Kaweco Dia 85 piston.

[Ondina]

Anyone has experience in replacing the corks/seals? This one spits ink by the rear seam when you operate the piston. If submerged in water, when the piston is turned air bubbles and a hissing sound come from the groove in between the barrel and the band where the name of model/nib is engraved as well as from it and the piston knob.

 

Nib unit screws/unscrews fine, no leaks.

 

Thank you in advance.

[RevAaron]

I've an 85 that I've not gotten to, but I have repaired the pistons of a few other Kawecos. Same deal- unscrew the piston assembly and replace the cork with a new cork or something synthetic. I don't have a lathe, so the corks I've fit were sanded down by mounting it onto on a Dremel mandrel. I've tried to find O-rings the right size to do something like David Nishimura's Nozac repair. Haven't had the time to go after it properly, and what I've had around hasn't worked out so far. It would be a lot less work than turning a new cork, though!

 

Careful with the nib unit- it's pretty easy to pull the nib/feed out from the collar. Once it's out, it's a pain to get it back in as firmly, and in doing so you'll risk cracking the collar. Just a head's up.

 

 

Aaron

[Ondina]

Thank you Aaron, I actually fiddled with the nib/feed/collar before reading your reply, and everything went fine, although I agree with you some finesse is required due to the delicate -but efficient- assembling of the parts. The nib is an as new vintage broad that flexes to a generous BB, I have the impression you would enjoy it

 

Concerning the piston, unscrewing it safely is my main concern, although turning a new cork accurately has also crossed my mind (as well as using the Dremmel for the purpose). Thanks for the heads up on the o-rings, much appreciated.

[Ondina]

Well, last week the pen went to the work bench and it's been one surprise after the other.

 

a. Piston unscrews turning the band at the back of the barrel, by simple rotating it counterclockwise. The whole pen, threads, barrel, piston parts...are in excellent -they look new- condition.

b. The piston has two parts. The one attached to the upper band and turning knob, hollow with a screw that rotates by turning the knob. Other second piece, also hollow, with an inner thread that goes into the upper screw and rotates with the knob/screw.

c. There is no cork!. The second piece of the piston ends in a cylinder surrounded by a rubbery material, like cloth.

 

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina198.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina201.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina202.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina203.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina205.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina206.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina207-1.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina210.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Pascuaypiscina212.jpg

 

Anybody has a suggestion for replacing the sealing band with a new material that effectively seals the piston while is being operated? I assume pistons without a cork are unusual. Anyone knows what's the original rubbery material?

[hamadryad11]

This is so interesting! I have a Kaweco Dia 85 that got fixed by Richard Binder (it needed to be retipped too). I had no idea how it came apart. I'm fascinated. I hope I can get my hands on one of these to take apart some day.

[Ondina]

This is so interesting! I have a Kaweco Dia 85 that got fixed by Richard Binder (it needed to be retipped too). I had no idea how it came apart. I'm fascinated. I hope I can get my hands on one of these to take apart some day.

 

It is, indeed!. I was thrilled to find the innards are so incredibly well preserved but for the seal band. The material (plastic? celluloid?) is very warm, feels like ebonite. Collar is celluloid & feed is ebonite and all the threads & parts look as they had been turned yesterday, very clean. The hallmarked Kaweco nib is a great vintage, stubby B with some flex (semiflex) and has plenty of iridium. The ink window is a bit ambered.

 

What really struck me was first, that the piston came apart so easily (pen was ultrasonically cleaned by a friend) and the singularity of the design. I've read somewhere there were some pens made in Czechoslovaquia that also used a similar system, but had never seen one in person. Now, the soft rubbery cloth, no idea what to replace it for. I even thought at first glance that it was a very badly deteriorated rubber band. I hope somebody chimes in with a suggestion, the pen is really a worthy piece.

Edited May 14, 2009 by Ondina

[fountainbel]

I would not hesitate to replace the rubber seal with a cork seal !

Alternatively you might look for a fitting standard O ring ( and possible also add a nylon washer coping for the smaller thickness of the O ring compared to the oroiginal seal)

Francis

[Ondina]

Thank you, Fountainbel, both possibilities had crossed my mind, but turning a cork ring is well beyond my possibilities. I will start looking for o-rings and such at the nearby plumber's shops, but getting some so small is not easy (I've tried before, for a Le Man 200 barrel, without any luck).

The advice, coming from, you is very much appreciated.

[piembi]

Congratulations!

And great pics!

 

This might encourage me to give my junker Dia another try - although this one has resisted every attempt of uncrewing the barrel so far :mad: . If I can get the piston back to working order I might start looking for a replacement nib ....

[rhosygell]

Car parts stores / warehouses are a good source of small o rings as is your local hydraulics specialist.

 

Failing that find some wad punches (hollow punch) and cut a suitable replacement out of a flat bit of thick rubber - doormats are ideal for this purpose. It works.

[Ondina]

Congratulations!

And great pics!

 

This might encourage me to give my junker Dia another try - although this one has resisted every attempt of uncrewing the barrel so far :mad: . If I can get the piston back to working order I might start looking for a replacement nib ....

 

Thank you ( for the praise and for the cleaning!). May I suggest helping to loosen up the barrel with some gentle heat after trying the ultrasound once more?. You know far better than myself how this works, so... Let us know!

[Ondina]

Car parts stores / warehouses are a good source of small o rings as is your local hydraulics specialist.

 

Failing that find some wad punches (hollow punch) and cut a suitable replacement out of a flat bit of thick rubber - doormats are ideal for this purpose. It works.

 

Much appreciated suggestions, rhosygell, both are great ideas. I'll see what I can get and report back with any progress.

[piembi]

Congratulations!

And great pics!

 

This might encourage me to give my junker Dia another try - although this one has resisted every attempt of uncrewing the barrel so far :mad: . If I can get the piston back to working order I might start looking for a replacement nib ....

 

Thank you ( for the praise and for the cleaning!). May I suggest helping to loosen up the barrel with some gentle heat after trying the ultrasound once more?. You know far better than myself how this works, so... Let us know!

 

Would have been my next step. Thanks for the affirmation

Pen went into the US cleaner this morning and I will proceed at the weekend ....

[hamadryad11]

You know, seeing this has made me want to get some more vintage Kaweco piston-fills. I really like the one I have, even if it's not the prettiest pen in my collection. Now that I know it's not too hard to open one up, I will have to look around for some that need work and try fixing them myself.

 

I wonder what Richard Binder uses to fix these. My ink window is very dark and stained from decades of old ink, so I can't see very much when I lower the piston.

[Ondina]

I wonder what Richard Binder uses to fix these. My ink window is very dark and stained from decades of old ink, so I can't see very much when I lower the piston.

Cautionary note: Not all Kaweco Dia use the same piston system, this is not an usual one, most I've seen are either friction fit or even welded -they need to be soldered after the repair- and many, have a screw gauge at the end of the piston that must be accessed from the bottom opening of the barrel in order to open it without damage. The friction fit ones are specially delicate. So please keep in mind that if you get another it may end up needing a professional restauration ( I would hate to dissapoint anyone reading this and thinking they will get an exact piston. This is a non usual variation, for what I've read).

 

I've also wondered what professional restorers use. A whistler-blower hinted me the same material that they use for repairing vacs was the one to be employed in this repair. Unfortunately, I know nothing about vac repairs, either. :embarrassed_smile:

 

Concerning the ink window, even the brand new 85's had a quite dark yellowy brownish window, so if it ambers a little more is quite hard to see the ink level unless you put it agains a strong light source. There was a thread here a few days back of a member stating he was testing products to solve the ambering in pens with good results, if I recall correctly. I'm sure every pen repairer has its methods but obviously they are not too prone to share them here or they would soon run out of business. Maybe a chemyst with knowledge of plastics& celluloid could suggest us what to use -obviously no alcohol, etc. is advised, I'm aware of it-.

[gds]

I'll be watching with interest to see if you can find a nice way to fix this. I have an old Senator pen (which looks like the Kaweco Sport) and the piston looks very similar to this - dismantles just the way you are describing, and the piston head has the same rubbery material. Mine needs to make a better seal as well. I was planning to send it for repairs some day because I don't have any tools to fabricate a new cork seal. Maybe I should be looking for a suitably sized O-Ring.

Edited May 15, 2009 by gds

[Ondina]

Update: some rubber gaskets of appropriate diameter were finally found yesterday afternoon at a plumbing supplies store. The two smallest sizes were:

5.28x1.78 cm

6.07x1.78 cm

 

After testing them in the piston's rod, the 5.28 seem to be the ones.

 

Now, several finds came with the practical part. First, the rubbery material is cork. A very deteriorated, ossified but undeniably a cork ring. Both the inner and outer surface have a blue-black tint, more than probably from the inks used in it.

http://i348.photobucket.com/albums/q347/Ondina_2008/Kaweco001.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Kaweco003.jpg

 

After the cork disintegrates under minimal pressure, it reveals there is a plastic washer.

http://i348.photobucket.com/albums/q347/Ondina_2008/Kaweco005.jpg

 

3 O-rings fit perfectly in the space left by the cork, but (big but here) their outer diameter is about .7 mm bigger than it should. Silicon grease dos not help.

http://i348.photobucket.com/albums/q347/Ondina_2008/Kaweco006.jpg

http://i348.photobucket.com/albums/q347/Ondina_2008/Kaweco008.jpg

 

The friction is too much and is not operative inside the barrel. So, I clearly need a cork. Anyone knows where I can get one? Turning it myself is beyond my abilities, I'm afraid. Sanding the o rings to make them flush with the inner wall's diameter won't work, the first experiment with one just peeled the rubber and destroyed it.

 

 

[fountainbel]

Hi Ondina,

Ideally you should have a radial O ring pretension of 0.2mm.

Given the dimensions you specifeid , a "standard *" (*at least in Europe ) O ring of 5x 1.5mm might do the job.

In order to restrict the friction - hence the filling actuating toirque- you should only install one Oring, since the friction is triple as high when ussing 3 Orings.

Add a nylon ring behind the Oring to compensate for the smaller width of the seal.

Francis

 

 

[Ondina]

Thank you, Francis, it seems my best effort on getting small gaskets was the present ones, I have checked several catalogs and no luck on finding thinner ones. If anyone could point me to those, It would be great. Or to a cork, which may be even better.

Installing a nylon washer will be an issue: the "free" lower end has a ridge and the "long" lower one that extends to the rod, has a washer already that is the one that serves as a stopper. I don't see the way to getting anything non elastic in there, but for cutting it and re-gluing it once installed.

 

Thanks for the input, and excuse my inexperience in such tasks.

Edited June 13, 2009 by Ondina

[fountainbel]

Attached a US link shoiwing 2 sizes which will help you out :http://www.oringsusa.com/oringsUSA_O-Ring_sizes.pdf

In the metrric sizes there is 5x1.5mm

In the inch sizes there is 0.2" x 0.062" ( 5.1x1.6mm)

When you are in Europe you can Google for Eriks Orings

Francis