I would like to use Diamine registrars ink, but I am wary in part because of the corrosive effects of MB's blue-black ink on metal trim of pens I used many years ago, before learning about the nature of FG inks. People in this forum and ink manufacturers advise regularly rinsing out a pen that uses FG ink. But why? Some say that the corrosive potential of the ink is the result of acid, and some say it results from ionic action. Either way, what would rinsing accomplish? It might interrupt the progress of the corrosion up to that moment, but would it not simply restart after the pen is refilled?

I think the reason why one should frequently flush a FG inked pen is to prevent evaporation. Unlike non-FG inks, FG ink can't be rehydrated after it dries to the point of impaction.

I think your analysis and Lloyd's answer are both correct. (I am not a chemist, and have no experience with Diamine Registrar or any other ferro-gallic ink. But what you both said makes sense.)


If for some reason I were feeling a compulsion to use Diamine Registrar's Ink, I believe I would just use a dip pen with it. Why would a person who is NOT a Registrar in the UK actually need to use the product? (Apart from some emotional bias against Noodler's inks)

I would like to use Noodler's inks, but I don't really think they are ready for prime time, and to judge by other posts in this and other forums, I'm not alone in that. On an objective basis--at least in my experience and in my opinion--they precipitate in the bottle and coat the nib and feed, both of which concern me for what they might be doing to the innards of my pen as well as the look it gives the nib. On a subjective basis--again, just my opinion--I don't think their colors are very well-balanced, nor do I care for the fact that there is a different set of Noodler's inks depending on which store one is talking about. It's still a young company, and there are as many negatives as there are pluses to being run by a founder. When they can figure out those issues, I will be first in line to buy cellulose-binding inks in a range of colors. Until then, however, I'm going to stick with brands that seem to do a better job of balancing a broader range of objectives instead of focusing only on a few.

While I can't recall who, one FPN member kept Diamine Registrars ink in a pen for several months without any problems. I think the modern FG inks are a little more forgiving (just a hope, I guess). Also, I don't think FG inks aren't the only highly acidic ink out there.

I can't write out the chemical equations here because I can't find things like chemical symbols and superscripts and subscripts. If you want to see the chemistry, google "paper corrosion".

Simplified explanation:
Iron gallate ink is made from gallic acid, which is a weak acid, one of the tannins. When you mix it with water, it dissolves, or dissociates into hydrogen ions (the acid part) and gallate radicals. The stuff is corrosive, but not very. Mixed into this brew is ferrous sulfate, which dissociates into iron ions and sulfate ions. The mixture has a weak blue color. The color is so weak, it is hard to write with because you can hardly see it. Manufacturers put in dye so the fresh ink looks like real ink. When you write with the mixture, oxygen in the air reacts with the iron and gallate ions to make a black precipitate. What is left in the solution? Sulfate ions and hydrogen ions, AKA sulfuric acid. The sulfuric acid is in the dried ink on the paper and begins to eat the paper (or parchment) away (corrode it). This takes a long time (hundreds of years if the paper is kept very dry) because the reactions need water.

In a fresh bottle of ink, or one that hasn't had its ink exposed to air very long, you have weak acid and some mildly corrosive ions. No big deal, really. Open the bottle, suck some ink into a pen and mix it with air, and the ink begins to shed black stuff and make sulphuric acid. Eventually, the black stuff could plug the pen and the acid could corrode metal pen parts. So flushing the pen periodically will help forestall the production of the nasty stuff.

What do you do if you want to use iron-gall ink? Put it in a cheap Sheaffer or Pelikan school pen and don't worry about it.

Paddler

Well, I have kept Diamine Registrar's ink in an Esterbrook pen for several months with no ill effects. I don't know what the 2556 nib is made of, (all i know is that it's not gold, silver, or palladium) but it appears to be just fine. I started this as an experiment, but I have found that I like the color of the ink after it "matures". So, I have been using this pen & ink more and more.


As far as cleaning out the pen, this is because the ink oxidizes and forms solids. (This is not the same as "drying out".) Any solids in a fountain pen are bad. So, clean it out. Since these solids are essentially insoluble (unlike many other solids from dried ink) you really want to avoid letting them get to the point of clogging up the works. This is because the water or fresh ink will not dissolve the solids from the FG ink. It's not dried ink, it's just insoluble in water or most inks you would want in your pen. So, flush, flush, flush those solids.

I would still be cautios if using the FG inks in pens with non-precious metal feeds and nibs. Many steel alloys (including some stainless steels) are quite susceptible to corrosion by iron containing solutions. So be careful.

Thank you. Excellent explanation, and likely to be quoted and linked many times.

The ferric gallate is insoluble in water, but will disappear in the presence of bleach -- so the writing is not a permanent as the Noodler's bulletproof inks (although they have not been aged a couple hundred years yet, something else might fade them).

The main problem with ferro-gallate inks is the precipitation problem. In contact with air, the ferrous ions oxidize into ferric ions, and with the gallate form an insoluble amorphous material. This stuff will sludge up the pen badly -- I think I've gotten a couple with this exact problem. Nasty, and you really cannot use bleach on them either, because it is very likely to damage the other parts.

Gold nibs will not be affected, but some (if not all) stainless steel ones can be eventually corroded, both by the sulfate and iron, ions, and worse, the residual sulfuric acid present in the ferrous sulfate to begin with. I believe the chemical reaction also requires low pH, so the ink will be somewhere between 2 and 3 pH anyway, well into the corrosive range.

If I were going to use a ferrogallate ink, I would flush the pen weekly and/or any time I was going to store it unused for more than a day or two. Gold nib only, hard rubber and rubber ink sac only (no Snorkels or pens with stainless steel in contact with the ink). Hard rubber will not be harmed, the rubber sac is easily replaced, and the gold nib will not corrode.

Peter

If you are curious about pH (alkalinity or acidity) of inks in general,
you might want to check out a copy of the Greg Clark Ink Sampler
book. It lists the pH of some of the inks.

Unfortunately, it is out of print.

Outstandingly clear and useful post!

Am I right in thinking that IG ink becomes more problematic the longer a bottle is kept open?

Is there a registrar in the house?

In the UK they do actually use Registrar's Ink (Stephen's commonly) in fountain pens for people to sign the register of births, deaths and marriages. On recent visits, I have been given a Parker to use and to the best of my recollection they were both stainless steel trim and did not have gold nibs; they were "traditional" in design, ie curved not squarish, but I do not know my modern Parkers.

My point is I cannot believe registrars flush their pens very often but simply fill them up and use them, and hand them over many times a day to complete strangers to write in the register. Perhaps registrars get a "pen allowance" rather like some people get clothes allowances.

Chris

That is my understanding. I did a lot of reading on the subject with the intent of making my own FG ink. The gallic acid is "weak", in that it gives up its hydrogen ions reluctantly. The ferrous sulfate dissociates into irons (Fe++) and sulfate radicals (SO4--). All those ions mixed in water make a pretty good electrolyte which will facilitate corrosion (just like in a flashlight battery). None of these reactions are going to be really vigorous until you let oxygen into the bottle (or pen). Then the gallate and iron and oxygen precipitate as the black stuff in the ink and leave behind sulphuric acid, which wasn't there before (much). Sulphuric acid is a "Strong" acid and dissociates in water extremely well and practically throws hydrogen ions at anything it contacts. Remember, though, this is a simplified explanation; there is a hell of a lot of crazy stuff going on in that bottle of ink and what I have written here just hits the high points.

As an asside, you can make FG ink with ferric sulfate instead of using ferrous sulfate. Ferric sulphate has its iron with a valence of 3, rather than two. So to balance the equation, you need two iron atoms and three sulfate groups to make it. Not a good deal: you get two black, inky particles and three molecules of acid that way, instead of one to one.

Paddler

Whilst not a registrar in the births, deaths and marriages sense, my sister was an electoral roll officer at one time and she had to use FG ink for certain documents they had to produce and get people to sign these documents in FG ink too. As this happened around the time of an election, she tells me that they just got a couple of cheap Parker pens from WHSmith and used them with FG ink for the period of that election and then threw them away after, as nobody ever bothered to clean them out and reuse them.

Don't know what light that throws on this discussion if any? I also asked what brand of ink they used, the reply was "they do different brands ?" , so that was not a great deal of help.

The ink would have been made to an "HMSO specification" but provided by more than one supplier as was common with ther public sector tendering of those days.

I found a place in Haverhill which also sells the "HMSO specification" registrars ink, plus a bog-standard cheap Parker (I think it is a Vector with the convertor) to go with it.

http://www.registrarsink.co.uk/

A recent document from a Norfolk Council advises its use in Parish documents...

http://archives.norfolk.gov.uk/documents/p...reservation.pdf

and also in the diocese(sp?) of Peterborough..

http://www.peterboroughdiocesanregistry.co...cordsjuly06.doc

I'm not a chemist, but isn't "the result of acid" "and "results from ionic action" the same thing?