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07-6-2020 14:14:32  #1


Platen with white powder?

Every now and then I see typewriters where it looks if there is a white powder (like talcum powder) on the platen. Now I wonder how does the powder get there?

Was it common in the 60s and 70s to treat the platen with some powder? Or is it some kind of ageing of certain types of rubber?


 

 

07-6-2020 18:35:43  #2


Re: Platen with white powder?

I can't say I've seen anything like that on hundreds of typewriters I've handled and thousands I've seen pictures of. Can you show some pics? It certainly was not a practice to treat platens with a powder at any period. I have often seen what looks like a powder on certain plastic keytops, notably Royals, but that isn't really a powder but a chemical consequence of aging, but platens are a completely different material. I suppose a very dense sprinkling of Wite-Out or correction flakes could look like powder.... Puzzled.

 

07-6-2020 22:44:38  #3


Re: Platen with white powder?

The white powdery residue that you are seeing on 60's and 70's platens is most likely rubber bloom. Often the 60's and 70's machines on which I find bloom have really decent platens with respect to still feeling soft. More info on rubber bloom can be found here:
https://www.boydcorp.com/resources/resource-center/blog/287-understanding-rubber-bloom.html

 

07-6-2020 22:47:34  #4


Re: Platen with white powder?

I've seen this in very old rubber products. I think it is from some type of degradation. I used to work in a bicycle shop that catered to owners of vintage bicycles. I mean VINTAGE. We had lots of stuff from back when the bicycle was called the "safety bicycle" after the decline in popularity of the high wheeler. Some very old tires (or tyres) often have a white powdery or even flaky stuff on them. It's not talcum powder, which is used inside tires to help keep the tubes from sticking and tearing the stems off. It's something else that I've only seen on vulcanized rubber. I've also seen a similar degradation on latex bike stuff, like tubes but that type of rubber usually dries and cracks long before it turns to powder.

Phil Forrest

 

08-6-2020 03:09:28  #5


Re: Platen with white powder?

Thank you for your answers.

Unfortunately I have no pictures from such a platen. Last time I saw it on a Triumph Adler Tippa 1. And I wondered whether it is a good or a bad sign regarding the condition of the platen.

(So next time I may risk to buy a typewriter with a white powdered platen.)

     Thread Starter
 

08-6-2020 03:52:24  #6


Re: Platen with white powder?

AndrewP wrote:

Every now and then I see typewriters where it looks if there is a white powder (like talcum powder) on the platen. Now I wonder how does the powder get there?

Was it common in the 60s and 70s to treat the platen with some powder? Or is it some kind of ageing of certain types of rubber?


 

It could be the owner of said typewriter was using excessive amounts of Columbian marching powder whilst on marathon typing sessions and some of it spilled on the platen https://cdn.boardhost.com/emoticons3/blink.png
.

Seriously though, it is more likely to be the 'bloom' of oxidation, of the rubber, which occurs with the prolonged exposure, over time, to the UV light component of sunlight and the atmosphere in general. 
 

 

08-6-2020 07:46:47  #7


Re: Platen with white powder?

SoucekFan wrote:

The white powdery residue that you are seeing on 60's and 70's platens is most likely rubber bloom. Often the 60's and 70's machines on which I find bloom have really decent platens with respect to still feeling soft. More info on rubber bloom can be found here:
https://www.boydcorp.com/resources/resource-center/blog/287-understanding-rubber-bloom.html

Perfect. Thank you, SoucekFan. I have seen this on other things and "exudate" is the word I wish I could use to explain that plastic keytop phenomenon. I guess the platens I've seen have either not had it or have had it worn off through use. I guess.

 

08-6-2020 09:18:24  #8


Re: Platen with white powder?

I was wondering too what it was. Most of my Triumph/Adlers build after 1963 have it, although very little.

 

30-7-2020 16:36:33  #9


Re: Platen with white powder?

It is white-out. Most likely stemming from correction paper, which has a dry film of white-out on a small sheet of paper, which could correct a character by typing over-it with this piece of paper in-between. Similar to how carbon paper or a carbon ribbon works. They can still be bought and I use them even today regularly. They are very convenient, but can make a mess.

https://cdn.shopify.com/s/files/1/1751/5759/products/DSC03150_1024x1024.jpg?v=1488027221


Learned watchmaker and office machine enthusiast from Germany.

 
 

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