Cracked Parker 51 barrel

[CVR]

Dang! Just cracked a pristine grey Parker 51 Deb barrel!

 

Finished replacing the diaphragm, and got greedy.  I was trying to get the blind cap aligned precisely, as it was before, and tried to get the filler mechanism to screw in to exactly where it was before I took it apart. It screwed in fine, and a few minutes later, the crack showed up. Obviously, I'd screwed it in too far. I'd also used thread sealant, so perhaps the radial forces were higher as a result.

 

Is this repairable using a solvent weld? If so, MEK or Methylene Chloride?

 

Or is it better to just get a new barrel?

 

 

 

 

[VacNut]

People are trying new solvents. The crack can be repaired but it will be visible. 
You applied thread sealant on the filler threads? I have never heard of that before. I know the thread sealant may be used on cap/clip jewels and on the base of the Vacumatic barrels at the section. 
The vac diaphragms self seal against the conical seat and the filler.

The gray 51 double jewel barrels have a greater tendency to split

[FarmBoy]

Replace the barrel. 
 

The orientation of the jamb nut should not matter. If the barrel and blind cap have not been aggressive shaped to line up then it will line up with little effort. 

[CVR]

Thank you both.

 

Yes, I have not previously used thread sealant when installing the filler, but when I took the filler out (took a couple of days of soaking+heat), I found myself scraping some sort of white material off the the filler threads. I don't think the pen had been serviced since 1947 (date on the nib), so I assumed the sealant was from the factory, and put some of Ron's sealant on when reinstalling it. I probably shouldn't have, and it may have increased the stress on the threads, but much more likely, I just screwed the filler in too far.

 

I'll try a solvent weld first to see how well it works, but it looks like I might need a replacement barrel.

 

Is there a recommendation for where I might look for a replacement barrel? Pentooling didn't have any, and a quick search didn't turn up anything useful.

[Ron Z]

The white stuff on the threads was corrosion.  The ink wicks into the threads when a diaphragm fails, and ink gets into the back.  That can cause the aluminum of the thread bushing to corrode.  Sometimes it's just a dusting, some times it makes it very difficult to get the filler out.

 

Parker's comment is that you use "firm pressure" when you tighten down the thread bushing.  I put some water based personal lubricant on the diaphragm in the area over the cone.  That allows the cone to slide down the ring into position when you tighten down the thread bushing. 

[CVR]

Thanks, Ron. That sounds like a likely explanation for the stuff in the threads, and why is was so hard to get the filler out. Here's the full story.

 

I put marks on the barrel and filler to get the alignment right. I used the collet vac extractor from The Inky Nib to get out the filler, and left it in place when working on the filler unit, so I could get it back to exactly where it was. I'd started with it flush against the barrel end, with the hope that screwing it back flush would put the filler back exactly where it was.

 

Replaced the diaphragm, cleaned out the barrel and seat, put talc inside the diaphragm and water-based lubricant outside it, but screwed the filler back too far, as shown by the alignment marks. I put the collet back, and backed out the filler a quarter turn, and that's when the crack showed up.

 

Ah well, one lives and learns, but I do feel terrible about ruining a perfectly pristine barrel.

[Ron Z]

I wouldn't go with the original mark.  The wall thickness of the diaphragm is likely to be different than the original, and may be from batch to batch.  Go by feel, not by original rotation position.  I have solvent welded barrels, but you have to be very careful tightening the filler.  That cone against the seat in the barrel is a wedge, so can create quite a bit of outward force.  Even if it doesn't crack, it can cause barrel bulge, especially on Vacumatics.

[CVR]

Thanks, Ron. I'll plan to use solvent on the outside of the barrel, but it seems better to also do it on the inside.

 

On the inside, the seat and the barrel part below it are both safe, but is it safe to solvent-weld the crack through threaded portion? Or is putting solvent there likely to ruin the threads?

[FarmBoy]

Contrary to the internet, 51 barrels do not solvent weld in nearly every case.  There have been a few documented cases where the barrel wasn't Lucite and a solvent weld was possible.  (An article on this will eventually appear in a pen related publication.)

 

If you really want to fix a 51 that has a crack in the filler threads you need to sleeve the barrel, make a new seat and recut the threads. 

 

OR just replace the barrel.

[CVR]

15 hours ago, FarmBoy said:

Contrary to the internet, 51 barrels do not solvent weld in nearly every case.  There have been a few documented cases where the barrel wasn't Lucite and a solvent weld was possible.  (An article on this will eventually appear in a pen related publication.)

 

If you really want to fix a 51 that has a crack in the filler threads you need to sleeve the barrel, make a new seat and recut the threads. 

 

OR just replace the barrel.

 

That's fair warning, and I'm certainly not equipped for that kind of work.