Early 1960s Pilot feeds: a tale of plastic that turns to mush :shocked:

Well, a new shipment of cool older Japanese pens arrived on my doorstep late last week, which was great!

However, much to my dismay, two (and maybe more) of the pre-1965 Pilot pens contain feeds that have decomposed into crumbly junk and a third lacks a feed entirely (gee, I wonder why?).

All three are "dart" nibbed pens: the "dart" (my name) is a streamlined, mostly enclosed nib design, where all that is seen of the nib is a "V" shaped gold point, that crowns at the nib slit and has flat tine faces. Additionally, both remaining damaged feeds are opaque black material, rather than the (seemingly) more common translucent plastics Pilot used in other pens from that era which I have disassembled.

https://live.staticflickr.com/65535/...7b5d1ef3_b.jpgdart nibs by David Wimmer, on Flickr


These come in three sizes as far as I can tell: the smallest, as seen in the larger early 1960s L-100 and smaller late 1960s L-100V. The medium sized nib is featured in the early 1960s Super 150V and the large nib is in the early 1960s U200, with a similar steel nib found in the 3A student pen (no dating on my Korean made 3A).

This is a real shame, since the large and medium iterations of this nib design are inherrently designed to allow easy flex and produce very nice line variation with the right technique...

I wonder if this feed plastic(?) was a material pilot experimented with to improve performance over their earliest generation of plastic feeds, that was abandoned quickly, or if these fell afoul of sumi, scented, or fast drying ink formulas that can cause damage to any pen? I'm leaning toward the former, since later small darts don't have feed decay issues and the large feed in my u200 is standard Pilot frosted/clear plastic and nearly identical to the feed in the 3A (which I suspect is at least a decade newer).

Any experience with this phenomenon, or suggestions about a feed that might be interchangeble in the Super 150V would be greatly appreciated!

UPDATE:

Super 150V #3 has an intact feed with no sign of degradation whatsoever... go figure? It *is* opaque black plastic, rather than the more often seen (by me) translucent dark gray and the casting looks more like the late 50s "mini nib" super 80 or 100 pens, with softer edges on the fins and an overall less crisp precision to the molded part.

I'm hoping to pick up a parts donor L-100V to see if the feed from one of those will fit the other pen that has FDS (Feed dissolution Syndrome).

:D now I'm really glad I wound up with several of the Super 150Vs, it's a cool little pen and being able to at least get one working feels great!

My respons is very general, but still; common plastics at the time were polyester, ABS, or acrylic, among others. I think both high and low density polyethylene might be a possibility. Plastics are never just plastics, a lot of substances where used to make it softer and more flexible. Decades later it's difficult to know what they used in their production. Some plastics have tured out to be very long lasting and stable, but the various additives have made some plastics very brittle, crumbling or even soggy, almost melting as it disintegrates. I can't say for sure, but I don't think the hardest resin based plastics were used for feeds? Bakelite, melamin? Melamin is still one of the best for various purposes.

Is it possible to make replacement feeds in a easy to find current plastic type? Most of if not all of them are still common. I think 3D printers use ABS plastic, lathe machines can use any plastic. Anything can be done if we really want it. Some go for hard rubber when they make feeds for new or restoration pens. I'm just thinking out loud really. If you find a pen with a good nib, it's worth a bit of effort.

Quote:

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Originally Posted by arrow

My respons is very general, but still; common plastics at the time were polyester, ABS, or acrylic, among others. I think both high and low density polyethylene might be a possibility. Plastics are never just plastics, a lot of substances where used to make it softer and more flexible. Decades later it's difficult to know what they used in their production. Some plastics have tured out to be very long lasting and stable, but the various additives have made some plastics very brittle, crumbling or even soggy, almost melting as it disintegrates. I can't say for sure, but I don't think the hardest resin based plastics were used for feeds? Bakelite, melamin? Melamin is still one of the best for various purposes.

Is it possible to make replacement feeds in a easy to find current plastic type? Most of if not all of them are still common. I think 3D printers use ABS plastic, lathe machines can use any plastic. Anything can be done if we really want it. Some go for hard rubber when they make feeds for new or restoration pens. I'm just thinking out loud really. If you find a pen with a good nib, it's worth a bit of effort.

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Hi arrow, the feeds in almost every Pilot pen that was produced from the late 1950s on are complex, close tolerance units that combine the functions of nib retention, internal ink overflow control and interface with the cartridge fitting or other filler mechanism in one unit... I'm certain that it's *possible* to reproduce one, but it's definitely well beyond the scope of a hobyist level 3D printer. I also assume that the specific plastic used, as well as etching or other surface treatments are essential to proper function, Pilot used to use composite ebonite/plastic, plastic+sponge and two-part plastic feeds, but eventually got the results they desired from one piece plastic units, so it stands to reason that this finely tuned a system is fairly detail dependent and wouldn't give great results if features were omitted or poorly replicated. If anything, I'd guess that precision milled ebonite might be the best chance for duplicating this particular feed, the ebonite would have the benefit of being fairly easy to custom fit using abrasives and fine toothed files.

Many of the Japanese made feeds look like acrylic or polycarbonate, but I've never gone after one with solvents to try and determine which...