O-Ring Cap Seal

[Precise]

My TWSBI and Lamy Safari have O-Rings set in the barrel which engage the edge of the cap. Neither has ever dried up. Have you experienced dry-up with a pen which has an O-Ring caps seal?

 

This looks to me like a better design than the plastic seal on my Platinum 3776, which has dried up in weeks, despite the promise that it will write after sitting for one year.

 

I have a few Duke pens that write well, but have tended to dry up in a few weeks, so I machined grooves for O-Rings on two of them. I'll have to let them sit for a month to see if I've accomplished anything.

 

I should add, that most of my European and Japanese pens don't dry up, despite lacking O-Ring seals.

 

Alan

Edited October 18, 2015 by Precise

[kernando]

The Safari has a hard plastic trim ring on the section, right?

[Precise]

The Safari has a hard plastic trim ring on the section, right?

You are correct. It is hard. Mine is black and looks like rubber, but it's hard. However, despite being hard, it may provide a seal. The seal in most fountain pens is a hard plastic insert in the cap.

 

I checked my TWSBI VAC700. Its seal is a rubber O-Ring.

 

Alan

[graystranger]

My TWSBI pens all have O-ring seals for the cap PLUS they all have an inner cap seal too that contacts the front to the grip section. So, two sealing surfaces for the nib and feed. This includes two Vac-700's, a Mini, and an Eco.

 

Plus, on the Vac-700's, you can close off the reservoir so the ink in it does not flow into the feed and nib at all. In fact, you could close off the reservoir, flush out the nib and feed, and the Vac-700 would not dry out for years upon years (until its rubber seals deteriorate, capped or uncapped! You would just have to wait until the ink has time to flow into the nib and it would start writing right away once the seal is opened up.

 

i asked TWSBI how long their pens can go without drying out (because of the inner cap seal and the 0-ring seal), and TWSBI said they only tested their pens for two weeks capped, so they do not know how long they can go. But, I have left Emerald of Chivor in a Vac-700 for 3 or 4 weeks and the nib stayed perfectly wet and started up immediately on contact with paper. Wonderful pen designs.

 

My 3776 Century has never had the nib dry out, but it has not gone longer than several weeks at a time capped.

 

My Lamy Al-Star nib will dry out after a week or two capped. The cap may seal with the body, but the cap is not airtight at all. Suck on a Lamy cap and you can tell it is not airtight. I think it is the clip where air enters the cap.

Edited October 18, 2015 by graystranger

[kernando]

It most likely doesn't. Also, look for an inner cap, or look at the pictures people have taken of disassembled Safaris. It's probably the inner cap that snaps onto the end of the section.

[Algester]

My TWSBI went with 4 months inked and not drying... I'm amazed how good the seal is even if it's just "simple"

[Precise]

It most likely doesn't. Also, look for an inner cap, or look at the pictures people have taken of disassembled Safaris. It's probably the inner cap that snaps onto the end of the section.

 

Agreed. The Safari, and most snap-cap pens have a rounded annular groove at the bottom of the section which engages an annular ridge inside the cap. That's what makes it snap. And it could also provide some sealing too.

 

I thought that the black ring might be a "zero" fit to provide some (added?) sealing. But I measured my Safari with a caliper and the radial gap at the black ring is about .002". Several of my Duke pens have similar gap.

 

The Safari black ring is about 2mm wide. I've been putting 1mm wide O-rings on my Duke pens (I've done three of them). I could cut a 1mm O-ring groove right in the center of the black ring. But the pen hasn't dried on me. So at the moment, "If it aint broke, don't fix it".

 

Alan

[Precise]

Update.

The Duke pens, that I added an O-ring caps seal to, have now gone a couple of weeks without dry-out. I've since added O-rings to a couple more Duke pens.