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Early Plastics - 1940S - Early 50S Question


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12 replies to this topic

#1 Ray-Vigo

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Posted 21 August 2019 - 14:41

One thing that I've noticed but never bothered to ask about is the relationship between the color of the early "plastic" pens and deterioration of the plastic material over time. I'm talking here about the solid colored plastics of the late vac-fill pens, the fat Touchdowns, and the TM Touchdowns. I've seen that the material seems to shrink and (at worst) crystallize and go brittle over time.

 

I've got several Touchdown pens where there is a bulge at the point that the barrel gasket sits, where the barrel has shrunk around the gasket, forming a "ring" shape on the outside of the pen. At this point, the barrels on some of the pens are weak and brittle. Most of the pens I've come across are still functional, but some are so brittle that they crack or break when you go to remove the old gasket. I had one dark green pen were the whole back part of the barrel came off with the gasket.

 

You see it on the plastic caps as well. You'll see areas on the green and the blue pens that are darkened and which seem to have shrunk. Again, the greens seem the worst, followed by the blue and then the red  and finally the black. The black again seemed to shrink the least.

 

So the worst of them seem to have generally been the dark green ones, with a couple of the dark blue pens having issues. The black pens seem to have fared the best. The dark red is somewhere in the middle.

 

Of the different generations, the TM Touchdowns seem to have the fewest problems, with the fat Touchdowns having more shrink issues than the TM, again in my experience.

 

For people who have seen many of these pens, is it also your experience that the dark green plastic seems to age the worst, whereas black seems to hold up the best? Was there any difference in the material used to color the plastic when they made these?


Edited by Ray-Vigo, 21 August 2019 - 14:44.


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#2 pen2paper

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Posted 22 August 2019 - 01:13

Others will give specifics related to specific pens, but in general if you search museum conservation care of plastics, it's an issue to stabilize deteriorating pieces, manufacturing, curing, use, care, storage, temps, & enclosed with what other materials, destabilized structure plasticizer migration to fail. Irony that we're also concerned about longevity of plastics refuse.

In other mixed materials objects, metal, plastics, rubber, pearl, its advised to provide airy ventilation, low indirect light, moderate temps, & absorbant packs - desiccant, or interleaving, & store by material rather than color. Rare fragile plastic, I'd remove sac to store.

emoticon-animal-007.gif~Hi! fountain pen enthusiast here~


#3 Vacumagi

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Posted 21 November 2019 - 04:20

Hi folks - this is my first post here. I've got a dark green Tuckaway (touchdown filler) from the same era as the "fat Touchdowns" that has shrunken plastic around the O ring gasket forming a raised rib on the outer surface of the pen. It is very hard to fill and to operate the Touchdown filling mechanism. Other than that the pen is really good and I would like to get it working as a pen that I can carry a lot. 

 

Is there an approved repair method? I was thinking of apply controlled heat and to use some sort of wedge to stretch the plastic back out, but I am afraid I will break it. I am torn between trying to repair it and just leaving it as it and not using it much. The color of the dark green is very nice - just have that shrinkage problem.



#4 Ray-Vigo

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Posted 21 November 2019 - 13:49

I have experimented on a couple of old barrels doing that kind of thing - trying to soften the plastic around the o-ring a bit. Now these were some of the worst barrels I had, so it might not be a fair sample, but I had no luck trying to improve the plastic shape around the o-ring. The shrinking seems to be widespread and in the worst cases, the plastic also crazes and goes brittle in the area. Maybe a better condition barrel would be a better candidate, but the junker barrels I had did not want to become truly "workable" around the ring. I have a few pens that are like yours with the ridge at the o-ring, and I ended up just leaving them - still was better than the results of my experiments with the junker parts.



#5 tamiya

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Posted 21 November 2019 - 20:59

Plastics usually just shrink further if you try heating them towards plasticity stage without something (mold, mandrel, form etc) of the right size for it to form to - then let cool.


But wait...

Plastics have shrunk with age. The bit that didn't is the bit in contact with the pressure sealing o-ring, right? The plunger has held it out at original size. So IMHO that wide bit is original size... not as if what's inside has grown bigger & causing hernia.

Shouldn't you be trying to expand the rest of the narrow bits to match the wider bit instead?

#6 Vacumagi

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Posted 21 November 2019 - 23:21

Okay, I figured out a solution. It's a kludge, and I'm sure that after 70 years, I've invalidated the lifetime warranty, but now I have a pen that I can fill with ink and use and I love it. What I did was to chuck the plunger in my woodworking lathe and sand the plating off the plunger, then resmooth it with up to 2000 grit automotive sandpaper. It works! I can operate the plunger easily, now, and it makes a good overpressure, then under pressure for the sac to allow it to get a good fill with ink. I only needed about a reduction of a 10th of a millimeter in diameter to get the plunger to work smoothly. I chose to do this instead of trying to adjust the plastic. The pen came to me with a cap that is, I believe, for the Tuckaway ballpoint pen of that era. It has the little brass boss underneath the white dot. If I'm wrong about this, someone please let me know,....The cap still gives you an airtight seal, but I will be searching for the correct one. I love my new carry-around 70 year old pen! Photo of the pen is the one in my profile photo.



#7 Vacumagi

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Posted 22 November 2019 - 00:17

Photos attached. You can see that raised area where the o-ring seal is that indicates overall plastic shrink. IMG_1567.jpg IMG_1568.jpg IMG_1566.jpg



#8 tamiya

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Posted 22 November 2019 - 05:57

Whats the plunger made of, rubber?

Or do you mean its a hard body-plastic holding an o-ring and you shaved down the plastic, letting the o-ring seat tighter in.


Maybe if we can get it (the actual sealing part) copied into a gummier material like silicone itll seal across a wider range of tolerances.

#9 bhbarto

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Posted 12 December 2019 - 20:57

I have a bit of swelling/shrinkage in the same area of my 1950 Valiant TM which does not seem to affect the pen yet.  I have never seen this in any of my snorkels, which are essentially the same pen.  Different plastics maybe?


Pen(s) Currently in Rotation:

Parker "51" (Fine) - Waterman Blue-Black

Sheaffer TD Valiant TM (Fine) - Waterman Blue-Black

Sheaffer TD Statesman Fat Model (Fine) - Waterman Blue-Black

Sheaffer Snorkel Desk Pen (Medium) - Cult Pens Deep Dark Brown


#10 Parker51

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Posted 13 December 2019 - 02:43

Maybe, or maybe age. This is not just a Sheaffer issue. Problems regarding plastics have also been noted with other brands and other colors. I know one person who sells pens he acquires Of another band as soon as he can because he is afraid they will disintegrate on him.
And, don't forget the problem with certain early Sheaffer Balances. Yes, a different kind of plastic and one no longer used much, but one that must give us all pause. I personally had an Oversize Balance in one of the known unstable color combination develop a crack and drop off a piece of cap lip through occasional gentle use. I will also not post the modern ones I have due to their known propensity to do the same thing, crack and fall to pieces.
I expect that all fountain pens will eventually disinigrate, it is only a matter of how long. With some, it may be as little as twenty years, some seventy, some a hundred and fifty and perhaps some a thousand, but unstable chemical reactions such as those involving plastics mean eventually they will disinigrate.
So, I suggest enjoy your pens today, preserve them the best you can and hope for someone to someday come up with an affordable way to restore them.

Edited by Parker51, 13 December 2019 - 02:45.


#11 Garageboy

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Posted 16 December 2019 - 22:15

Makes me weary about putting my vac fill blue valiant into service, but I figure it's gonna degrade with or without me

#12 BrianMcQueen

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Posted 08 January 2020 - 22:15

There is something about the early "Forticel" plastic, introduced in 1947, and used through 1951.  It seems to shrink around the o-ring area and the inner cap.  I guess they reformulated the plastic for the Snorkel, because the colors are different and I do not see the same shrinkage in Snorkels that I regularly do in Thin Model Touchdowns.  They must have changed the thread and trim rings as well.  Thin Model Touchdowns tend to pit and flake the chrome plating, but Snorkels do not have this issue.



#13 Parker51

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Posted 09 January 2020 - 03:11

I checked and the plastic used, Forticel is a thermoplastic that is biodegradable. A new version of it made from corn in a single reaction rather than cellulose and propionic acid may be coming out for food packaging. Propionic acid, in addition to being needed to react with cellulose to form a plastic is a preservative used in food production.
In regard to reforming it, good luck, as it was injection molded at very high pressure and temperature.
The good news is at the levels of venting that occurs with the plastic over its lifetime, it is harmless as far as human health goes and it naturally deters mold growth.

Please remember that at the time these pens were made automobiles, which were significantly more expensive typically lasted no more than a decade or about 100,000 miles. And they required a lot more maintenance and replacement of parts. So, a pen that lasts 70 years is actually quite good.

Maybe what we need to do is figure out how to replace the plastic when it crumbles and returns to cellulose. Perhaps 3D printed replacement parts?






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