness of the threads as the main difference between both pens. I’ll have to make some time to try cutting the threads on the barrel just a tad more.


I'd spend some time looking at the cap too. I aim to have the minimum internal air cavity - which usually means drilling with several bits, one to clear the nib but touch the tip of the section, one to clear the section and take the cap threads (and maybe a third for the finial that holds the clip ring in place). Caps that are tight fitting don't just help prevent the nib from drying out, they help by creating a small pressure zone that might keep ink from leaking into the cap.


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## darrin1200

I would agree with Duncan on that. My plan for the next version of my pocket pen, is to try a lip that the section presses against to create a small sealed space.


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## Curly

Darrin I have a couple Sheaffer's that have the same kind of shoulder in the cap for the front face of the section to bear against. But that's likely where you got your inspiration from eh?


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## duncsuss

Curly said:


> Darrin I have a couple Sheaffer's that have the same kind of shoulder in the cap for the front face of the section to bear against. But that's likely where you got your inspiration from eh?


My Sheaffers don't have that (they are push-on metal caps). I got my inspiration from a guy called David Broadwell ...


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## darrin1200

Curly said:


> Darrin I have a couple Sheaffer's that have the same kind of shoulder in the cap for the front face of the section to bear against. But that's likely where you got your inspiration from eh?


It was a vintage pen that gave me the idea, but I cant remember which one.


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## Curly

Perhaps one of these? Notice the little hole in the cap. There is another on the opposite side. I think it is to release pressure while screwing the cap on and off. It is between the thread and shoulder the section seats on allowing air out until the shoulder seats sealing off the nib. The pic with the cap off is to show roughly where the two are when put together. 

The other pen is more recent and doesn’t have the little holes.


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## duncsuss

Curly said:


> Notice the little hole in the cap. There is another on the opposite side. I think it is to release pressure while screwing the cap on and off. It is between the thread and shoulder the section seats on allowing air out until the shoulder seats sealing off the nib.


This is a lever-fill pen, meaning there is a latex sac in the body of the pen. You operate the lever, which pushed against a springy J-bar inside the barrel, which in turn squeezes the latex sac expelling whatever is in there out through the nib. When you release the lever, the J-bar springs back to its resting position, and the sac inflates -- pulling in whatever surrounds the nib.

The slot in which the lever is recessed means that the pen barrel is not sealed. The latex sac is therefore constantly exposed to ambient air pressure.

Those holes in the cap were made to ensure that the nib of the pen is always at the same ambient air pressure as the ink sac. If they weren't there, the air cavity inside the cap (when it's screwed on tight) would be at whatever the air pressure was last time the pen was capped - and when you unscrewed a cap without breather holes, you could end up with a nasty ink burp if the air pressure had increased.


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## Curly

Thanks. That fills in a few blank spaces. Wouldn’t the cap pressure have a similar effect on a cartridge or converter too?


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## duncsuss

Curly said:


> Wouldn’t the cap pressure have a similar effect on a cartridge or converter too?


Not nearly to the same extent, if at all. Cartridges are much stiffer than latex sacs, converters are barely flexible at all -- so changes in the air pressure around them don't have nearly the same impact on the internal pressure.

If the cap of a converter pen is drilled, the pressure at the nib will change but the pressure inside the converter doesn't - until the difference in pressure moves some air or ink to equalize it. That could be an air bubble pushing into the converter -- or it could be a drop of ink burping out of the feed into the cap cavity.

Which leads to one possible solution to the ink-in-the-cap problem: since it's aggravated by air pressure differences, keep the converter full of ink (more precisely, "with no air in it") and there will be nothing to expand to force ink out through the nib.


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## DutchPlatypus

OK, a quick update. I chased the threads with the die backwards (saw this in a video on YouTube) which shaved away just enough material to loosen the threads a little. I have since carried my pen as I always do and it appears to be much better. I have only seen one more leak but I could make myself believe that this was after an 'excessive' hard hit on the table. I'll keep an eye on it for some time longer and post updates here if I learn anything more. Thanks everyone for all your feedback.
Edwin


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## PFMan

DutchPlatypus said:


> OK, a quick update. I chased the threads with the die backwards (saw this in a video on YouTube) which shaved away just enough material to loosen the threads a little. I have since carried my pen as I always do and it appears to be much better. I have only seen one more leak but I could make myself believe that this was after an 'excessive' hard hit on the table. I'll keep an eye on it for some time longer and post updates here if I learn anything more. Thanks everyone for all your feedback.
> Edwin



Can you link the video you mentioned, please? It could be interesting.

Thanks


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## DutchPlatypus

PFMan said:


> Can you link the video you mentioned, please? It could be interesting.
> 
> Thanks
> 
> 
> Sent from my iPad using Tapatalk



I don’t have a link but if you search YouTube for “rjb woodturner kitless”, you’ll find the videos that I used to make my kitless pens.


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## PFMan

DutchPlatypus said:


> I don’t have a link but if you search YouTube for “rjb woodturner kitless”, you’ll find the videos that I used to make my kitless pens.
> 
> 
> Sent from my iPhone using Penturners.org mobile app



I will take a look.

Thanks!!


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## Carl Fisher

I realize this is an old thread, but speaking from experience here. The biggest cause for leaks on a Jowo unit are either a cracked housing which is often hard to spot unless you intentionally try to separate it a bit or improperly inserted nib/feed into the housing. i.e. upside down, crooked, nib not placed properly on the feed, not inserted all the way, etc...

I suppose it could be a bad feed as well but that's not that common with the plastic feeds. If you're using an ebonite feed you may need to heat set it.


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## peytonstreet

Curly said:


> Perhaps one of these? Notice the little hole in the cap. There is another on the opposite side. I think it is to release pressure while screwing the cap on and off. It is between the thread and shoulder the section seats on allowing air out until the shoulder seats sealing off the nib. The pic with the cap off is to show roughly where the two are when put together.
> 
> The other pen is more recent and doesn’t have the little holes.



I was making blow fillers and button fillers for vintage flexible nibs and vintage feeds, and I did find some ink pooling on the nib. This problem disappeared when I drilled a breather hole in the cap. My threads are pretty fine and tight (cap-to-barrel threads) and I do believe pressure is created and relieved when capping and uncapping, so a vintage nib/feed set up to be wet to accommodate flexing are going to be susceptible.  It's not a problem we see with JoWo #6 nib units, however.


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## duncsuss

peytonstreet said:


> I was making blow fillers and button fillers for vintage flexible nibs and vintage feeds


Again -- ink sacs, not cartridges or converters, just like the lever fill pen that Curly pictured earlier in the thread.


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## DutchPlatypus

All, thanks for your suggestions and feedback. I did rerun the barrel threads (cap-to-barrel) to loosen them up and it solved the problem completely. No more ink building up in the feed or on the nib. I apologize for the delayed update. I tested this for weeks but forgot to post this update.


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