# O-rings or not for eyedropper?



## Carl Fisher (Jan 2, 2015)

So when I make custom pens with the Esterbrook nibs, I have to either sac them or offer them as an eyedropper.

For the eyedropper conversion, is silicone grease enough or should I be incorporating an o-ring as well for the section to body joint.


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## Brooks803 (Jan 2, 2015)

If your threads aren't loose I'd say it'd be fine with just silicone grease. If you did start incorporating O-rings just make sure you can always find a supply of them for replacement parts down the road.


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## Carl Fisher (Jan 2, 2015)

I know the video from Brian over at Goulet shows him using an o-ring when he converts the Platinum Preppy which is why I got to thinking of it.

I have a request for one of my Esterbrook nibs and in talking with him about eye dropper pens, we got to discussing the need or not of o-rings.


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## duncsuss (Jan 2, 2015)

I've made a couple of pens with Esterbrook sections.

One is a bulb filler that uses the pen barrel as the ink reservoir just like an eyedropper. The section/barrel joint has M9x.75 threads, 5 full turns. No o-ring, but I do put a dab of silicone grease on there if I disassemble it (for example when I'm cleaning it out to change ink colour.)

It's been my daily writer for over a year -- I take it to work and back in my briefcase every day. No leaks so far.


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## Carl Fisher (Jan 2, 2015)

I was having a conversation with Jonathon earlier about that exact configuration.  Do you not need a breather tube to do a bulb filler? Having to modify an Estie nib with a breather tube would negate the benefit of having nibs easily exchanged as designed with the renew point lineup.


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## duncsuss (Jan 2, 2015)

Carl Fisher said:


> I was having a conversation with Jonathon earlier about that exact configuration.  Do you not need a breather tube to do a bulb filler? Having to modify an Estie nib with a breather tube would negate the benefit of having nibs easily exchanged as designed with the renew point lineup.



Since I didn't have a clue what I was doing, I was not hampered by the traditional wisdom ... :biggrin:

I found a way to do it which doesn't interfere with the Estie nib unit ...


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## duncsuss (Jan 2, 2015)

Check out my page on FaceBook, there's a photo album called "custom bulb filler prototype" ... link


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## Brooks803 (Jan 3, 2015)

Duncan, do you mind elaborating what you did with the breather tube? I checked out your album and it gave me more questions than answers, lol


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## Carl Fisher (Jan 3, 2015)

I was thinking the same thing.  Trying to figure out how that would work from just the front shot leaves me scratching my head :biggrin:


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## duncsuss (Jan 3, 2015)

Sure -- really it's dead simple.

I made a plug that fits into the rear end of the section (where the cartridge/converter would go) and drilled it to receive the flexible tube.

Glued the tube in place, then glued the plug+tube into the section.

Then I added the magic ingredient ... :glasses-cool: ... a pin hole in the tubing just above where it's glued into the plug, which lets the ink leak through and feed the nib unit. (It's very small in relation to the inner diameter of the tube, so when you squeeze the bulb it expels more air through the tube than ink through the pinhole -- otherwise you wouldn't be able to fill with ink.)

Maybe I am a rocket surgeon after all :biggrin:


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## Carl Fisher (Jan 3, 2015)

So the hole in the breather tube is feeding ink back down into the feed through the breather?  

I wonder if a small hole in the plug would be an alternative to that.


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## duncsuss (Jan 3, 2015)

Carl Fisher said:


> So the hole in the breather tube is feeding ink back down into the feed through the breather?
> 
> I wonder if a small hole in the plug would be an alternative to that.


Let's not call it a breather tube. It doesn't connect to the outside world the way I understand a breather tube does.

The tube's main purpose (IMO) is to expel the air from the bulb (instead of expelling the ink you just inhaled right out again) when you try to fill the pen.

Neither the tube nor the pinhole in the tube is passing ink into "the feed" -- it's just letting it leak into the cavity in the section behind the Esterbrook Renew-point.

A second hole through the plug would almost certainly work just as well at letting ink leak through to the cavity behind the nib unit, so long as it is small enough that more air than ink gets expelled when you squeeze the bulb. Maybe the mass of ink (compared to air) would do that automatically, inertia and all that.


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## Brooks803 (Jan 3, 2015)

Thanks Duncan. It took me a bit to grasp everything but it's making a bit more sense now.


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