Polymer and Metal Chemical Resistance

[PJohnP]

I'm probably opening myself up to a storm of vituperative PMs and posts, but perhaps it would help clarify a few of the debates I've been reading on inks, pens, and plastics/polymers with respect to ink effects on pen materials if there were a bit of science and engineering added to the discourse. For that matter, I'll add a few comments on metals as well.

 

Just to set the record straight on the basis for discussion, I'm a chemical engineer and chemist with a pretty long work history in the chemical process and refining industries where corrosion, chemical attack, and materials failure are a part of the daily life for those of us working in the field. My comments are based on industrial experience, not wishful thinking.

 

Firstly, pH, which is a logarithmic measurement of acidity/alkalinity, is not the only threat to polymers/plastics or metals. pH, quite obviously, can have an effect on materials, but chemical attack does not start and stop with pH, which can be attack by H+ or OH- ions, depending on specific pH.

 

Other materials and chemical attack can result in, but are not limited to, polymer swelling, cracking, dissolving, loss of overall mechanical integrity, or a combination of these effects. None of those effects are desirable in a fountain pen.

 

For a simple example (see postscript for an important note on examples), let's consider a Visconti pen, which feed is composed according to one source as ABS (Acrylonitrile Butadiene Styrene polymer). ABS is a pretty robust material, used in many applications, including piping where it experiences fairly high pressure and flow conditions. The Wikipedia entry on ABS notes that, "ABS polymers are resistant to aqueous acids, alkalis, concentrated hydrochloric and phosphoric acids, alcohols and animal, vegetable and mineral oils, but they are swollen by glacial acetic acid, carbon tetrachloride and aromatic hydrocarbons and are attacked by concentrated sulfuric and nitric acids. They are soluble in esters, ketones and ethylene dichloride."

 

So, one would conclude that ABS would be a "perfect material", eh ? After all, we don't expect to find glacial acetic acid in fountain pen ink...

 

Well, that turns out not to be the case, as nothing is a "perfect material". If one turns to industrial data on Chemical Resistance of Plastics Materials and then proceeds to the chart specific for ABS and looks at the various grades of ABS sold by one company, one sees that the material's not so resistant to chlorine or bromine ions, nor is it so good with phenol or aniline. Aniline ? Hmmm... Is that ever used in inks ?

 

One needs also to consider how temperature changes the chemical effects, as these alter with increasing temperature.

 

ABS is also subject to oxidative effects which can be minimised - but not eliminated - by the addition of anti-oxidants in the polymerisation process. Oxidative effects will, over time, change the polymer characteristics and alter the resistivity to chemical attack.

 

Does this mean Visconti is being careless in using ABS ? No, I'd expect that they've employed competent materials engineers to address the most appropriate material for the feed on their pens. However, no material will be resistant to all chemicals that could contact it while having the specific mechanical properties (e.g., resistance to impacts, hardness, colour) that may be needed for the application at hand.

 

And that discussion above is just for one material - ABS - and not the many materials that are used to make a fountain pen, vintage or new. Each material - specifically, each individual manufacturer's polymer material - in a fountain pen would need to be considered carefully for chemical resistance. It's important to also understand that long term exposure will make even materials rated as "fair" for chemical resistance perhaps less desirable. After all, we sometimes consider pens that are several decades old, or more, when we discuss inks.

 

Metals are subject to the same issues, but the polymers are more complex cases due to specific polymer characteristics such as polymer chain-length, cross-polymer linkages, anti-oxidants, plasticisers, colourants, etc. Any of these variations can change the resistivity of the polymer to chemical attack or alter mechanical characteristics or both in ways that wouldn't make the polymer suitable for use in a fountain pen.

 

For example, the types of gold alloys used in pens are relatively restricted for the simple reason that gold only alloys with certain metals, and too pure a gold alloy lacks mechanical strength and hardness, both of which are necessary for a pen nib. Stainless steel is excellent in some applications, but it's eaten away in a high salt environment. Some metal alloys are subject to caustic corrosion cracking effects. Fortunately, metallurgical charts are extremely well defined in many of these applications, and, again, competent materials engineers can manage these issues.

 

However, the many different polymers, metals, and inks in the marketplace create a situation where it's extraordinarily difficult to predict that a given pen will be compatible with all possible inks or that an ink will be compatible with all possible pens, at least, not without having pens where the raw materials would cost orders of magnitude more, the pens would possibly be unwieldy in the users' hands, and the line of the pen laid on paper might please nobody.

 

Put bluntly, there will be some inks that are not chemically compatible with some pens. The degree of chemical incompatibility might be small and slow, or vast and rapid. It all depends on the specific materials the pen's made of and the specific inks within the pen.

 

By the very nature of pens of different ages, different environments (e.g., temperature, light exposure), and different usages (e.g., "hard writers" vs. "soft writers"), the results will span a substantial spectrum. Observations, unless centrally recorded and coordinated, will not follow a completely logical pattern, although it would certainly be possible to try and develop an epidemiological model for the observations. This is, by the way, not "only anecdotal" observations anymore than observations of disease and disease vectors are such - there's hard science and mathematical standards that are followed. But, as noted above, this does require a centralised group to record and coordinate observations in order to derive statistically significant findings. Not having performed such an expansive and expensive study doesn't mean that these events are not occurring, just that the causative element hasn't been shown in a statistically significant manner.

 

This is an extremely complicated subject, one that is the lifework of a number of professionals, and not something that's addressed in a quick and easy paragraph or ten. Not a word of the material above addresses in any way if the ink provides results - shading, colour, flow, permanence - that are at all of interest to the marketplace.

 

 

 

John P.

 

 

P.S. I picked one material based on the information from a single source for the discussion above. I don't know if the source is correct or incorrect, but the references for the ABS chemical resistance are probably not the suppliers for Visconti, so please don't try and derive facts suitable for court hearings from this discussion. It's an example, nothing more, and nothing less.

Edited April 10, 2009 by PJohnP

[Phototoxin]

As a fellow scientist I must say that did cross my mind when buying ink but seeing as buying 'ink' as in proper, real ink 'in a bottle' type ink that is, I just have to trust that it wont melt my pen!

[Lloyd]

For a metallurgic oddity, you might want to take a gander at the Danitrio Gojira with a 24kt nib.

[PJohnP]

As a fellow scientist I must say that did cross my mind when buying ink but seeing as buying 'ink' as in proper, real ink 'in a bottle' type ink that is, I just have to trust that it wont melt my pen!

 

One could hope.

 

However, there are enough well reported cases of pen damage to know that our hopes may not be greater than our fears. At least, that could be true in some cases. Sadly, discussions of this type are often drowned in waves of hysterical defense of specific inks or pens where people let their emotional attachment to a given product overwhelm rational discourse. I was taken aback when I searched on this topic here at FPN at the sometime vituperative nature of some discussions.

 

 

John P.

[PJohnP]

For a metallurgic oddity, you might want to take a gander at the Danitrio Gojira with a 24kt nib.

 

Chuckle.

 

I note with interest the comment, "The nib will be on the softer side, but NOT vintage flex. It will be softer than the Namiki Emperor for instance."

 

 

 

John P.

[Phototoxin]

As a fellow scientist I must say that did cross my mind when buying ink but seeing as buying 'ink' as in proper, real ink 'in a bottle' type ink that is, I just have to trust that it wont melt my pen!

 

One could hope.

 

However, there are enough well reported cases of pen damage to know that our hopes may not be greater than our fears. At least, that could be true in some cases. Sadly, discussions of this type are often drowned in waves of hysterical defense of specific inks or pens where people let their emotional attachment to a given product overwhelm rational discourse. I was taken aback when I searched on this topic here at FPN at the sometime vituperative nature of some discussions.

 

 

John P.

 

You get 'fanboi's in every avenue of the internet from computers, anime, pens, football whatever. The trick is to glean the legitimate information and make up your own mind. Though in my introduction thread where I stated what I ordered no one has posted 'OH NOES IT WILL EXPLODE YOUR PEN !!1!one!!eleven!!!1!' so I think I'm safe... nothing esoteric for me at the moment short of some Hubrin smelly ink for the GF's love letters'

[PJohnP]

You get 'fanboi's in every avenue of the internet from computers, anime, pens, football whatever. The trick is to glean the legitimate information and make up your own mind. Though in my introduction thread where I stated what I ordered no one has posted 'OH NOES IT WILL EXPLODE YOUR PEN !!1!one!!eleven!!!1!' so I think I'm safe... nothing esoteric for me at the moment short of some Hubrin smelly ink for the GF's love letters'

 

Long chuckle.

 

Well, yes, there are certainly a lot people who invest an inordinate amount of time in defending their positions, however they've reached those positions.

 

But back on topic, I'm testing Sailor Kiwaguro Nano Carbon Black in a couple of Pelikans, an older M150 with a 2.0 calligraphic italic nib and an M200 with a GP steel fine nib. I've also rotated a couple of other nibs through the M200 over the last couple of weeks to examine how easily they clean after a day or two in the pen with that ink.

 

I've been looking for a reasonably waterproof black or blue-black, and this one looked interesting.

 

It does have a strongish odour when the nib is held close to the nose, but the ink itself has been remarkably well behaved so far, without feathering, bleedthrough, nib creep, or suchlike behaviours, and the ink cleans out of the nibs and pens easily. The flow onto various papers has been smooth and easy, without skips or dryouts (and I live in a very dry climate!).

 

The piston in each of the pens hasn't shown the slightest binding or other change in movement. I need to grab some pH paper to check the pH on the ink, but when I've examined the nib and feed components with a magnifying glass, I've not seen any pitting, flaking, or deterioration of the metals. I've pulled the main use nib on the M200 about every other day to look at this carefully, so I think that I'd be able to see any short-term effects. I should have more results in a couple of months, I'd hope.

 

Why am I mentioning this here in this thread ? Well, the only way for most of us to make determinations on the effects of a given ink on a given pen type is to run controlled experiments with those two. In this case, my experiment wouldn't scale up to the M800 and above in Pelikans because the piston mechanism materials are different, nor would it necessarily apply to vintage Pelikans. However, it's reasonably likely that "modern" Pelikans from the M100 to the M600 style lines would have similar results.

 

 

 

John P.

 

[Lloyd]

FYI. There are several other Noodlers vs. Pelikan threads in the Pelikan forum, too.

[PJohnP]

FYI. There are several other Noodlers vs. Pelikan threads in the Pelikan forum, too.

 

Aye, I've seen and read that thread and others of the same topic. I'm quite purposely staying outside that specific debate and specific ink in my initial post to this thread, aside from repeating the premise that I made there, Put bluntly, there will be some inks that are not chemically compatible with some pens. All that I will note on the debate you've referenced is that if a specific pen manufacturer states that the use of a specific brand of ink voids warranty coverage, it's worth heeding that warning if one wants warranty coverage in the future.

 

And now, back to my experiment with Sailor Nano Carbon ink in two user level Pelikans. :hmm1:

 

 

 

John P.

[Lloyd]

All that I will note on the debate you've referenced is that if a specific pen manufacturer states that the use of a specific brand of ink voids warranty coverage, it's worth heeding that warning if one wants warranty coverage in the future.

 

And now, back to my experiment with Sailor Nano Carbon ink in two user level Pelikans. :hmm1:

 

 

 

John P.

In the opening of the linked thread, it states that:

We recommend that you use only water-soluble fountain pen ink. Do NOT use water-resistant, waterproof or permanent inks in your Pelikan.

This would include your Sailor Nano-Carbon ink.

[ToasterPastry]

To add a comment...

 

I recently received a nib back from the grinder. He stated that there was, in fact, a pit in the nib. My initial question was that it's 18K gold which resists corrosion, how could there be a pit? In fact, it wasn't the gold, it was the iridium tipping. This is a commonly seen event on vintage nibs. You don't write on gold, you write on the nib's iridium (rhodium, osmium) alloy tip.

[PJohnP]

In the opening of the linked thread, it states that:

We recommend that you use only water-soluble fountain pen ink. Do NOT use water-resistant, waterproof or permanent inks in your Pelikan.

This would include your Sailor Nano-Carbon ink.

 

Just so.

 

That's why I'm testing the ink in a couple of user model Pelikans (no insult to other pen makes - but I own Pelikans, so I test with Pelikans). If a problem arises, I haven't put this into one of the better ones that I own and graunched the piston, the feed, the nib, the body...

 

Hence, it's "testing"... :hmm1:

 

Y'know, I've had a few PMs on this subject with various comments - and, no, I don't tell tales "out of school" about those folks or who they are - so I'll point out again, that in my considered professional opinion :

 

Put bluntly, there will be some inks that are not chemically compatible with some pens.

No nastiness at all intended about that comment, and please also note, no specific brands or pens being singled out. There are simply too many pen materials and too many ink compositions in the world. I would cordially invite folks to calmly explain experiences in this area so we can all learn from these experiences. If the experiences are truly upsetting for someone, I'd counsel them not to post them until they've reached a better accommodation with how upset they are, solely to avoid the emotions clouding reporting information.

 

My comments on the Sailor Kiwaguro Nano Carbon Black ink are intended for exactly the purpose of learning about an ink with a type of pen. Should the ink prove less effective with my pens, I'll report that without rancour or anger, albeit perhaps some disappointment. Others can then decide if the experience I've reported is applicable to them, and make their own decisions if they want to use the same combination.

 

YMMV, and dealer prep with applicable taxes will no doubt be higher for your location...

 

 

 

John P.

[ToasterPastry]

...People get passionate enough about this subject to actually PM you privately?

[Johnny Appleseed]

To add a comment...

 

I recently received a nib back from the grinder. He stated that there was, in fact, a pit in the nib. My initial question was that it's 18K gold which resists corrosion, how could there be a pit? In fact, it wasn't the gold, it was the iridium tipping. This is a commonly seen event on vintage nibs. You don't write on gold, you write on the nib's iridium (rhodium, osmium) alloy tip.

 

Pits on the "iridium" tipping (really an alloy, only sometimes the element Iridium) should not be assumed to be caused by corrosion. Pitting on vintage tipping is often the result of flaws in the tipping pellets, particularly earlier nibs, where the tipping was often raw and irregular pellets of Iridium-alloy material.

 

But it does raise the point that when we discuss ink corrosion, we have to look at the tipping material as well as the gold. How do the Ruthenium and Osmium alloys used for tipping react to various ink properties?

 

John

[swduncan]

This kind of thing is part of why I haven't pursued vintage pens. Life's complicated enough just deciding whether I'm fine-nib guy, or a medium italic guy, or a broad-guy-on-cotton-paper-but-extra-fine-everywhere-else guy, or what kind of ink color best represents what I want.

 

Just considering nib sizes and ink colors there are hundreds of possible combinations. Now add pen styles, nib styles, level of flexibility...

 

And after all that I need to worry about long term modes of failure that might result from unpredictable affects based on indeterminate material combinations?

 

By using recently-bought, easily replaced pens, I can forego that worry. If I put noodler's/Private Reserve/Diamine/Crazy Fernando's ScribbleWash in my pen and it melts down right before my eyes, I'll be irritated, then amazed, then glad that I have a new blog post, and happy I have an excuse to buy a new pen.

 

I'm an engineer as well, and I enjoy geeksturbating over some details as much as anyone, but this seems too much like work...

 

That said, has anyone toyed around with the potential electrolytic affects of various inks and the dissimilar metals of two tone nibs?

[ZeissIkon]

But it does raise the point that when we discuss ink corrosion, we have to look at the tipping material as well as the gold. How do the Ruthenium and Osmium alloys used for tipping react to various ink properties?

 

I can't speak specifically to ruthenium or osmium, but in general, platinum group metals (which as I recall includes osmium, iridium, palladium, rhodium and ruthenium) are about as corrosion resistant as gold, if not more so. Platinum itself is inert to chemicals that will dissolve gold (aqua regia, specifically, will dissolve gold, but will attack platinum only at elevated temperature). Welding these metals to the gold tip is complicated by the extremely high melting point of the entire platinum group; I'd expect they're actually soldered with a filler metal that melts at a lower temperature than gold (silver alloys are common in jewelery making), though perhaps someone who does retipping can correct this if I'm confused. This kind of join is often called "welding" in the jewelery trade, and the join formed is usually stronger than the gold being joined.