Help with way too wet, drippy Vacumatic

[azkid]

Me again with this 1944 Vacumatic.

The problem is that the pen allows a significant amount of ink to build up in the feed and it writes *really* wet and is extremely drip prone.

The pen is unusable with Quink Black, slightly better with Pelikan black and almost tolerable with Lamy Black but still builds up a huge amount of ink around the feed.

When I orient the pen nib up, the ink drains back into the barrel. Nib down, the ink pools up again with seconds.

If I start writing after nib up it acts like a normal pen but within seconds the fine line becomes a M and very wet.

Hoping you can help me troubleshoot.

I don't think it is a nib tuning issue. I've tried adjusting that but the ink pools up no matter how the nib is set up.

Could it be an air leak?

I've used Pentooling Super Slick Silicone Oil on the threads of the section as well as on the diaphragm and the threads of the plunger assembly. Maybe the use of silicone oil was unwise and I should reassemble using rosin thread sealant.

The breather tube is snug in the section.

What other air leak is possible?

Could the feed be wrong?

Do Vacumatic pens come with two feeds types, one for large nibs with high flow (deep air channel), one for small nibs with low flow (shallow air channel)? I read that was true for Challengers. This Vacumatic pen has a fine nib.

Thanks.

[AzJon]

I'll be curious to see the answer here. I've had pens that behave that way and I usually try to correct the problem with inks, but it is an interesting phenomenon.

[Ron Z]

Silicone oil certainly is not a thread sealant, and I would argue that neither is silicone grease. Bees wax is better, thread sealant is best.

Most of the time a leak like this is caused by something allowing air into the pen. Most common is a problem with the sac or diaphragm, and a cut across the seat ring in the barrel can cause it to leak as well. Start by replacing the diaphragm, and make sure that the seat in the barrel is clean. i.e. all of the old diaphragm removed, and smooth. If you have to remove remains of the old diaphragm, scrape around the seat, not across it. Put some water based personal lubricant (like Astroglide) on the outside of the diaphragm just over the cone area before you put the filler back in. That lets the diaphragm slide down the seat in the barrel so you can snug down the filler. Parker said to tighten the thread bushing "with firm pressure" though they didn't define that. Snug, but not torqued down really hard. Too tight and you'll distort or crack the barrel.

Seal the threads when you put the section back in, and then check to see that the feed is set against the nib properly.

An air channel that is cut too deep can cause the pen to flood, but that is one of the least common causes of the problem.

[azkid]

Ron, thank you!

I took down the pen and reassembled with rosin thread sealant at both ends and it is acting like a normal pen!

Whereas Quink Black was unusable before, it no longer pools at the nib, isn't drippy, and the pen is writing with a normal flow.

I was also able to seat the nib a few mm deeper into the section than before which was a separate issue.*

No more chance of the nib getting wrecked when capping and I can confidently cap it tight so maybe it won't dry out overnight like before.

I was seriously thinking about selling it in despair. Now I'm over the moon. I can relax and use and enjoy. This right oblique nib is gloriously smooth and springy and adds nice character to my writing.



* On a side note I am going to say once again that these little bullet sized IR touch-less thermometers make it so much easier to precisely heat up pen parts. I never have to worry about over cooking now. Heck, maybe I will try removing more 21 hoods...(not really; I'm not that much of a sucker for punishment)

[Ron Z]

Glad to hear that your problem was solved!

As a side note, you didn't harm the pen by using thread sealant on the filler end, but neither is it needed, or recommended. The diaphragm is firmly clamped between the ring in the barrel and the cone on the filler. With the filler tightened down it works as a gasket, so ink can't get out, and air can't get in. Having a fairly smooth surface is why you you should make sure that all of the old diaphragm is removed. Don't ever use shellac on the threads or on the diaphragm.

I should add that its important that the thread bushing spin freely on the cone. If it doesn't, the cone will turn as you tighten the thread bushing down, which can make the rubber on the diaphragm bunch up or tear.