Crack In Barrel Threads In Piston Filler

[penspouse]

I just purchased an older German piston fill pen from another FPN member. It has a crack in the barrel threads, and thus leaks ink. I love the pen and the nib and don't want to give it up. Hubby has done some pen repair and is willing to try this, but we need to know the best way to go about repairing/sealing the crack, and what to use. The nib screws out like a Pelikan, and the threads are between the section and the body. Any help would be appreciated.

[FarmBoy]

I just purchased an older German piston fill pen from another FPN member. It has a crack in the barrel threads, and thus leaks ink. I love the pen and the nib and don't want to give it up. Hubby has done some pen repair and is willing to try this, but we need to know the best way to go about repairing/sealing the crack, and what to use. The nib screws out like a Pelikan, and the threads are between the section and the body. Any help would be appreciated.

 

The first approach would be a solvent weld of the crack with attention to maintaining the thread profile. You will need to carefully select the solvent (you don't mention the material) and there are some materials that will just not weld well. Also older cracks that are dirty can be problematic.

 

Put up a picture of the crack and such. You may also have luck finding a replacement barrel, moving a nib/feed/section from one pen to another is often easier than fixing a crack.

 

FB

[Chthulhu]

If you have the wherewithal, adding a band there will help reinforce the repair.

[Chevalier]

Just don't try to use superglue before you know the material. I had a pretty bad experience with it before I knew more about solvent welding and glue sealing.

[ttakacs]

Search this forum for "methyl ethyl ketone" and "MEK". I repaired a 1 cm crack in the barrel of a Lamy Artus piston filler by brushing some Oatey PVC Cleaner (a mixture of acetone and MEK) in the crack using a fine artist's brush. The solvent melted the barrel plastic ever so slightly; by squeezing the crack the solvent knitted the crack shut. I waited 12 hours and reapplied and got a permanent seal. Most folks will say that if the repair is structural to wait seven days before testing. The downside is that marring the plastic finish is nearly unavoidable. Fortunately, the pen is black and the marring is barely noticeable -- you have to look carefully to see it.

[penspouse]

Hubby was checking the pen out yesterday and put it where I can't find it. He's at work so, I won't have access until this evening. This is a picture of it snipped from the original FPN listing that is no longer active. Don't know if anyone will be able to identify it or know the material from which it is made.

 

ETA: FarmBoy - There is no way to get a picture of the crack. It is so small it can't be seen. We found it by blowing air into the barrel and seeing water bubbles come through the crack (I had just flushed it).

 

ttakas - The threads are black. If we can get this fixed, I don't think it will be noticeable.

 

Edited August 4, 2011 by penspouse

[Ron Z]

The pen is most likely celluloid. MEK is the best stuff that's available to you, and would be the best to use here. Get a roll of Scotch 33+ electrical tape while you're in the store buying it. Caution: MEK is nasty stuff. Wear gloves, an do it by an open window. You don't want to breathe the fumes - it's nasty stuff.

 

Make sure that you clean out any thread sealant before you try to repair the crack. Expect to apply thread sealant after when you put the pen back together.

 

Use an artist's brush (soft camel hair, maybe a little under 1/4") Spread the crack a bit from the inside, apply the MEK from the inside, let it close, spread and reapply. Then let is close. Wrap the repair with a couple of turns of the Scotch 33+, stretching it a bit. It will tend to pull back and will clamp the repair closed. Let it dry for at least a couple of days. A week would be better.

 

You will have to clean up the threads both inside and out to remove the excess. Be careful if you polish - it's easy to remove too much material and end up with loose threads.

 

... or you can send the pen to a professional who has a lot of experience repairing celluloid.

[penspouse]

The pen is most likely celluloid. MEK is the best stuff that's available to you, and would be the best to use here. Get a roll of Scotch 33+ electrical tape while you're in the store buying it. Caution: MEK is nasty stuff. Wear gloves, an do it by an open window. You don't want to breathe the fumes - it's nasty stuff.

 

Make sure that you clean out any thread sealant before you try to repair the crack. Expect to apply thread sealant after when you put the pen back together.

 

Use an artist's brush (soft camel hair, maybe a little under 1/4") Spread the crack a bit from the inside, apply the MEK from the inside, let it close, spread and reapply. Then let is close. Wrap the repair with a couple of turns of the Scotch 33+, stretching it a bit. It will tend to pull back and will clamp the repair closed. Let it dry for at least a couple of days. A week would be better.

 

You will have to clean up the threads both inside and out to remove the excess. Be careful if you polish - it's easy to remove too much material and end up with loose threads.

 

... or you can send the pen to a professional who has a lot of experience repairing celluloid.

 

Ron,

 

Thank you. Very helpful reply. I'm pretty sure Hubby has MEK and knows how to work with it. I'll show him your post and let him decide if he wants to tackle the job or send it out to be done.

[klangbogen]

Spouse of Penspouse here. This is a picture of the barrel and threads. There is a crack in the threads. This was confirmed when I blew air into the barrel with a bulb syringe. I placed a very small amount of soapy water on the threads and used the bulb syringe. I saw bubbles coming from a perfectly straight vertical crack almost the entire width of the threads. (The reflection line shown below the arrow approximates where the crack is) I also see 2 other straight "lines" that are perpendicular to the threads and similar to the crack. Under my microscope they appear as perhaps some sort of injection mold marks, or seams of some sort. They do not leak. The pen seems well made and I believe this hairline crack has made for some inky fingers and might account for why it seems unused.

 

Your thoughts are appreciated.

 

[Chevalier]

I already brought this up, but again ... is it bad to use GBL (Butyro-1,4-lacton, or gamma-Butyrolactone)? I already used it to weld resins together, but I'd like to know if Butanone (MEK) behaves better.

[Chi Town]

Where does one buy the materials that are being talked about in this series here?

[watch_art]

I've been told that model cement from a hobby shop is the same thing as MEK. I don't know for sure. It's the heavy duty nasty stinky model cement for holding serious models together. I'd like to know if it's the same stuff, too.

[Sholom]

I already brought this up, but again ... is it bad to use GBL (Butyro-1,4-lacton, or gamma-Butyrolactone)? I already used it to weld resins together, but I'd like to know if Butanone (MEK) behaves better.

 

I expect Butyrolactone will take significantly longer to finish drying than would MEK (2-butanone). I know of at least one pen that resists both of them - the long forgotten Faber-Castell Higgins Pengraphic. Anyone know what that model (sold as a combination India ink technical pen and fountain pen back in the 1960s) might be made of?

[Chevalier]

PF-HD should resist both, lab chemicals are sold in PF-HD bottles too.

 

Oh, PF-HD is high density phenol-formaldehyde-resin (like Bakelite, just high density).

Edited September 8, 2011 by Chevalier