Cleaning Corroded Type

[Roy Watkins]

When unused type has been left for years in damp conditions, the metal becomes corroded with a frosty-looking coating. Does anyone know how to clean type with this problem? I've tried boiling in a baking-powder solution & soaking for long periods in white spirit. Can one do anything else?

[Dan Williams]

What an excellent question. Its one that seems to arise from time to time.
One proper step is prevention, and in this case it seems prudent to store type in some form of controlled environment (AC & heat) when possible.
I know that when the type is cast, there is a sheen of oil on it. I expect that the oil might serve as an unintended preservative, but of course after several years (or typically decades) there isnt anything left of the oil.
My thought on this is that the real obstacle (apart from determining a proper solution, anti-corrosion agent, etc) is the time and effort of manipulation.
Another idea is to prevent or arrest corrosion through use. In other words, the manipulation, handling, inking and then washing of type certainly will slow corrosion. Wouldn't you think?
Then the question is what to do with type, what to put on it, as it is distributed back into the case. My wild guess is to give it the same type of oil sheen that it had to begin with.
Be careful if there is dust, obviously dont go blowing it around or vacuuming it.
Just throwing some ideas out there.

[mike jacobs]

The grey coating on type is a complicated molecule which essentially is a combination of the carbonate, oxide and hydroxide of lead. The other constituants of the alloy, antimony and tin also play their part and add to  the complication of the 'rust' constitution. The first thing to investigate is whether the corrosion has spread to the type faceand if so whether the type is still useable. If it is then any acid will clean the type but my preference is acetic acid. This can be bought from your local Pharmacist as Glacial acetic acid. Dilute it down to about a quarter strength. The licquor left after the type has been cleaned is 'Sugar of Lead' and tastes quite sweet. But resist the temptation to try as it is poisonous.
 
Once thetype has been soaked for a couple of days, wash it in plenty of clean water and rub each piece of type on a piece of greyboard.

The best prevention is the oil used in ink. Type that is used regularly seldom gets attacked by type lice or type rust.

As a temporary measure mix some three in one oil with paraffin and soak the type in this.

As I said earlier, the best preventtion is to use the type and use it regularly.

Good Luck

Mike

[Roy Watkins]

Many thanks to those who replied to my question. I'm very happy to know more of the scientific aspects, thanks to Mike. I've got some glacial acetic acid on order. I'm quite sure that the rot has not gone too far.

Thanks again,
Roy

[Dave Hughes]

I'm tempted to move this to the Solved Problems section unless anyone has anything to add . . .

[Jeff Zilles [jeffo]]

Bit late with this but I was waiting to see if someone would come up with a near labour free method without spending much money that I didn't know about.

Mike's dissertation was excellent and comprehensive but still involves the labour intensive task of buffing off the type, piece by piece, on all four sides and a light scrape top and bottom if you are to do it thoroughly.

With this established I will add my thee pen'orth.

Firstly for ascetic acid read vinegar - cheap and effective - also useful as a photographic stop bath.

If the oxidation is not too severe then for myself I would dispense with the soak and simply buff the pieces on the dark [rougher] side of a bit of recycled carton board - dry cat food, soap powder style cartons - which has been moistened with kerosene [read parrafin in UK].  This fluid is slower to evaporate than more aggressive solvents so the buffing board stays damp longer and it will also provide a smallish measure of non-sticky lubricant to retard recurrence of the problem.

This same system works well in my shop for the occasional drudge of cleaning the sides of Lino mats.

If the face of the type is corroded to the point of pitting then no amount of doctoring will produce a usable result, except perhaps for that worn-out looking 'special effect' !!

jeffo