Oxidation Of Tipping Material

[AidenMark]

I know tipping is very hard material but does nib tipping material oxidise if not used for writing for some time?

Could this partly explain the "writing in" period in new and disused pens - the tarnished layer is being removed by friction?

[Astronymus]

Not every nib labeled "iridium" is really iridium tipped. Often they use other metals instead. Also there might be alloys in use.

[AidenMark]

Not every nib labeled "iridium" is really iridium tipped. Often they use other metals instead. Also there might be alloys in use.

 

 

Indeed - tungsten and nickel alloys are often used I believe. Do these alloys oxidise after a time?

 

When we polish a nib are we really removing an oxide layer rather than the much harder underlying material? I find it hard to imagine alu oxide sanding paper would have much impact on tungsten.

[Astronymus]

I'd say depending on the quality even those metals and alloys will tarnish over time. And as the oxide usualy doesn't share the same characteristics as the source material it would be totally possible to remove such an oxide layer with sanding paper or even by wear on paper. Hypothetical speaking of course. I'm not an expert on metallurgy.

[Andrew_L]

Once I served the vintage pen Onoto DeLaRue of the beginning of the last century. The tip was not polishable to smooth writing. Under the microscope, it became apparent that he had turned into a sponge. I don’t know this is have because of use the active liquid ink environment or poor quality additives to the iridium alloy, but the fact remains. And it is was a 100 year old instrument.

[AidenMark]

Once I served the vintage pen Onoto DeLaRue of the beginning of the last century. The tip was not polishable to smooth writing. Under the microscope, it became apparent that he had turned into a sponge. I don’t know this is have because of use the active liquid ink environment or poor quality additives to the iridium alloy, but the fact remains. And it is was a 100 year old instrument.

 

 

Could IG ink have played a role?

[Andrew_L]

May be. I'm not chemistry specialist, but I saw only one like this nib.

 

... and when I looking the history of Sheaffer for review one of the fountain pen, I found information about Sheaffer issued in 1922. This was a new ink called them is "truly safe." Prior to this, ink was created from very aggressive elements. They were based on less aggressive aniline dyes - it's have a glass jar with a well known now additional pocket for filling.

 

ps: And I think that vintage iron-gall ink from the beginning of the last century and modern iron-gall ink are two big differences.

Edited March 30, 2020 by Andrew_L

[awa54]

I also have an older pen (1920s?) with slightly pitted tipping, it writes very well, but sings slightly on certain papers. I believe that all of the platinum family metals are at least very resistant to oxidation, but alloying elements outside that metal group or porosity in the original ingot might cause these issues.

 

Having looked at un-cleaned vintage nibs quite a bit, I'll say that I haven't seen oxidation on any *quality* nib's tipping, even when the gold or steel body shows some.

[Honeybadgers]

Short answer?

 

No.

 

Long answer?

 

Take a high level inorganic chemistry class.

 

Os and Ir (which make up most of the tipping alloys) don't oxidize at temperatures you'd ever see. Think thousands of degrees celsius before oxygen can start to have fun.

 

A vintage cheap pen with a rolled tip or extremely inferior tipping material could pit and corrode.

 

Porosity of the base metal wouldn't matter. The welding temperature to fuse the ball to the nib would clean that up. It's -possible- that a defect could form during the welding, but that defect would be permanent and come from the construction, not from time.

 

Iron gall inks could never hope to touch modern tipping materials. They'd eat a stainless nib (provided you left it in fresh iron gall ink with stirring for months or years) and leave the tipping behind untouched.

 

Some alloys may slightly tarnish (even gold can) but any such tarnish would come off the first time the nib touched paper.

Edited April 1, 2020 by Honeybadgers

[Estycollector]

"It is the most corrosion-resistant metal, even at temperatures as high as 2000 °C."

https://en.wikipedia.org/wiki/Iridium

[Andrew_L]

I do not want to defend the opposite point of view, but we are not talking about the oxidation of Osmium or Iridium, but about other metals included in the alloy tips. The success of the company Osmia (Faber-Castell) in the 30s of the last century consisted in the use of better quality materials based on expensive osmium, while all other brands used iridium with a large amount of impurities.

[ralfstc]

Hi,

 

I strongly agree with the initial observation (in fact I've asked about it before on here) and would be interested the hear some alternative theories for the "roughness" of nibs that have sat unused for some time (such as 1950s Sheaffers and Parkers).

 

Ralf

[Andrew_L]

I can’t talk about Sheaffer, I was holding only 2-3 instuments in my hands, but about Parker (from Lucky Curve to Sonnet), the all tips are very dense and easily polished to a very very smooth state.

[BaronWulfraed]

I do not want to defend the opposite point of view, but we are not talking about the oxidation of Osmium or Iridium, but about other metals included in the alloy tips. The success of the company Osmia (Faber-Castell) in the 30s of the last century consisted in the use of better quality materials based on expensive osmium, while all other brands used iridium with a large amount of impurities.

Ah, but were they using iridium produced from a smelting operation, or just small pellets as found in nature. I wouldn't consider the latter to be "alloys" -- to me, "alloy" implies all component metals had been heated to melting point, and thoroughly blended, followed by solidification at a rate sufficient to prevent separation.

[Andrew_L]

Ah, but were they using iridium produced from a smelting operation, or just small pellets as found in nature.

 

Yeah! This explains a lot. I think that at the beginning of the last century used the found (mined) granules and this could be part of the problem.

[OMASsimo]

Modern tipping materials, mostly composed of platinum group metals, are basically completely resistant against oxidation under ambient conditions, just as Honeybadgers stated. For some early pens, naturally found alloys like osmiridium were used that could be porous and cause the effects that Andrew_L described. But that wasn't due to oxidation at all but intrinsic to the material. Modern tipping is arc or laser welded to the nib so that it won't be porous. In the early days the tipping material was soldered to the nib and because it was not melted itself preserved it's original structure.

[AidenMark]

There is something I'm not understanding then - if tipping doesn't corrode or oxidise and is very very hard - then what are we doing when we 'polish' the tipping with a sheet of 12,000 wet and dry. The abrasive is Aluminium oxide isn't it?

 

Surely polishing tipping with aluminum oxide paper is like polishing a sheet of glass with a feather duster?

[Newton Pens]

There is something I'm not understanding then - if tipping doesn't corrode or oxidise and is very very hard - then what are we doing when we 'polish' the tipping with a sheet of 12,000 wet and dry. The abrasive is Aluminium oxide isn't it?

 

Surely polishing tipping with aluminum oxide paper is like polishing a sheet of glass with a feather duster?

You're removing sharp edges so it writes smoother. But with 12,000 grit it might take a longer time.

 

Most new nibs have sharp edges (inside of the tines) from manufacturing process and will feel toothy or scratchy. There's lots of info about this online if you search nib tuning and nib grinding and adjusting your nib and all that.

[OMASsimo]

There is something I'm not understanding then - if tipping doesn't corrode or oxidise and is very very hard - then what are we doing when we 'polish' the tipping with a sheet of 12,000 wet and dry. The abrasive is Aluminium oxide isn't it?

 

Surely polishing tipping with aluminum oxide paper is like polishing a sheet of glass with a feather duster?

 

The abrasive in many sanding papers you're referring to is corundum, an extremely hard mineral, just a little softer than diamond. The sum formula of corundum is (almost) Al₂O₃, so technically it is aluminum oxide. Why do you think it wouldn't be able to polish or grind the tipping material?

[AidenMark]

Thanks to the kind contributions of Newton Pens and OMASsimo I spent a fascinating hour with wikipedia learning about the Mohrs hardness scale and Aluminium Oxide a humble mineral with fascinating properties - I didn't know it was used in lipstick. I spy the chance to be extra boring when I tell my wife about this.

 

So corundum (impure Al₂O₃₎ has a Mohrs rating of 9.5 - similar to Tungsten Carbide whereas

Osmium is rated 7 and

Ruthenium and Iridium 6 - 7,

Rhodium and Titanium 6.

 

I couldn't find a rating for the ruthenium, tungsten, rhenium alloys used by high-end pens but I guess they are in the same range as the pure elements.

 

But here is the interesting thing - hardened steel has a rating of 7.5 - 8.

 

So an untipped hardened stainless steel nib would not erode in writing as it is harder than a theoretical pure Iridium tip. However it would be less chemically inert (but perfectly adequate for most modern inks).

 

I have read there are some pure steel nibs for fountainpens without tipping but I had mentally categoried them as cheap, short lived and eventually scratchy (like a dip pen nib). But it seams this need not be the case.

 

Which begs the question, do we still need tipping?